Category: hydroponic agriculture

Higher rates of N application have been associated with discolouration during storage in cabbage and potato. Berard  demonstrated the influence of higher N application rates on the incidence and severity of black midrib in cold storage in the susceptible cultivar Safe keeper. Furthermore, electrolyte leakage in the leaf tissue was reduced at lower N application rate and electrolyte leakage and change in membrane structure increased at higher N application rates . But, according to the previous authors, these results were not consistent during the two years of investigation . However, in the current study, red and green lettuce varieties showed different trends in their browning response related to the chromaticity b* value with respect to the N application rates . The application of higher than recommended N rates in gravel film technique affected the fresh cut visual quality and coincides with the previous findings of Poulsen et al. and Bonasia et al. . In Multigreen 1, the higher N application rates for a shorter time showed lower browning . Therefore, it is evident from this study that the response to preharvest N application rates on browning depends on the variety. Wounding increases the PAL activity . Physiological attributes related to quality attributes and storage life of minimally processed lettuce coincided with increasing concentration of predominantly phenolic acids in different fresh cuts of lettuce cultivars. Increase in specific phenolic acid concentration differed according to the N application in different cultivars in this study . Furthermore, the decrease in phenolic acids and increasing PPO is likely to explain the browning or deep blush brown colour in red Multired 4 during storage with higher N application rates . The reduction in b* value related to the onset of browning in the fresh cuts of Mulitired 4 and Multigreen 3 were minimised by lower preharvest N application rates  due to fairly higher concentrations of ascorbic acid . However, Luna et al.  reported that the ascorbic acid concentrations are higher in red lettuce cultivars compared to the green cultivars.

The higher ascorbic acid concentrations in Multired 4 could probably have controlled the browning and maintained the higher b* value . Multired 4 showed improved shelf life and overall quality due to the higher concentration of phenolic compounds and lower PPO activity than the two green lettuce cultivars . Reducing trend in dicaffeoyltartaric acid concentration was reported during post harvest storage at 5°C and 85% RH . However, a divergence in observation with regards to the increase in dicaffeoyltartaric acid content in Multigreen 1 at similar storage conditions could deny its participation as a substrate for browning mechanism.Hence,hydroponic nft system the import of goods is necessary to meet the food demand of urban citizens, which has caused an increased dependency on the global food production and supply system. Such a reliance on external inputs represents a vulnerability when major political or economic disruptions occur, and it can often be the leading cause of such instabilities. The inequality in food distribution represents an additional risk, worsen by the increasing urban poverty. Adding on to the local challenges for food provisioning, the global food supply chain is also vulnerable to big-scale changes. In fact, climate change will put food security at risk on several levels, for example by reducing yields and land suitability, and by increasing frequency and severity of extreme weather events. Satisfying the demand of fertilizers is another environmental challenge of food production, given that mineral fertilizers are a non-renewable resource that is being consumed at an increasing rate. In addition to being vulnerable to disruptions, the food system is also responsible of environmental degradation; considering the environmental impacts generated by the final consumptions of the European Union, the production and distribution of foodstuff accounts for 30% of the impacts on climate change, 33% of the impacts on ecotoxicity and 60% of the impacts on eutrophication. Urban agriculture has been proposed as a practice to respond to the challenges presented above, and produce positive environmental, economic and social effects, such as shortening the food supply chain, reducing the emissions of greenhouse gasses, microclimate improvement, improved water management, improved diet-related health, and stress reduction. Smit and Nasr pointed out that urban agriculture could promote the development of a circular economy by closing ecological loops using wastewater and organic solid waste as inputs. However, urban agriculture is not a homogeneous practice, and includes, among the others, small commercial farms, community-supported agriculture, community gardens, rooftop gardens or greenhouses, hydroponic and aquaponics farms and indoor agriculture. Mougeot proposed to categorize UA based on types of economic activity, products, location, area used, production system, production scale, and product destination. Given this variability, a case-by-case evaluation is needed to show if and in what conditions UA can deliver positive impacts and can replace conventional agriculture.

Urban agriculture has been studied from a life cycle perspective, reporting different results that show that UA is not a less impacting production system per se. For example, Kulak et al. calculated that up to 34 t CO2eq ha-1 a-1 could be avoided by substituting conventional agricultural products with vegetables from community gardens in the UK. On the other hand, for Goldstein et al. urban agriculture in northern climates performs worse than its conventional counterpart, mainly because of its high energy requirement and/or low yields. Sanyé-Mengual et al. evaluated a rooftop greenhouse production in Barcelona: their results show that the UA system had a lower impact on the environment, but that crop efficiency was determinant for the performance of the cultivation. This case study analyses, from an environmental perspective, a vertical hydroponic urban farm called “La Petite Ferme du Grand Lyon” and based in Lyon , using Life Cycle Assessment. The pilot farm is run by the private company ReFarmers and produces leafy greens and herbs that are sold directly to restaurants and citizens.This work’s goal is to evaluate the environmental performance of a high-yield vertical hydroponic farm, and to compare it to conventional agriculture. The analysis shows whether and to what extent this type of hydroponic is able to produce vegetables with a lower environmental impact than soil-based conventional agriculture. By showing if urban agriculture can compete with conventional vegetable production, this study highlights the strong and weak points of urban hydroponic production in temperate continental climates, and therefore supports the improvement and development of sustainable urban food supply systems. Urban agriculture is, in this case, a supplementary source of vegetables; therefore, the capacity of urban hydroponic agriculture to fulfil the entire food requirement of European cities is outside of the scope of this study. The modelling framework applied is attributional LCA. According to the ILCD Handbook we identified our case study as a Situation A “micro-level, product or process-related decision support study”. In fact, by having a small market share, the farm’s products can impact on the market solely to a limited extent, generating only small-scale consequences [22].We performed a cradle-to-gate analysis considering the cultivation phase and the transport of the products to the retailers. Figure 1 shows the boundaries of the system.The end-of-life of the capital goods was selected depending on the material: steel, aluminium and iron parts are recycled, as well as PVC and PE plastic components; the other plastic materials, which cannot be recycled due to their composition, are sent to incineration. We had to exclude the process of pest control through insect release; the insects are not bred in the farm, and no literature data could be found about the breeding process of parasitoids and the related inputs. The fixation of CO2 by the plants was omitted because the gas is expected to be released in the near future as a biogenic emission of carbon dioxide. Moreover, as we compare the same amount of produced lettuce, the uptake of carbon dioxide is the same for both types of cultivation. Since the fertilizers are not lost through the soil, but remain available to the plants thanks to the recirculation of the water, we assumed the fertilizers emissions to be zero.

For conventional agriculture, we considered two scenarios: the production and delivery of lettuce grown in heated greenhouses  and the production and delivery of open field cultivated lettuce ; both the scenarios were derived from the Ecoinvent database. In all the three scenarios, the packaging of the vegetables has not been included. This choice is justified by the fact that the impact of packaging has been showed to be relatively low [24].The Life Cycle Inventory  of scenario S1  consists of data provided by the farmers, covering four months of production in 2016. The annual production was extrapolated considering the seasonal variation of some inputs, such as the water demand. Moreover, we took into account that the production stopped for 1.5 months in winter due to low temperatures. The losses of production in the farm are indirectly accounted for, since the farmers reported the yields as production ready to be sold, i.e. the losses has been already subtracted. The farm covers an area of around 325 m2 , of which  only 18% were used for the plant cultivation. The seedlings are not produced in the farm but bought from a local organic company; since no direct data were available, we refer to the seedling production process from Stössel et al.. We assumed no heating is required, since the plant variety are selected according to the season. A neighbour farm manages the transport to the retailers of the vegetables from the hydroponic farm, together with their production; a mass allocation was performed to distribute the impacts of this process, and a car trip of 20 km per week was estimated. No losses of products are assumed in this phase, due to the length and frequency of the trip.As an overview, the urban vertical hydroponic production  shows the best performance in the categories of marine eutrophication and agricultural land occupation. For climate change, freshwater eutrophication, freshwater ecotoxicity and fossil depletion, the impact is higher than on-field conventional agriculture . Anyway, in all cases except for water depletion the performance of S1 is visibly better than the production of lettuce in heated greenhouses . These results are explained by taking into consideration the characteristics of the different systems. The vertical hydroponic farm requires more capital goods than the other types of cultivations, since it does not rely on soil substrate, but needs vertical plastic structures and a recirculating irrigation system, which requires electricity . For climate change, nft channel the consumption of electricity contributes for two thirds to the impact in scenario S1, while in scenario S3 the production and use of fertilizers are the main responsible of greenhouse gas  emissions. Whereas these two scenarios differ for only 0.10 kg CO2eq, when lettuce is grown in heated greenhouses , it is responsible of the emission of 7.08 kg CO2eq per every kg of lettuce that reaches the supermarket.

By recirculating water and avoiding losses for infiltration, scenario S1 has a water consumption seven times lower than greenhouse conventional production, and around four times lower than on-field cultivation, that benefits from rain events . In Mediterranean climates, such as Greece, the water demand per kg of lettuce production reaches 83 litres, fourteen times higher than in vertical hydroponics. However, the irrigation system requires a constant water flow guaranteed by a pumping system, which consumes electricity. The impact of electricity depends on how this electricity is produced; given the location of the farm, we considered the French energy mix, of which more than 70% is nuclear energy. The production of nuclear energy has a high requirement of cooling-water, which explains why scenario S1 has a worse impact on water depletion, even if it has a smaller direct water consumption. Table 3. Results of the Life Cycle Impact Assessment of 1 kg of lettuce grown in the three scenarios: vertical hydroponic production , heated greenhouse production and on-field cultivation . The results are normalised with respect to the yields in Table 2. The consumption of electricity for irrigation is among the main contributing processes for all the impact categories, but is less impacting than the consumption of heat of the conventional greenhouse scenario. In facts, scenario S2 has the worst performance  in every category.

As mentioned in the previous section, the weather data in each station are interpolated to determine the temperature for the entire country. In terms of yield per area, the hydroponic production of tomato is found to be greater than open-field production. Hydro-ponic greenhouse tomato production is estimated with a yield of 195.3 kg/m2/y, whilst the yield in an open field is projected at 3.23 kg/m2/harvest. It is assumed that the duration of harvest for tomato is every 2 months during the year and that there are zero harvests during the summer period . Consequently, the estimated yield in an open field is estimated to be 9.69 kg/m2/y. The high yields of hydroponics production of tomato result from the controlled environmental conditions maintained within the hydroponic greenhouse, which allow for continuous production all year round. The advantages of hydroponic production will vary depending on the operational parameters under which the crop is grown and is not unique nor limited to tomato alone. Similarly, water utilization in a hydroponic greenhouse and open field production of tomato in Qatar is compared for various seasons. The results summarized in Table 8 indicate that less water demand is required in hydroponic production in comparison to open field production. Therefore, it is considered as a more efficient farming method, due to the fact that the hydroponic system delivers the water more resourcefully, with a larger percentage of the water going to plant evapotranspiration . The tomato crop evapotranspiration per season for open-field agriculture and hydroponic greenhouse as a growing method is summarized in Table 9. The result demonstrates that hydroponic is more efficient than open field by 5%, where it saves around 4000 mm/day/season in the summer.

Due to the controlled nature of the climate within a greenhouse, the amount of crop water lost by evaporation and transpiration processes would be reduced. All greenhouses have the capability of reducing evapotranspiration through increasing humidity and entrapping moisture level, flood tray physically blocking wind, and reducing the solar radiation by filtering out some direct sunlight that reaches the plants; this is due to the greenhouse’s protective covering that performs all of these three functions. Results for energy consumption per each component in a hydroponic greenhouse for tomato production in Qatar are illustrated in Appendix C. Due to the availability of 40 ha for the production area in Agrico farm, it requires more energy for cooling in comparison to other three farms. Moreover, the energy for supplemental artificial lighting is assumed to be constant for all seasons, as it set to the optimal value required in tomato production. Furthermore, the results demonstrate that most of the energy consumption in the hydroponic greenhouse is due to the cooling loads. This is primarily due to the fact that the greenhouse is located in AlKhor, in the North of Qatar, an area which can have average temperatures of 40 °C in the summer and 20 °C in the winter. However, if greenhouses are to be located in more reasonable climates that are closer to the greenhouse set point temperature, they would experience a lower energy requirement. The other use of energy for the hydroponic greenhouse is for supplemental artificial lighting, which is used to maximize crop yield and maintain consistent production year-round. Some systems use supplemental lighting to create a 24-h photoperiod, especially during the first few days of plant growth, whereas others may use supplemental lighting for only a few hours a day . In addition, small and low-output systems may not use artificial lighting at all. However, in this study, it is assumed that the maximum yield is desired . In addition, the other energy components that affect total energy consumption in the hydroponic greenhouse include the energy used to pump groundwater from approximately 40 m depth for irrigation purposes, and the energy used to distillate brackish water using reverse osmosis technology.

The energy consumed by RO plants is calculated only for SAIC farm due to the onsite availability of two RO plants with a capacity of 370 and 700 m3/day, and by considering a value between 0.5 to 3 kWh/m3 for specific energy consumption . Furthermore, one of the objectives of the study is to observe how changes in technology or production methods can affect the utilization of water and energy in farms. Accordingly, water and energy consumption are also estimated for the four farms assuming an open field for tomato production. The overall energy consumption in both open field and hydroponic greenhouse are summarized in Table 10. The main observation demonstrated from the assessments is that the node is affected by seasonality, growing method and size of the production area. Different seasons will have different water and energy consumption, this is especially noticeable in an open field scenario, where in summer, open field farms will suffer from high temperatures leading to high evapotranspiration and hence higher water demands. Furthermore, as stated previously, depending on the production method  used for tomato, a large variation within water and energy consumption exists. The production area also influences the overall energy and water demands, where Agrico is the largest farm in comparison to the others with an area of 40 ha with corresponding hydroponic energy needs of 5133.3 kJ/kg/year. Although SAIC farm has a smaller area of 2.8 ha, it still consumes large quantities of energy in the hydroponic greenhouse due to the two onsite RO plants.Increasing consumption of natural resources and energies, global environmental problems have appeared. Nowadays, many people face major environmental issues. Especially water problem is spread around the world . Approximately 2.4 billion people are in strict water-stressed condition . The deterioration of water environment has been accompanied by the factors concerning health hazard and agricultural production. On the other hand, two-thirds of fresh water in the world is irrigation water for agriculture to provide foods. Because of these reasons, food production is strongly close to water issues. Hence, preservation of water quality and economy is important ranging from human life to agriculture. According to these various studies, the assurance of high water quality is serious issue to be solved.

In agriculture, advanced technique against environment stress for high quality vegetable production has been discussed by many researchers , and they mentioned that it is more important to control nutrient solution in water circulation systems. The pH in nutrient solution is related to the plant growth and nutrient components in hydroponics. The nutrient solution used in hydroponics has been related to pH, electrical conductivity , ion concentration, temperature  and additional chemical compounds. Hydroponic system for agricultural production has several advantages such as it can use unsuitable area, independence of environmental conditions and easy controlled root systems. Moreover, plant factories adopt hydroponic system because the plant factories need cultivation systems to control plant growth and produce high quality. In this study, we focused on nutrient solution especially water structure. Water is a unique liquid in our world and has a highly structured liquid . Recently, many water analyses were carried out to investigate water structure to know hydrogen bonding and hydration effect. For example electrolytes solution is assessed through viscosity , thermally stimulated current method  and 1 H NMR spectroscopy . One of dynamic status in water expresses viscosity.Therefore, viscosity as one of the fundamental macro parameters in a solution was evaluated for water status such as ion concentration, temperature and pressure . The absorption of water is essential for the growth of most plants because they lose large amount of water daily. Plant cells constitute approximately 90 % of water. Therefore, water state surround root systems of crops is important in agricultural production. However, the relation in water structure including the state of hydrogen bound formed water molecules and physiological function of plant growth has not been clarified. As the viscosities decreased in the nutrient solution for plant growth, recent studies have suggested that the uptake of ions and water by plant roots would be easier . Other research has demonstrated that the thermally stimulated current method, the method of water analysis, has carried out for hydroponic system . For growth of plants, ebb and flow tray the using water to prepare the nutrient solution is limited by water quality . Therefore, quality and structure of water for agricultural use is expected to continue improving.

However, water structures are difficult to apply hydroponic system due to complex relationship between roots and waters. For this purpose in this study, nutrient solutions in various concentrations of ions were compared concerning viscosity. In addition, viscosity of nutrient solution was measured not only in different concentration but in different temperature. The data obtained from this experiment will be to control nutrient solution in hydroponic system for production of high quality vegetable and stable production.Evaluation of water structure influenced by ion concentration is complex phenomenon such as ion-water molecular interaction and states of hydrogen bond in water. In general, viscosity is one of general value which are information regarding ion-solvent interaction and fundamental state deciding dynamics property of water structure making or breaking characteristics. Therefore, the viscosity is one of the fundamental parameters deciding dynamic property in the water. In this experiment, viscosity was focused and measured with a digital rotary viscometer as adapted measurement of low viscosity. LCP  was used for spindle, and revolution speed of the spindle was 100 rpm. The samples of nutrient solutions were taken 18 mL into sample adaptation by a pipette. The viscosities were recorded during 7 min except 3 min after starting an analysis. Averages of viscosities were calculated using last 2 min . Because water temperature influences the viscosity of solution, water temperatures of all samples were measured before measuring viscosities by thermocouple. The water temperatures were controlled by a low-temp thermostatic water bath  circulated surround sample adapter. The average of all plots was recorded and all samples were carried out in triplicate. For comparison of viscosities in different temperature, nutrient solution fixed its concentration and temperature only changed over 5-35 o C.In relation between viscosity and EC value, the viscosity significantly increased with the increase in the EC value . Regression analyses showed that there were significantly positive correlations between viscosities and electrical conductivities . In general, this tendency of increasing viscosity explains that main cause was the different concentration of ions due to structure making effect. This result suggested that nutrient solution changed its viscosity during cultivation period. Without automatic managing ions concentration, nutrient solutions during cultivation period increase or decrease at end of growth period. According to previous study, hydration of inorganic ions can assort into two groups, one is “positive hydration” and the other is “negative hydration”. These groups have different behaviors in water. “Positive hydration” forms ordering water structure by bivalent, trivalent ions and alkali ions. On the other hands, “negative hydration” behaves structure-breaking on the water structure by univalent ions . Concentrations of positive hydration ions, especially magnesium and calcium, dissolved nutrient solution. This result indicated that nutrient solution was observed higher viscosity due to shift concerning ion concentrations. Antibiotics are widely used in medical treatment, veterinary medicine, aquaculture and other areas.

The global annual consumption of antibiotics in agriculture, aquaculture, and livestock husbandry reached 100,000–200,000 tons  and the amount of antibiotics used worldwide is expected to reach 106,000 tons in 2030 . However, 30–90% of antibiotics are excreted in urine and feces as parent compounds or metabolites . Therefore, antibiotics are constantly released into the environment. Existing studies have shown that antibiotics are widely found in water environments , posing a great threat to humans, animals and aquatic habitats . When Iris pseudacorus and Typha were exposed to 2 mg/L of furosemide, the plants have a positive growth rate at the end of 21 days experiment . Concentrations of fluoroquinolone antibiotics , particularly levofloxacin , in the upper ng/L to lower μg/L range are frequently detected in wastewater . LOFL is widely applied as an antidysenteric and antibacterial agent and for the treatment of pneumonia and immunodeficiency virus . Existing research has shown that the environmental fate of FQs is influenced by photodegradation, adsorption, and biodegradation.

The quantity of P present in the control streams is much bigger than the one in the struvite streams, with the former irrigating and leaching 2.07 and 1.41 g of P per plant for the entire crop cycle, respectively. The fact that the P leachates are one order of magnitude smaller when using struvite  could be related to the slow-release characteristic of struvite reported in the literature. A clear benefit of this finding is a decrease in both P depletion and freshwater eutrophication related to the leachates flow. Moreover, if the leachates of struvite treatments do not contain a large amount of P, it means that most of the struvite has been whether taken up by the plant or remains undissolved in the substrate. When comparing Figs. SM12 and SM18 of the Supplementary material, we can see that P release by struvite is highly dependent on the input water flow, represented in Figs. SM11 and SM17 for the validation and determination test, respectively. Because the volume of irrigated water was three times less in the determination test , the P observed in the leachates is less than in the validation test, considering the period where P was not supplied through mineral fertilizer in the validation test. Differences are observed within the struvite treatments in Fig. 4, highly dependent on the quantity of struvite that was applied at the beginning of the crop. Treatments S1 and S2.5 stopped emitting P in the leachates just 14 DAP, which could have triggered P deficiencies. On the other hand, treatments S15 and S20 were the only struvite treatments that did not stop emitting P to the leachates flow.Treatments S1 and S2.5 had lower yields than the control treatments, establishing a clear relationship between the yield and possible P deficiencies in these treatments. However, struvite remains undissolved in all treatments,mobile grow rack even though the production and the distribution of P among plant organs was different between treatments .

The fact that we have undissolved struvite even in treatments S1 and S2.5 shows that the limitation is not only related to the quantity of struvite available, but also its dissolution . While the struvite dissolution has been previously deemed to be due to the crystal granule size and placement previous literature fails to report the effect of the irrigated water flow. Previous experiment on the struvite dissolution in deionized water make clear that a greater dissolution can be ensured with greater temperature and stirring energy as well as an acidic pH reaching greater dissolutions close to the commercial fertilizers. On the other hand the volume of water flows added to the crop has not been regarded as a determining factor when granulated struvite is directly added to the substrate, especially in hydroponic production. The obtained results in the present work shed light on the effect of the incoming irrigation on the struvite dissolution as well as loss of P in the leachate. Because the volume of irrigated water was three times lower in the determination test, the P observed in the leachates is lower than in the validation test, considering the period where P was not supplied through mineral fertilizer. Moreover, there is a significant amount of P accumulated in the substrate bag at the end of the treatment in the control test. This stored P will be depleted if a successive crop is planted, since the small nursery plants will not benefit from all of it due to the lower needs of a smaller plant. With the addition of irrigation the accumulated nutrients in the perlite bag would eventually be moved to the leachates. By applying struvite this P is not stored and thus, not lost. Based on the findings of this study, a well-designed struvite crop cycle needs to take into account two essential parameters. First, the quantity of struvite, considering that the quantity that remains undissolved at the end of the crop can be used again for a successive cycle. Second, the irrigation management, considering that if we modify this variable to increase the dissolution of struvite granules, we would also be increasing the P in the leachates.

Moreover, since previous studies highlighted the effect of the surface area of the granules on the solubility of slow-release fertilizers , the size used in our study seems adequate for the balance between P supply and P lost through the leachates. Literature with higher sizes reported solubility problems that affected early plant development , while studies using lower sizes or powder do not report these problems . Additionally, the use of nursery plants is preferable since the struvite low dissolution has been reported to be a disadvantage when providing P to feed the transition from seeds to nursery plants . Struvite supply per plant should always be above 5 g for Phaseolus vulgaris, considering that more quantity of struvite would release more P into the leachates, but ensure that P is available for plants. On the other hand, we should also account for the nutritional value of the beans, considering the ultimate function is to produce yield. In this sense, P in the biomass was a variable where the control treatment had a better performance than struvite treatments. This uptake of similar P from struvite compared to soluble fertilizers has been previously reported by Ahmed et al. determining that different crops have a greater uptake of P while other have comparable or even lower growth. While Phaseolus vulgaris was not previously observed, a study with soybean was performed compared to the P uptake with triple superphosphate . The resulting crops show a similar uptake of both P sources by the plant with different quantities of P applied . The P uptake in Phaseolus vulgaris with the use of struvite compared to monopotassium phosphate can also be seen in previous literature although this experiment also explores the use of rhizobium inoculation as substitute for the N fertilization, obtaining a general reduction of plant growth. It is also important to keep in mind that the quantity of applied struvite is 2 g and 5 g for the proposed treatments. Rech et al., 2018 also discusses the low solubility of struvite compared to TSP, also mentioning a greater uptake of P by soybean and wheat with struvite fertilization compared to the control treatment. Only S15 and S20 reach a similar P amount to the control in all plant organs. For this reason, a quantity between 15 and 20 g of struvite, a responsible irrigation management and growing successive crops with the same substrate constitutes the best option to grow a well-designed struvite bean crop cycle. Although the P uptake of the struvite fertilized treatments appears to be equal or rather smaller than the control treatment the production is greater for all treatment with more than 5 g of struvite.

In the literary review proposed by Ahmed et al., 2018 the increase of biomass and yield by plants fertilized with struvite can be related to the simultaneous dissolution of Mg and NH4+. Although the uptake of P is reported in this study the Mg and NH4+ concentration in the plant was not analysed. The Mg uptake has been reported to be strongly correlated with the given Mg in the struvite and can be pointed out as a possible source reason for greater growth and production .Worldwide, fresh water scarcity is increasing demand for water reuse in agriculture, and municipal wastewater is a common and widely available irrigation source . Currently, twenty-four countries permit food crop irrigation with treated municipal wastewater, and eight countries permit irrigation with raw, untreated wastewater . Irrigating food crops with municipal wastewater is not without risks to soil chemistry , soil quality , microbial communities , and plant productivity . Wastewater irrigation also increases the availability of anthropogenic organic chemical uptake to plants and subsequent human consumption . In the United States, treated municipal wastewater is used to irrigate agricultural crops for direct and indirect human consumption . Wastewater irrigation of food crops intended for direct human consumption is more stringently regulated, and the U.S. Environmental Protection Agency provides guidelines  although individual states issue permits for food crop irrigation . Current guidelines do not address non-regulated organic chemicals or chemicals pending regulation on the U.S. EPA Contaminant Candidate Lists . Critical knowledge gaps persist regarding exposure risks to humans consuming wastewater-irrigated food crops . Goodwin et al. reported that public acceptance of water reuse improves when public engagement about water reuse addresses crop safety, and developing frameworks for public health risk-based targets is the most frequently prioritized action item in the 2020 USEPA National Water Reuse Plan . Organic chemicals of concern  include regulated legacy pollutants, such as polycyclic aromatic hydrocarbons, pesticides, ebb and flow table industrial solvents, and ammunitions, and non-regulated chemicals including pharmaceuticals and personal care products, engineered nanomaterials, and perfluorinated compounds .

Recent studies have evaluated COC presence and distribution in plant tissues in wastewater irrigated food crops based on physio-chemical characteristics, plant physiology , and targeted quantification of specific COCs . Generally, COC concentrations were greater in plant roots than shoots and fruits . Plants exposed to COCs in hydroponic systems had greater COC concentrations in plant tissues than plant-soil systems due to COC sorption to soils and reduced bio-accessibility . The US EPA uses hydroponic studies to evaluate the uptake and distribution of various COCs such as pesticides, pesticide residues, and emerging contaminants . USEPA OCSPP 850.4800 method exposes target food crops to hydroponic solutions for two weeks to assess COC uptake to plants . Across varied chemical use categories, industrial/surfactants, pesticides, pharmaceuticals, and personal care COCs concentrations were greater in growth solutions than plant leaf or fruit tissues after exposure . Translocation factors were larger for leaf versus fruit tissues and clear trends were not apparent between log Kow and translocation factors. For these reviewed studies , COC concentrations in plant tissues were several orders of magnitude lower than published average daily intake values . Targeted hydroponic studies often address specific COCs within a chemical use category or class and are not holistic assessments of chemical mixtures present . Fu et al. recommends that COCs detected in edible organs or roots of wastewater-irrigated food crops be prioritized for health risk assessments and that non-targeted and suspect screening analyses high resolution mass spectrometry are needed to refine and resolve COC presence and metabolism by plants to provide a more holistic human exposure assessment of chemical mixtures in irrigated food crops. Recent studies have used NTA HRMS to evaluate organic COCs in various water sources including surface waters , ground waters , and municipal waste waters .

Municipal wastewater can contain thousands of chemical features of which only a small portion are tentatively-identified chemicals . Few studies have used NTA and SSA HRMS for COC evaluation in plants or for the evaluation of food crops irrigated with municipal wastewater . This study compared NTA and SSA HRMS analyses of soybean tissues and seed produced in hydroponic solutions of different irrigation sources from an agricultural watershed to assess the diversity and chemical category use of COC uptake from varied irrigation sources. One hydroponic study followed USEPA OCSPP 850.4800 method for 14 days while a second study continued for 56 days to produce fruit and seed. NTA and SSA HRMS results were compared to HRMS results from passive samplers that were incubated for 14 days in the same irrigation sources. We used soybean, Glycine max L., as a model food crop and collected secondary-treated wastewater from a municipal land treatment site , surface waters , and ground water from the LTS and off-site of the LTS in an agricultural watershed. Municipal tap water amended with Ionic Grow™ was used as a reference treatment. We hypothesized that more chemical features and identifiable COCs would be detected in hydroponic soybeans grown in municipal wastewater than other watershed irrigation sources or the reference municipal drinking water. We expected comparable number and abundance of chemical features and tentatively identified COCs in the passive samplers versus extracted irrigation sources and extracted plant tissues.

Whilst the increase in ABA was not replicated in soil-based experiments, we did observe an increase in biological activity  when both earthworms and plants were present. This could indicate a potential synergistic relationship between plants, soil microbes and earthworms, which could be further investigated using the developed methods. Differences between the results of the hydroponic and soilexperiments may in part be due to the use of different earthworm species. E. fetida are litter feeders and L. terrestris are an anecic  species, and consequently they will interact with the soil differently. Differences between the two species in terms of e.g. sensitivity to toxicants  and biochemistry  in addition to behavioural differences are well established in the literature. The additional complexity of a soil matrix compared to hydroponic solutions will inevitably increase associated difficulties in the extraction. It is also possible that increased biological activity in soils compared to hydroponic experiments leads to degradation or conversion of phytohormones during extraction. There is therefore scope to improve the extraction method to achieve better recovery, allowing the observation of more subtle changes in phytohormone concentrations within soils.Perfluoroalkyl acids  have been detected ubiquitously in water , biota and the atmosphere as well as in humanblood serum and breast milk . They have known and suspected toxic effects , and human exposure occurs via food . In response to concerns about these chemicals, the European Food Safety Authority established tolerable daily intakes for perfluorooctanoic acid and perfluorooctane sulfonic acid,and they have recently presented a proposal to add perfluorononanoic acid and perfluorohexane sulfonic acid while reducing the TDI for the sum of all four . To ensure that the TDIs are not exceeded, we must understand the sources of PFAAs in food. Crops are one possible vector for PFAAs into the food supply.This work aims to further our understanding of how PFAAs are transferred from soils into crops. Plant uptake of PFAAs via the roots has been studied using several experimental designs.

The first studies published were soil based experiments. Stahl et al. and Lechner et al. showed that the concentration of PFOA and PFOS in several crops was linearly proportional to the concentration in the soil in which they were grown. Since then there have been several reports of uptake of a broad spectrum of PFAAs in vegetation growing in biosolids-amended soils. They show that the length of the per- fluoroalkyl chain is the dominant variable influencing PFAA uptake in foliage. Foliage concentration factors  are negatively correlated with chain length . For grasses, vertical grow tables an average decrease in FCF of 0.24 log units per CF2 group was observed , while for lettuce and tomato plants the average decrease was 0.3 log units per CF2 group . Regarding PFAA accumulation in root tissue, a much weaker influence of chain length has been observed. For instance, the variation in root concentration factors  for C5eC10 perfluoroalkyl carboxylic acids  was just 0.5 log units for radish, celery, tomato and pea . A similarly small variation was found between PFHxA, PFOA, PFBS, PFHxS and PFOS in wheat  . In contrast, root concentration factors in chicory showed a pronounced dependence on the chain length, suggesting that root accumulation is influenced by species and soil type . Hydroponic experiments provide an opportunity to obtain a more systematic understanding of contaminant accumulation in plants. For instance, a hydroponic experiment was used to assess the influence of different metabolic inhibitors on the uptake of PFOA and PFOS in maize shoots . The influence of pH on PFAA uptake into maize roots was also elucidated in a hydroponic experiment, showing no effect in a pH range of 5e7 for nine of the ten PFAAs studied . A hydroponic study was used to explore the effect of temperature and salinity on PFAA uptake in wheat, identifying a positive effect for both, which was attributed to increased evapotranspiration . Hydroponic experiments have also been used to study how perfluoroalkyl chain length influences uptake in plants. PFAAs with perfluoroalkyl chain lengths ranging from 3 to 13 were all transferred via the roots to the plant foliage in lettuce, tomato, cabbage and zucchini . Transpiration stream concentration factors  for C4eC10 PFAAs ranged over just a factor of two for three of the four species. Relatively high TSCFs of 0.05e0.8 showed that the PFAAs were clearly able to cross the Casparian strip and plasma membranes that prevent the passive entry of many polar molecules into the vascular tissue of the root . A weak influence of chain length on TSCF was also observed in grass . Hydroponic studies have also been used to study PFAA uptake into roots. In lettuce, the root-nutrient solution concentration factor decreased with chain length for C4eC6 PFCAs before increasing by almost 3 orders of magnitude from PFHxA to PFUnA.

While the accumulation of the shorter chained compounds was explained by uptake with the transpiration stream, the uptake of the longer chained compounds was attributed to sorption to the surface tissue of the roots . Hydroponic experiments with tomato, cabbage and zucchini showed a strong positive relationship between root-hydroponic solution concentration factor and chain length for C4eC11 PFAAs, indicating that root-surface sorption was the dominant uptake mechanism for all of the PFAAs in these species . In detailed experiments with a hydroponic model plant system , Müller et al. also concluded that the root uptake of all but the shortest PFAAs was governed by sorption and observed that the dead roothydroponic solution concentration factor increased by almost 3 orders of magnitude from PFBA to PFOS. Comparing the results from hydroponic and soil experiments, there are clear differences in the chain length dependence of PFAA uptake. In foliage, the hydroponic studies show a weak dependence of uptake on chain length, while soil studies show a very strong dependence. The opposite is the case in roots; the hydroponic studies show a strong positive chain length dependence that is attributed to sorption to root surfaces, while the soil studies show a weak dependence. It is unclear what the reasons for these differences are, and how and to what extent findings from hydroponic studies can be transferred to natural soil systems. Sorption of PFAAs to soil solids is certainly an important factor, as this reduces the fraction of chemical available for uptake by the roots. To be able to sorb to the root surface or be taken up with the transpiration stream, the compounds first need to be present in pore water. Long chain compounds sorb strongly to the soil; hence, for a long chain PFAA much higher concentrations in soil are required to generate a given concentration in pore water than for short chain PFAAs . However, there may be other factors that affect the comparability of hydroponic and soil systems. For instance, some contaminants appear to be taken up through the action of root exudates , which would be highly diluted or not present under hydroponic conditions. Another possibility is that differences in the nature of root tissue when grown under hydroponic conditions influence PFAA uptake and translocation. The uptake of the PFAAs could also be influenced by other solutes present in the soil. To explore these questions, we conducted a lysimeter experiment in which lettuce was grown in soil containing PFAAs, and compared this with our previous hydroponic experiment conducted with the same plant species, chemicals, sample preparation and analysis. The lysimeter soil was spiked with 11 PFCAs and 2 perfluoroalkane sulfonates . Four lysimeters were used, each with a different spiking level. At maturity the lettuce was harvested and the roots and leaves were analyzed separately.

Additionally, the PFAA concentrations in soil and pore water were determined. The measurement of concentrations in pore water facilitated comparison of this experiment with our earlier hydroponic greenhouse study, and thereby identification of differences in the uptake into roots and leaves between soil and hydroponic growth environments.The field experiment was conducted at the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Schmallenberg, Germany. Lettuce plants  were grown in 5 lysimeters, one containing soil with background concentrations of PFAAs , and 4 with intended concentrations of individual PFAAs in soil of 0.1 mg/kg, 1 mg/kg, 5 mg/kg and 10 mg/ kg . This compares with PFOA and PFOS concentrations of ~1 mg/kg measured in contaminated agricultural soil in Arnsberg, ~30 km from Schmallenberg . The results from the highest spiking level were not used because the lettuce plants were significantly smaller at the time of harvest than those growing in the lower exposure levels, indicating that PFAAs had phytotoxic effects . Phytotoxic effects of PFAAs have been reported elsewhere . Each lysimeter had a surface area of 1 m2 and a total depth of 60 cm. The lysimeters were each filled with ~450 kg sand  and ~450 kg of loamy sand . This resembled a typical soil from northwestern Germany. The soil used for the upper layer is available as a reference soil  from Fraunhofer IME . The spiking of the soil was done stepwise. First a stock solution was prepared containing all PFAAs in methanol. With this stock solution 2 kg of soil were spiked. Afterwards the 2 kg spiked soil was mixed with approximately 90 kg of soil in a concrete mixer to achieve the desired concentration. This was repeated 5 times for each layer in each lysimeter. Samples were taken from each batch and combined to determine the initial PFAA concentration in the soil of each lysimeter. The lettuce plants were pre-grown in a greenhouse for 2 weeks in non-spiked soil before they were transferred to the lysimeters. Within one week of preparing the spiked soil, 20 lettuce seedlings were put in each lysimeter . The seedlings were watered after planting, and kept humid by rain events until harvest with supplementary watering when needed . After 72 days the lettuce plants were harvested . The plants were divided into roots and foliage, packed in freezer bags and stored at  20  C until analysis. Soil samples were taken with a soil corer when the plants were harvested. The soil core, which was taken from the top to the bottom of the lysimeter,flower pot was divided between the upper and lower soil layers, and the soil was packed in freezer bags and stored at  20  C for later separation of pore water and analysis.Before homogenization with a household blender  the roots were rinsed with demineralized water to wash off residual soil and then carefully dried superficially with paper towels. As no residual soil was visibly apparent on the leaf samples, no cleaning was performed. The extraction method used is based on the modification Vestergren et al.  proposed for the method published by Hansen et al. . Briefly, 10 g of the homogenate were weighed into a 50 mL PP tube and spiked with mass-labeled surrogate standards.

After adding 5 mL of 0.4 M NaOH solution and vortexmixing, the samples were left in the refrigerator  over night to allow the internal standards to distribute in the slurry. Next, 4 mL of 0.5 M tetrabutylammonium hydrogensulfate solution and 5 mL of a carbonate buffer  were added to the samples and thoroughly mixed. After adding 10 mL MTBE and vortex-mixing for 1 min the samples were sonicated for 10 min. Phase separation was achieved by centrifuging for 10 min at 3000 rpm. The MTBE phase was transferred to a new 50 mL PP tube and the extraction repeated two times. The extracts were combined and concentrated to approximately 2 mL using a Rapidvap . After adding 1 g of sodium sulfate to Florisil SPE-cartridges to remove any remaining water in the extracts, the cartridges were conditioned with 10 mL MeOH and 10 mL MTBE before they were loaded with the extract. The elution of the non-polar matrix was done with 10 mL MTBE before the target compounds were washed off the cartridge with 10 mL MeOH/MTBE . This extract was again evaporated to 1 mL final volume. An additional clean-up step following the Powley method with ENVI-Carb  was added when the final extract was still strongly colored.

Plain film radiography is an economical method of visualising radio-opaque objects, but computed tomography still remains the gold standard of initial imaging. However, in cases of organic foreign bodies, magnetic resonance imaging  may be required, as wooden objects tend to mimic air on standard CT window settings. Although complications associated with intra-orbital trauma include visual loss, orbital inflammation, secondary infection, osteomyelitis, ptosis and even brain abscess, in rare cases, no visual morbidity occurs. In this case, although the foreign body was there for more than a week, the patient did not have any associated orbital cellulitis. This may be due to the inert nature of the foreign body, unlike in cases of intraorbital organic foreign bodies. Interestingly, the kind of injury sustained in this patient, i.e. a foreign body embedded in the inferior orbital rim and causing a fracture, is usually associated with high velocity injuries and thus greater visual disability. Our patient was fortunate as his vision was still 6/6 in both eyes, and he did not develop any long term ocular complications. Patients with suspected intraorbital foreign body are usually started on systemic antibiotics because of the high incidence of secondary orbital infections. Anaerobic coverage should be provided where the foreign body is suspected to be composed of organic material. Our patient was started on amoxicillin clavulanate for broad spectrum Gram-positive and Gram-negative coverage, and metronidazole for anaerobic coverage. Management of the intraorbital foreign body depends on clinical presentation, nature and the location of the foreign body in the orbit. Because foreign bodies can cause irritation of the mucosa that can be result in sinusitis, the removal of all foreign bodies is generally recommended, even when they do not produce symptoms. In rare cases, the foreign body may extrude spontaneously, but in general, the decision of whether to remove an intraorbital foreign body has to be made by the co-managing team. Presentation of the patient with visual compromise, ptosis, diplopia, orbital inflam-mation or infection mandates urgent removal.

Likewise, surgical removal is indicated for all organic foreign bodies because of the high rate of secondary complications. However, surgical exploration in case of inorganic foreign bodies depends on their location and the potential complications if left in place. For instance, 25 liter pot the access to anteriorly located intraorbital foreign bodies is relatively simple, and thus these should be removed. In posteriorly located foreign bodies, however, the risk of surgery may outweigh the benefits, so in the absence of significant orbital complications, these should be left untouched.With an estimated 50 million infections per year across many countries, Dengue is now recognized as one of the major public health problems worldwide. It is a mosquito-borne illness belonging to the genus flavivirus and consisting of 4 distinct serotypes, namely DENV-1, DENV-2, DENV-3 and DENV-4 . In majority of the cases, the illness is self-limiting with mild symptoms such as fever, rash and joint pain . However, this may predispose to a severe form  with infection with a different serotype . Today, dengue is endemic in more than 100 countries across Asia, Africa, America, Eastern Mediterranean, and West Pacific. Central to this is the enlarging habitat of its vectors, Aedes aegypti and Aedes albopictus. Aedes aegypti in particular, is highly adaptive in crowded areas; hence epidemics have been seen in cities with un-planned urbanization and overcrowding. Pakistan also had its share of dengue outbreaks in the recent years owing to the factors mentioned above. Epidemics have been reported especially in urban areas of Karachi and Lahore; situation worsening especially after monsoonal rains and floods. In October 2010, a total of 1809 cases were suspected out which 881 cases were confirmed of Dengue infection. In 2011, worst outbreak occurred in the country when more than 14,000 people were affected with dengue with over 300 deaths. Considering the current situation of Dengue virus and unavailability of data in Pakistan urgent attention and oversight is required to ensure effective preventive and curative program development. The objective of this study was to estimate the proportion of Dengue virus specific IgG ELISA among asymptomatic children between the ages of 1 year to 15 years, residing in an urban population of Karachi. When re-infected this population would potentially be at a higher risk of developing severe forms of dengue hemorrhagic fever. A cross sectional survey was conducted from September 2011 to February 2012 to estimate the prevalence of dengue virus. The study cohort consisted of children between one to 15 years of age. The study participants were stratified by geographical zone and age group. There were four zones  in the Garden area. The participants were divided into three age groups of 1 – 5 years, 6 – 10 years and 11 – 15 years. Seventy five children were included from each age group in each zone to ensure that the sample was representative not only 1 zone that why each zone was divided equally. Thus a total of 900 children were enrolled in the study and for the selection of respondents systematic random sampling technique was used.

After taking written consent from the parents/guardians, data was collected by research medical officers using a questionnaire, specially prepared for this survey. Information was collected on household socioeconomic status, medical history of febrile episodes including previous dengue infection followed by general clinical examination. Anthropometry height  and weight  was also performed. Blood samples were collected from the subjects and sent to Research Laboratory, Aga Khan University, Pakistan for determining complete blood counts and serum IgG antibodies for Dengue. Complete blood counts were tested using automated hematology analyzer .Dengue IgG antibodies was determined by Enzyme Linked ImmunoSorbent Assay , using Pan Bio Kits . Our study indicated that 46% of the population had been infected with dengue virus, making them susceptible to severe forms of dengue fever. To date, no study of this sort had been conducted from Karachi, Pakistan. Our study showed that Dengue IgG was found more in elderly children . This finding has also been reported by other researchers in their settings. Our study also showed greater preponderance of dengue IgG antibodies in males compared to females. Where reports suggest no significant differences associated with sex that might be different from Pakistan’s perspective owing to the fact that majority of the females remain indoors while males spend their maximum time outside. As mentioned previously, the dengue vectors are highly adaptable to any environment, hence it is probable for male children of such ages to become exposed to its habitat more often and contracting the virus. In our study, analysis revealed dengue IgG positivity to be more among lowest categories of socioeconomic position, comprising of 19% of the studied population. This was consistent with the study reported from Brazil. In our study, the finding was perhaps expected as Garden is a modern urban area with high rise buildings and inhabited by affluent communities.Employing strategies for water purification was also found to be important in the study, indicating a more likelihood to prior dengue infection in absence of water purification. In our analyses, 39% reported to purify water for consumption, using methods such boiling , filtering  and chlorination . It can be conceived that untreated water would be the possible niche for the Aedes mosquitoes to breed and multiply. Unique in this study is the positive association of stunting with IgG positivity . Our analysis also revealed a lesser likelihood of IgG positivity in presence of anemia and thrombocytopenia. These 3 conditions are pretty prevalent in this part of the world, each clinical correlate limiting us to offer any interpretation to its significance with IgG positivity. Some limitations are to note in this study. For instance we opted to collect information from a relatively affluent community of Karachi. Though previous studies on Dengue from around the world have indicated Dengue to be a threat for the urban areas, including squatter settlements would have provided a comparative picture showing proportional associations of positive IgG with overcrowding, sanitation and presence of domestic animals. The important and interesting aspect is to assess the serotype of the most prevalent dengue virus in these settings, as limited literature suggests DENV-2 and DENV-3 to be most prevailing in Pakistan.Lead is a naturally occurring metal that is used in many industrial processes, some of which lead to contamination of urban environments.

Lead deposition in urban areas is often atmospheric, originating from manufacturing, especially battery production, as well as in gasoline, and paint residues. Lead toxicities in people result in developmental, cognitive, motor, behavioral and physical injury, and for this reason, there is no acceptable lead level in the human system. In urban environments, lead may enter soils through atmospheric deposition, from dust near roadways, and from paint chips near buildings. Food grown in lead contaminated soils may be ingested, entering the consumer either directlyas transported particles containing lead or by absorption of lead salts in the crop consumed. Lead is persistent in soil. Since food insecurity is highest in large cities, recent efforts to produce food locally and in community gardens has increased, and lead ingestion must be examined carefully in urban food production systems. Attempts to alleviate food insecurity of impoverished citizens in cities by “guerrilla farming” activists may be putting consumers of such foods at risk, especially when farming on “Brownfield” sites previously contaminated with lead. Thus, those attempting food production in cities may be at risk for lead consumption and poisoning. Radish , a root vegetable, commonly grown worldwide, is consumed raw, raspberry cultivation pot as well as in a variety of preparations. Because radish grows rapidly from seed, it is preferred in school gardens where children can observe its rapid growth and development. All parts of radish are consumed, including foliage, the fleshy tap root, seed oils, and the immature seed pods. Ten species of radish are described in literature. The ability of globe radish  to absorb lead is known, and some varieties are “hyper-accumulators”. The variability of lead uptake in radish cultivars is not known. Lead salts occur in soil as oxides of metallic Pb or as salts that result from chemical reactions that may occur in soil. The solubility of lead salts in water is quite variable, from highly soluble lead nitrate  to practically insoluble lead sulfate . Lead is a divalent cation and is easily adsorbed onto clay colloids, or other cation exchange sites including organic matter, when it is in a soluble ionic state. Since lead reacts with oxygen and many other elements, there are likely many possible lead compounds and intermediates which may be present in contaminated soils.

In this study we present lead uptake data by five cultivars of radish growing in soils of two different textures, using two different lead salts as the lead sources.Soil was collected from 211 West Foothill Blvd, Claremont, CA , USA, which was a site known to be contaminated with lead. Multiple samples were collected along three linear transects of the site equidistant within a plot measuring 45 × 45 m. combined and homogenized. Samples were collected from the upper 20 cm of soil in spring of 2013. The site soil was dried, ground and sieved at the University of California Agriculture and Natural Resources lab  and analyzed for lead content using a nitric acid digest/extraction and detection by inductively coupled atomic plasma emission spectrometry  following procedures of Sah and Miller & Meyer and Keliher. Soil was passed through a 2 mm screen to remove rock and other large particles and blended with washed sand in a 3:1  ratio to improve bulk density for container culture of radish seedlings. Urea  was added at a rate of 1.25 g per 5” container containing 1.54 kg of blended sand and site soil to provide nitrogen for seedling growth. Five varieties of radish and one of mustard were obtained from High Mowing Organic Seeds  and seeded 1gm of each variety in each experimental unit . The study included radish cultivars “Cherry Belle”, “White Beauty”, “Purple Plum”, “French Breakfast” and “Rudolf” as well as the known lead hyper-accumulator Red Giant Mustard  Brassica juncea L. As a control, one of the radish cultivars  and RGM were grown in soil-less media composed of peat moss and sand  and fertilized with urea as above.

A growing part of and Product & Market Services  and FloraHolland Connect’s services is custom advice. Moreover, the flowers auctioned in FloraHoolland are not only limited to productsin Netherlands but also from Israel, Kenya, Colombia and etc. Whereas in KIFA, the flowers sold are mainly supplied by local growers. And growers can freely choose their dealing location and method, for example, many growers trade their products at Dounan Flower Market in wholesale method. In addition, small-scale production results in periodic intermittent supply. 5) Destination of sale. FloraHolland wants to maintain and reinforce FloraHolland’s position as the marketplace for European flower sales, maintaining its central position in the world’s leading areas for greenhouse horticulture is also its long development strategy. KIFA is one of biggest trade center in China, its buyers are almost from all of Chinese inner large-medium-scale cities. A small quantity of buyers is from Hongkong. Russia and Thailand sometimes take part in auction. 6) Logistics systems. FloraHolland has already established integrated systems for logistics, including inner logistical systems, logistical resources, and international logistical support. RFID, uniformed trolley resource, cool chain, potted-plant distribution, and air freight is being developed for supply and distribution chain from farm to auction market and from auction market to distribution at FloraHolland. Due to the restriction of external environments, KIFA now applies itself to establish collecting center in main planting area to decrease supplier’s logistics costs due to scale economies and re-design internal logistics distribution mode to improve allocation efficiency. 7) Standardization. The decoding standards of varieties, products, grades, and qualities have been built for many years at FloraHolland.

After merged in Jan. 2008, it will more rapidly achieve standardization in the whole chain of production and supply. FloraHolland have decided that all the trolleys, all the purchase and sales invoicing will be carried out the same standard for various locations and FloraHolland connect. Owing to standard scarcity of agricultural production in China, KIFA is now hammering at own intellectual property right of cut flowers. The past two years were turbulent because of financial crisis. Although sales of flowers and plants were generally not very sensitive to economic recessions,barley fodder system growth market shrank as a result of currency problems. FloraHolland is also striving to support its clients and members do business optimally in the current difficult circumstances. The number of suppliers and traders of FloraHolland did not grow in 2007. Turnover increased by 4.4%. This resulted in a total turnover of €3,892 million. The increase can be attributed to a 3.8% positive price trend and an increase in volume of 1% . Commission revenue just increased 0.4%, as a result of a reduced commission for the auction clock. The scale of suppliers and traders for FloraHolland has improved. These may be private companies and cooperative ventures, which operated as a major player in the market and were well placed to innovate. Number of employees of FloraHolland in 2007 deceased by 0.46%, at the same time, the productivity had 2.5% increase which ensured the volume increase. The year 2008 for China is a significant one because Peking Olympic Games was successfully held in Peking. So KIFA predicted sales, price and supply of cut flowers would have increased rapidly. But in fact sales, price and supply of cut flowers in China did not grow in 2008. Despite the difficult economic situation, 2008 ended with a hugely positive turnover for KIFA because of new business model. Annual turnover of KIFA increased by 53%, it resulted in a total of ￥163 million. The increase can be owed to an increase in volume 60%. Commission revenue increased by 53%, it resulted in a total of ￥16.4 million, which it is the first time that the revenue exceed the general costs . The number of suppliers and trades increased by 16% and 20% individually, as a result of the best price, the reliable quality, the decreased costs, the sufficient information and the increasing service level. The average number of transactions per day increased by 62% and the number of employees increased by 31%, it resulted in 60% increase in productivity in KIFA. 2008 was crucial and successful done one for KIFA, including operationally, commercially and financially.

However, lack of trading location  is a limitation to increasing the product supply. Considering the product category, it is difficult for KIFA to meet the buyers’ requirement by auctioning certain kinds of cut flowers while the products sold in FloraHolland cover almost all types of flowers and pot plants. The commission fee is also a noteworthy point. The commission rate in KIFA is 10.11% out of annual turnover, 8.65%greater than the commission rate in FloraHolland. Such a high commission is one of the factors that buyers and suppliers won’t choose the auction as their transaction mode.The sales of floriculture products for FloraHolland were a great success in 2007. Cut flowers, indoor plants and outdoor plants increased 1.74%, 8.78% and 9.54% individually . Exports from the Netherlands grew by 4.4%, thanks to the growth in Eastern Europe, France, the United Kingdom and Ireland. One attentive trend in FloraHolland is that sales through by connect had a great increase by 11.4%. Remote buying  has grown enormously in the past few years. Deals do not only buy in the auction room but also via an internet connection which means the location can be anywhere in the world. Another important fact is that the price of outdoor plants and indoor plants sold by connection is higher than by auction, which is different fact with the conclusion of Koppius et al. . From Table 3, we can also see that the revenue of selling indoor plants and outdoor plants is very large, about 38.5% out of total turnover. That means it is profitable not only through cut flower sales but also through indoor plants and outdoor plants sales. Although the sales of cut flowers for KIFA were a great increase in 2008, an important trend is that the ratio of bidding failure is increased. KIFA views this phenomenon in a positive sight. It means that the lower quality and outdated product should be washed out from the market. But on the other hand, it will depress the confidence of Chinese growers. Another difficulty for KIFA is that the batch size of cut flowers is also small at 180 units, at the same time, FloraHolland at 1800 units. Improving batch size of growers is a long-term and difficult task. Although auction is an old-fashioned deal method, it remains a strong selling instrument in foreign countries. Now FloraHolland is striving to intermediary services in direct transactions via the intermediary organization FloraHolland connect. But in China auction method emerged among some regions just in recent ten years, the cultivation of auction thought is a long-term process for growers and buyers.

Most of fresh agricultural auction markets in China were shutdown in past few years due to lower revenue. Through the comparison of operational goals and performances, we conclude that five operational strategy’s emphasis for developing Chinese flower auction markets as follows: 1) Transit of service strategies. Changing service thought is an important factor of Chinese flower auction markets. First of all, the auction market is not only the location for providing auction transaction, but an integral service provider for transaction, balance, logistics, information and direct sales. Second, providing customized service is crucial to keep participants loyal, so measures must be taken to decrease participants’ transaction costs to guarantee that growers and buyers choose auction as public platform for trade, such as providing various trade mode , excellent logistics and online payment. Finally, the auction market must be the knowledge center for participants. It can provide information on services and the very latest products, trends and sales concepts, so it can help participants to make their decisions. 2) Cultivation of participants’ network. Constructing participants’ network is a long-term and difficult process. The auction market must seek to achieve the highest possible price at the lowest possible expense for all members. The participants’ network is the best important assets for all of auction markets. As a result, it is very important to provide convenience, laborsaving, and happiness services for all members. An obvious trend is a growth in large scale flower and plant nurseries in China because of scale economies. The increases in scale take place predominantly through acquisition. The market may stimulate this and endeavor to increase the return because it is helpful to extend participants’ network. 3) Establishing standardization. Compared to traditional firsthand market, the auction market can provide uniform quality standard. Product quality is a high priority for auction market. The auction organization would offer the opportunity to more rapidly achieve standardization in the chain of production and supply. Doing this could greatly decrease the intermediate links and improve trading efficiency.

The standards of varieties, products, grades, and qualities are the first of all for Chinese auction market, which is the basis for well-doing operation. Owing to scarcity of fresh agricultural product standard, establishing standard is a difficult task for Chinese auction markets. 4) Clever mechanism design and avoiding some factors influencing successful auction. Clever mechanism designs are only very occasionally among the main keys to an auction’s success. Much more often, the keys are to keep the costs of bidding low, encourage the right participants to participate, hydroponic barley fodder system and ensure the integrity of the process. Some other factors are more important for Chinese auction market, such as setting right reservation price and commission rate, building clever disposal mechanism for lodge and bidding failure, and developing agent organizations for the small-medium growers and buyers. 5) Improving on operational performance continuously. The measurements must be brought into auction organization’s eyes, such as saving general costs for auction market, improving work efficiency, turnover, and service level, and increasing revenue and value added service. All these measurements require technology innovation continuously. Remote supply, remote buying, image auctioning, online sales systems, and direct sales, all of these new business models should be put into use through technology innovation. Rice  is the most important cereal crop in the world and it is the primary source of food and calories for about half of mankind. More than 75% of the annual rice supply comes from 79 million hectares of irrigated paddy land. Irrigation is an important practice in agriculture, the competition for fresh water in the development of urbanization, industry, leisure, and agriculture causes the decline of fresh water for irrigation. Water scarcity is a severe environmental limitation to plant productivity. Drought induced loss in crop yield may exceeds loses from all other causes, since both the severity and duration of the stress are critical.

Stress has been define as “any environmental factor capable of inducing a potentially injurious strain in plants”. Water is a major constituent of tissue, a reagent in chemical reaction, a solvent for and mode of translocation for metabolites and minerals within plant and is essential for cell enlargement through increasing turgor pressure. With the occurrence of water deficits many of the physiological processes associated with growth are affected and under severe deficits, death of plants may result. The effect of water stress may vary with the variety, degree and duration of water stress and the growth stage of the rice crop. Water stress during vegetative stage reduces plant height, tiller number and leaf area. However, the effect during this stage varies with the severity of stress and age of the crop. Long duration varieties cause less yield damage than short duration varieties as long vegetative period could help the plant to recover when water stress is relieved. Leaf expansion during vegetative stage is very sensitive to water stress. Cell enlargement requires turgor to extend the cell wall and a gradient in water potential to bring water into the enlarging cell. Thus water stress decreases leaf area which reduces the intercepted solar radiation. Rice leaves in general have a very high transpiration rate thus under high radiation levels rice plant may suffer due to mid day wilting. Rice plant can transpire its potential rate even when soil moisture was around field capacity.

The development of tissue culture protocols is one of the solutions to address these problems. In early reported regeneration via somatic embryogenesis in C. pepo. Due to the difficulties in obtaining and longtime culturing somatic embryos, alternative protocols for direct or indirect organogenesis have been studied. Direct regeneration in C. pepo was first described using cotyledon with attached hypocotyl as explant. A wide range of other C. pepo cultivars regenerate to the same extent  using the same technique. Brief sonication treatment stimulate shoot regeneration reported. In vitro shoot regeneration of a seedling-derived organ caused by prolonged seed storage period reported. The objective of this study was to investigate the effect of age of the explant, effect of important additives and subcultures to improve the regeneration from cotyledonary node explants of important zucchini type vegetable crop. The addition of L-Glutamine was very useful for adventitious shoot regeneration in C. pepo. The highest frequency of adventitious shoot regeneration  and the maximum shoots/buds regeneration  were achieved on MS medium containing BA, TDZ and 15 mg/L L-Glutamine at the end of second shoot induction. The shoot regeneration number per explants progressively decreased or callus formation with higher level of L-glutamine . The released nitrogen sources from L-glutamine provides a readily available source of nitrogen, the implication being that the formation of necessary carbon skeleton or the reduction of nitrate to ammonia is a limiting factor in the cells. Maximum multiple shoot enhancement was observed in Cucumismelo, Cucumis sativus due to the addition of glutamine. Our results showed that the improvement of in vitro multiple shoot buds/regeneration as well as improve the shoot number per cotyledonary node explants can be achieved by using BA TDZ with combination of L-Glutamine.

After 4 weeks of the culture the explants further transferred to the shoot elongation medium containing reduced concentration of BA 0.5 mg/L GA3 0.5 mg/L with 15 mg/L L-glutamine. For this combination was used for all the subcultures. During the subculture the newly shoot buds are formatted and also observed clustered shoots. Similar reports were reported in C. pepo. During the subculture rarely in vitro flowering are formed, precocious flowering is well known phenomenon in cucurbits. Interestingly we observed continuous new bud, dutch bucket for tomatoes shoot formation in the elongation medium and the same time older shoots are elongated. Maximum shoots production observed at the end of culture/end of 8th subculture 34 – 36 shoots/explant . However, without BA and L-glutamine in the elongation medium shoot produced are reduced.The process of introduction is clearly consistent with the spatial and temporal relations of the form of life. This link genotype is fixed and has the phenotypic expression of morphological variability biomorphs, features of its reproduction, ontogeny and decorative qualities. Crocuses are one of the most beautiful early-flowering plants. In the world there are about 80 species that are common in Europe and the Mediterranean in Asia. 19 species grow within the borders of the CIS. Crocus korolkovii Regel & Maw is a crocus  from the family of Iris or Iridaceae Juss. One of the representatives of mountain and foothill grasslands of Central Asia is Jungar Alatau. Crocus korolkovii was described in 1880 by two authors  on fees from the Northern foothills of Uzbekistan , included in the Red Book of Kazakhstan. Many species of the family Iridaceae grow in parks and gardens as an ornamental plant because of their beautiful colors. Some types of Crocus L. were used for the preparation of dyes, perfumes and medicines back in 1600 BC. F. Abdullayev  pointed out that saffron may be useful in chemoprevention of cancer in the near future. Morphological features of Crocus alatavicus Regel et Semen and Crocus korolkovii Regel & Maw in Tashkent conditions were studied by AH Sharipov. Canan Ozdemir studied the anatomical structure of the Crocus flavus Weston subsp. Anatomical studies on Crocus korolkovii Regel & Maw were not carried out. The purpose of the study is to introduce, identify and select the most decorative and resistant species, creating decorative and medicinal plantation crocuses in Uzbekistan.Or Saffron , corm almost spherical, up to 1.5 cm in height and 2 cm Chiron, with webbed unclear mesh, reddish scales. Leaves  appear during flowering, narrow-linear, grooved, with a white stripe down the middle. Flowers are solitary or in 2 – 5, with a funnel-shaped perianth of 6 identical leaves, adherent in a long tube.

The color of flowers is bright, yelloworange, outside shiny purple. Stamens three, they are half as long as tepals, with orange, not diverging from the tops of anthers. The fruit is oblong box, about 1 cm wide, appears on the surface only after maturation. Flowering is in February and May, fruiting in May-June. C. korolkowii introduced from the Pamir-Alai Range  to Tashkent . In the first year we studied bioecological features only plants under natural conditions. In the second year of the study studied phenology, flowering biology, breeding, seed production and the anatomical structure of the plant with the introduction of conditions. Phenology was studied by I.N. Beideman, the biology of flowering by A.P. Ponomarev, seed production by T.T. Rahimova. The anatomical work was carried out using fresh tissue samples fixed in 70% alcohol. The introduction of conditions tubers planted at 8 cm apart and 10 cm depth, with aisles of 40 cm. The vegetation of the underground parts of the plant began in the II-III decade of October. The diameter of the bulbs 1.5 – 2 cm, the number of roots 52 – 55 pcs., Root length 4 – 4.5 cm. The height of the underground parts of plants is 4.5 – 5.5 cm, sprout 4 – 4.5 cm length, width 0.5 mm .Regrowth of the leaves and the appearance of buds in C. korolkowii in Tashkent conditions observed in the second decade of January, February, sometimes depending on the weather conditions of the year. The earliest flowering noted,on February 14 the most later than 3 March. Flowering ends in II-III decade of March. Fruiting occurs in late April – early May. The end of the growing season occurs in the first half of May. The duration of the growing season is of 96 – 158 days .In nature, C. korolkowii blooms in February and March, in Tashkent under flowering phase had shifted to an earlier time . In the study of the biology of flowering C. korolkovii defined optimal humidity, air temperature and soil surface . In nature, C. korolkowii fruiting in May-June, i.e. in a phase of fruition in Tashkent had shifted to an earlier time . Under Tashkent conditions C. korolkovii seeds are formed in the second decade of April. The term of the formation of the seeds is about 7 – 8 days. 22 – 28 pieces are formed in each box. Seeds, 0.3 – 0.5 mm in size . Seed production figures are shown in Table 3.Samples of plants  were collected in the experimental section of the Tashkent Botanical Garden. The anatomical work was carried out using fresh tissue samples fixed in 70% alcohol. The base sheet cross-section is flattened, triangular, with obtuse angles. The surface of the keel smooth, rounded edges, the side edges of the sheet edge enhanced adaxial part of the concave. The epidermis thick-walled large-keel  & Figure 7.

Mesophyll keel consists of 3 rows of cells relatively small garden, which are located between two large and one small vascular bundle. Close vascular bundle consists of 20 – 25 vessels, and phloem, is a group of bundles of sclerenchyma cells. The side of the base plate consists of a single row of relatively small thick-walled epidermal cells of the epidermis, which is located under the 3 row palisade tissue. In both side portions are large by conductor bundle 3. Between the beams are located in the middle of the sheet winding with parenchymal cell walls. The middle of the sheet in a cross section clearly triangular, smooth wing surface side of the leaves are trifoliate-grooved has a similar structure to the leaf base, but differs in the number of vascular bundles , the size and density of palisade cells & Figure 8. Parenchymal cells in the middle portion occupy a large area . Groups of sclerenchyma cells above the beams, less thick. The top of the sheet is different from the base and middle of the following indicators: leaf blade narrow cuticular layer of the epidermis papillary, large-, palisade cells are large, elongated and arranged more densely, small vascular bundles sklerification. Thus, Crocus korolkovii strongly expressed palisade parenchyma in the base plate occupies a larger area than in the middle and at the top. Conductive beams sklerification less, the number of vessels in the beams more.In an amount of 1 – 5 flowers, tepals are yellow-orange on the outside  together with a tube with a streak of purple stain, lanceolate or oblong, acute or obtuse, 15 – 20 mm long, 3 or more times as long as tube. Stamens are 2 times shorter than the tepals, with orange anthers. Stigmas whole. Capsule oblong, 8 – 9 mm wide. The cross section of the stigma 3-lobed, curved oval shape. Small in size. Staminate thread slightly rounded with a recess, covered with rare or single-celled hairs. Staminate thread consists of 4 – 8 rows of parenchyma, located in the center of one vascular bundle with two small vessels.A cross section of anther consists of two layers, the inner and outer epidermal fibrosus. Epiderm is papillary larger – & Figure 11. The tube is at the top of the 6-lobed, parenchymal. The parenchyma consists of 3 – 7 rows of crushed cells of different sizes  & Figure 10. In mid-parenchymal cells are numerous small vascular bundles with 5 – 8 vessels. The epidermis is of the tube small cell. In the middle part of the perianth tube is oval, slightly winding  & Figure 10. Thin-walled parenchyma small cell partially destroyed it. In the center there are several lined parenchyma vascular bundles, non-oriented arrangement. Thus, three-lobed stigma, its structure parenchymal, perianth tube in a cross section of triangular shape, smaller than the number of C. sativus L. conductive beams 21 – 22. Perianth walled parenchyma with small vascular bundles.Human activities are the primary drivers of dynamic agricultural systems, which in turn determine the structure and function of agroecosystems. Human activities in agroecosystems are the result of attitudes derived from a combination of ideas, motivations, and experiences. Thus, it is necessary to integrate humans’ activities, which are governed by human perceptions, value systems, cultural traditions, blueberry grow pot and socioeconomic activities into agroecosystems. Achieving sustainable agroecosystems often depends on curtailing or managing human actions that either sustain or degrade the desired agroecosystems. Therefore, the human component of agricultural systems is central to their sustainability, and one of the most important aspects of the human component is perceptions of circumstances and environment. In other words, the human-agroecosystems relationship is influenced by the human worldview—a person’s perception of the world and their place in it.

Human perceptions shape the decision-making processes that lead to the actions that affect agroecosystems and ultimately determine whether production and conservation goals are harmonized in the development of agricultural systems. Because of this intrinsic link between perceptions, decisions, and actions, gaining an understanding of human perceptions is a critical first step to achieve sustainable agriculture. The structure and function of agroecosystems are closely linked to human perception. However, the relationship between perception and behavior is not always linear. Various factors affect the relationship between perception and behavior, such as socioeconomic and cultural references that influence how individuals act. On the other hand, ecological realities can also affect how farmers act with regard to agricultural practices, which in turn will form site-specific agroecosystem setting. There has been insufficient research performed to reveal how traditional and modern societies exert their perceptions and values upon the ecosystems they live in and how they manage to practice sustainable environmental management. Yet, understanding the relationship between human and ecological phenomena is essential. The evolutionary development of agroecosystems through the process of species introduction, selection, and substitution depend on how the rural people living within the system perceive their environment.

Food waste from household consumption contributes largely to food loss as demonstrated in the study of Garcia-Herrero et al. . Besides measures for reducing production of food waste, methods for its valorisation is important. Urban farming is an example of alternative food production systems that provides locally produced food, thereby contributing to a reduction in long-distance transportation of foodstuffs into cities. However, for effective food production in cities, where possibilities for cultivation in soil are scarce, alternative production systems with low area requirements are needed. One solution to this constraint is to turn to hydroponic farming, where the food crop is grown directly in a nutrient solution , minimizing the space needed for cultivation. These production systems enable the possibility of farming in varying system designs such as horizontal, vertical or in several layers, and in diverse locations such as in basements, on rooftops and in containers, are thus attractive and promising systems to explore further in an urban context. Hydroponics have been used in traditional large-scale production of vegetables over the last three to four decades, however the nutrient supply is almost exclusively based on industrially manufactured, mineral  fertilizers that challenge the pursuit for sustainable and renewable nutrient and resource loops . In Sweden, selected organic wastes, including food waste, are largely used for biogas production, with a nutrient-rich liquid digestate remaining as the by-product after the anaerobic digestion process. Using this anaerobic digestate as the nutrient solution in hydroponic cultivation systems could pave the way for a circular urban food production system as well as valorising food waste. Evidently, the use of recycled and biobased fertilizers constitutes an advantage from an environmental perspective compared to the mineral fertilizers used in conventional hydroponic production.

One major point of attention is however the close contact between the crop and the nutrient solution in hydroponic production systems. It is therefore paramount to primarily investigate and establish whether the anaerobic digestate is microbiologically safe to use for food production . In Sweden,flood and drain tray anaerobic digestate based on selected waste originating from the food and/or feed chain can be certified as biofertilizer according to SPCR 120 , a Swedish national regulation that needs to meet the criteria of the EU-regulation EC No. 1069/2009 regarding the treatment of biowaste . In order to fulfil the requirements for this certification, the feedstock used in the biogas process is initially hygienized by heat treatment . Previous studies have concluded that the combination of thermal pre-treatment followed by anaerobic digestion is successful in reducing Salmonella, Enterococci and Escherichia coli to acceptable/non-detectable levels as required by EU-regulation . However, while the presence and survival of these specific bacteria have been closely investigated, more in-depth studies into the overall biosecurity and pathogen content in anaerobic digestate from biowaste are encouraged . Regarding extended utilization in shorter nutrient cycles such as a hydroponic setup, which omits the natural processes occurring in contact with organic compartments such as soil, a thorough risk assessment becomes even more relevant. In a pilot study preceding the present work, three different, geographically distributed biogas plants in Sweden were sampled and the microbiological quality of the biofertilizer studied. In addition to the requirements in the certification, control of spore-forming species and presence of antibiotic resistance were conducted. The results confirmed that all formal criteria were met, however, biofertilizer from all plants had unsanitary levels  of the food-borne spore-forming pathogen Bacillus cereus . This is in agreement with a previous study conducted on the hygiene aspects of biofertilizers where high levels of Bacillus spp. were detected , and it was deduced that neither the hygienization treatment nor the following anaerobic digestion affected the number of Bacillus spp. The overall scope of this study was to assess microbial risks related to the use of SPCR120 certified anaerobic digestate as a nutrient source in the hydroponic production of vegetables. The microbial viability and activity in the biofertilizer, before use in a hydroponic system, was initially studied over time with cultivation-based viable count, and cultivation-independent isothermal calorimetry.

Challenge testing with the three major food-borne pathogens B. cereus, Salmonella enterica ser. Typhimurium, and Listeria monocytogenes was also performed to investigate the biofertilizer’s susceptibility to contamination and ability to support microbial survival and growth. For assessment in hydroponic production settings, samples of circulating nutrient solution, based on either biofertilizer or inorganic fertilizer, were collected during a growth cycle in a greenhouse experiment and 16S rRNA gene amplicon sequencing was used to study the bacterial community composition over time. IC was utilized to measure the heat developed over time in samples with  or without supplementation  of nutrients. The heat developed is a result of metabolic activity of the organisms in the sample, and it was thus utilized as a cultivation-independent method of investigating microbiological viability and/or growth, an asset when assessing complex samples that may contain viable but not culturable cells. It also has the advantage of monitoring microbiological viability and growth without the introduction of bias that the agar plates selected in traditional standard plate count may account for, and the calorimetric measurement also gives an on-line and continuous output. At the same time, VC analysis was performed. Obtained VC results of samples without supplementation indeed pointed towards an actively growing microflora present, since a rich number of colonies was obtained on the plates at each sampling point. Contradictory to these results, there was no heat generation detected within the same samples  when utilizing IC. The IC thus provided a presentation of the microbiological state of the biofertilizer without the bias that the introduction of nutrients from an agar plate may introduce. Fig. 2A and B shows the analyses from VC and FC after supplementation of BHI broth, and from IC after supplementation of BHI broth and glucose to the biofertilizer during the full duration of the accelerated microbial activity assessment experiment. As can be seen in Fig. 2B, the supplementation of glucose generates no metabolic activity. Regarding the supplementation of BHI broth, the first supplementation generates a heat production of around 100 J, with the following two supplementations generating a heat production of around 50 J, and the last two supplementations generating around 25 J. If it is assumed that the headspace of the vials is filled with air each time a vial is opened, the first supplementation generates more than the 50 J that aerobic metabolism can give, so this part does include anaerobic processes, but the lower heats indicate that the processes may be mainly aerobic.

Since the last two supplementations do not reach 50 J of heat produced, it is hypothesized that maximum growth capacity in the matrix has been reached, possibly due to restrictions in water activity or antagonistic behavior within the microbial community. The corresponding VC  shows a 2.5 log increase in CFU mL− 1 after the first supplementation, and the following supplements induce no substantial increase in growth with either VC or FC . When performing microbial food safety risk assessments, not only presence/absence but also levels or concentrations of microorganisms, are valuable pieces of information needed to be able to evaluate food safety risks. From these results it appears however that the heat produced from metabolic activity is challenging to correlate with the number of CFU mL− 1 and cell count mL− 1 . According to a review by Braissant et al., the heat production of creating a cell should be rather constant, and it is also stated that if cell lysis takes place, this will cause a discrepancy between the heat generated and cell count . The fact that the sample contains a complex, mixed microbial community complicates the interpretation of the heat flow and heat generated after multiple supplementations, as the metabolism of different bacteria will generate different heat flows, and also there might be a succession of bacteria or a decline in some species caused by metabolites produced by the predecessor. This hypothesis was further hinted at when the visual inspection of the agar plates from the VC indeed revealed varying colony morphology and appearance after the different supplementations, andalso revealed some colonies exerting antimicrobial behaviour on their surroundings . This study has highlighted the difficulties of correlating VC with calorimetric data, which has already been observed in studies of other complex natural matrices . However, it can be stated regarding both the calorimetric data and the VC that while bacteria are indeed present in the biofertilizer, no metabolic activity is generated until the supplementation of an external complex nutrient source. As seen in Fig. 2A, the supplementation of glucose did not lead to subsequent metabolic activity while BHI broth did, indicating that an accessible source of carbon was not the  limiting factor for microbiological activity, but potentially a combination of a carbon source and necessary trace elements that the BHI broth provides. In terms of the microbiological safety of utilizing this biofertilizer for hydroponic vegetable production, it is thus essential to avoid the addition of a nutrient source that can allow for the establishment of pathogenic bacteria. Although cultivation-based VC is a commonplace method of evaluating food safety in a matrix, it may allow for the introduction of false negative results when viable but not culturable cells remain undetected. As presented in this study, it might also produce false positive results when the agar plates provide the nutrients necessary to allow for microbial growth, nft hydroponic while the biofertilizer on its own does not provide the necessary factors for growth, rendering its natural microflora dormant. Studying the microbial community of complex natural matrices is in general difficult as several parameters of the matrix and its microbial processes are unknown.

As pointed out by Wads¨ o in a work using IC for studying the microbial activity in soil , IC is useful due to heat measurements being non-specific, and might thus be a preferable tool when investigating the total sum of complex microbial activities within a natural sample. Although IC is insufficient on its own for determining the microflora, separating the processes of one microorganism from the other, or separating microbial metabolic activity from microbial growth, IC and VC are excellent complementary tools when investigating the presence, viability and activity of complex microbial communities in their natural matrix. Microbial contamination of biofertilizer in hydroponics could cause serious consequences as the biofertilizer is recirculated and the plants are exposed to it during their entire growth cycle. A previous review, assessing the internalization ability of bacteria present in nutrient solution in hydroponic setups, concluded that present pathogenic bacteria and viruses internalize readily and more frequently compared to soilbased systems . This endorses the need for a deeper and more systematic understanding of how pathogenic bacteria would behave in the biofertilizer, in case of a contamination scenario, to assess the risks of using biofertilizers from anaerobic digestate for food production in hydroponic systems. As Bacillus cereus occurs naturally in the biofertilizer, and Salmonella and Listeria are able to internalize into growing crops , a challenge test experimental setup was performed to simulate contamination with the food-borne pathogens S. enterica serovar Typhimurium, L. monocytogenes and B. cereus, and assess their establishment, survival and growth in the nitrified biofertilizer over time. Fig. 3 shows the outcome of the inoculation of the food-borne pathogens B. cereus, S. enterica and L. monocytogenes in the biofertilizer. In the two biological replicates performed, S. enterica and L. monocytogenes were no longer detectable through selective plating within 48 h of incubation. Throughout the two biological replicates, B. cereus was steadily present in the control of non-inoculated biofertilizer and estimated at 1 log10 CFU mL− 1 . The biofertilizer inoculated with B. cereus decreased to these levels within 24 h after incubation. Previous microbiological controls at three Swedish biogas production plants had shown that the biofertilizer product after hygienization and anaerobic digestion contained up to 4.3 log10 CFU B. cereus per gram of biofertilizer . This level should be given attention, since the majority of food-borne outbreaks caused by B. cereus have been implicated with concentrations of 5–8 log10 CFU g− 1 of food of emetic toxin producing B. cereus. Occasional outbreaks of both emetic and diarrhoeal B. cereus illnesses with even lower levels have also been reported.

In fact, the stage of the growing period seems to be an influencing variable. In a study involving the hydroponic growth of tomato , wilt due to Fusarium was reported to be most severe in the intermediate or late growth stage of the growing period . For this reason, the duration of the trial was longer than initially expected, so the size of the plants increased and with it their nutritional requirements. This situation led to an imbalance in the aquaponic systems which were unable to provide adequate levels of nutrients to the plants. As a consequence, these plants suffered a nutritional deficit that made them more sensitive to Fusarium wilt . Hence, the hydroponic plants being better nourished, could be more resistant to biotic or abiotic stresses. This effect was also observed by the fact that the disease severity was lower in the plants near the entrance of the water with the nutrients , despite being closer to the inoculated plants . As is the case of Pythium aphanidermatum. This produced 100% mortality in spinach that was grown in water at 30 ◦C, but 0% of mortality was observed in crops that were in water at 20 ◦C . As another example, Pythium dissotocum caused the wilting of 100% of the plants when the water was at 30 ◦C compared to the 69% that wilted when the water was at 20 ◦C . These differences in disease prevalence and severity are likely related to optimal growth temperatures for these pathogens, with higher infection and mortality rates as a result of water temperatures being more favourable for pathogen development . In our study, the maximum values of water temperature reached 25.1 ◦C in the aquaponic system and 26.8 ◦C in the hydroponic system, therefore below 30 ◦C. However, neither Fol nor P. cactorum were harmful to goldfishes in our tests since no mortality or disease symptoms were observed. In relation to the water chemical parameters, aquaponic systems remained within the limits recommended by the FAO ,ebb and flow table with a pH between 6 and 7 and a nitrate concentration between 5 and150 mg L− 1 , in order to maintain the well-being of the plants, fish and bacteria.

The electrical conductivity was kept close to 1500 μS cm− 1 in the hydroponic systems, not exceeding 1700 μS cm− 1 . Though the recommended pH in which the plants have a greater availability of nutrients is between 5.5 and 6.5 , it was kept slightly over those values in order to maintain conditions similar to aquaponic systems. Further studies are required to confirm higher suppressiveness in aquaponic systems compared to hydroponic systems, trying to maintain an adequate balance in the contribution of nutrients in each system. The study of several pathosystems could help to confirm the potential suppressiveness in aquaponic systems. Likewise, it would be interesting to take into account different types of fish, such as tilapia, which is fequently employed in aquaponic systems. Sustainable production of quality food under premises of circular economy reducing the flow of resources out of the system is crucial for ensuring food security while maintaining non-renewable resources such as phosphorus and reducing environmental impacts of agricultural practices . This is particularly relevant in areas of increasing population such as part of the Mediterranean basin.In this sense, initiatives that urge the development of policies, missions and incentives to spread circular economy practices, in particular in food production, throughout the world are increasingly abundant and insistent . Intensive early production of horticultural products is not only important for providing quality food out of the typical growing seasons but also crucial for ensuring economical sustainability of horticultural farmers due to the high prices of these early products. A paradigmatic example is early production of strawberry which, in the European Union, is mainly located in Southern Spain, concretely in the province of Huelva. This crop is a powerful economic engine for this area, comprising about 94% of total production in Spain . The total area dedicated in Spain to strawberry production in 2018 was 6603 ha, yielding 334,767 t of fruit, most of the production being destined to the international markets . In 2018, this exportation generated a value of 461.3 million €. The progression of the prices of the fruit shows a decline throughout the campaign, so that the initial values  condition the subsequent prices. According to this, early production in these agrosystems is critical in order to guarantee their profitability.

In conventional horticulture, strawberry is usually produced in a monocropping system, i.e. it is consecutively grown in the same field plots year after year, which increases the risk of soil borne diseases , making soil disinfection a necessary practice . Hydroponic production has demonstrated to be an interesting option due to its independence from soil microbiological status, while required minerals are applied to plants with fertigation. In this context, the soilless production, as in other intensive horticultural areas, in Spain is progressively increasing and currently amounts to near 6% of the total production surface in the main strawberry production region. However, other authors report that the influence of substrates on fruit quality and yield is less relevant than the effect of strawberry cultivars . Although soilless production may enhance the resource efficiency, horticultural systems demand high rates of external inputs, in particular, water and nutrients. In this regard, the EIP-AGRI Focus Group on Circular Horticulture concluded that aquaponics is emerging as one of the most important areas of sustainable agriculture which meets the philosophy of circular economy . These systems not only decrease the need of external nutrient supply but also reduce the overall water discharge and increase water use efficiency in agricultural products. Aquaponics is a production system that synergistically combines the simultaneous growing of plants in soilless media  and fish in recirculating aquaculture systems . Plants improve their growth by using metabolic waste from fish and unconsumed feed, which are transformed by a bacterial community into easily assimilated nutrients , reducing discharge to the environment and extending water use. Aquaponics has less environmental impact than conventional aquaculture and agriculture.This production system may have higher productivities and less resource consumption than conventional land-based systems . Therefore, aquaponics is a production system aimed at reducing inputs as well as minimising pollution whilst maximising production efficiency and stability, hence increasing revenues . Strawberry cropping in aquaponic systems may be an interesting alternative since it is a profitable crop when early produced which can be managed under soilless conditions.

In fact, soilless production is gaining interest as mentioned above to avoid the risks ascribed to monocrop production on soil. Nevertheless, very few studies about strawberry aquaponic production are available, flood table and mainly focus on operational factors such as substrates used or fish densities employed . Both the early strawberry production and the quality of the fruit, which are crucial factors affecting crop profitability, have not been assessed in previous research. In this regard, it is crucial to know how the root anchoring system , whether bare roots or inert growing media such as the widely used rockwool may affect crop traits. Thus, this work aimed at the evaluation of the yield and quality of the combined early production of strawberry and tench , by means of coupled aquaponic systems. In them, commercial hydroponic bands were employed, and the differences of using or not a rockwool substrate were assessed as a relevant aspect which may affect crop performance, quality, and precocity, as well as resource consumption in the system.For this study, three identical coupled aquaponic systems were installed inside a greenhouse located at the School of Agricultural Engineering , encompassing a total surface of 36 m2 . Each system was composed of a 1 m3 cylindrical fish tank, where water was aerated using a 400 L⋅h− 1 air pump for ensuring a correct level of oxygen dissolved in the water for the fish. Water temperature was controlled by means of a 300 W heater . From the fish tank, water was conducted by gravity to a handmade PVC biofilter of 50.26 L capacity , filled with ceramic rings as filter media. Then, water was divided into two NGS  multilayer channels with 1.5 m length and 0.8 m separation, with 12 holes per channel to hold plants . The NGS is a modification of the nutrient film technique  hydroponic system, consisting of a series of interconnected layers, which favour small cascades that support the increase of oxygen availability and elude length limitations in NFT channels . NGS’ multi-layer DUO is specially designed for strawberry crops, and it is composed of 3 polythene bands forming a superior level, with 2 lines of holes following a zigzag pattern to hold the plants, and two inner levels to room the root system and to collect the nutritive solution while favouring aeration . At the end of both hydroponic lines, water flowed down into a 100 L sump tank, where a single submerged water pump was located  in order to return the water to the fish tank, closing the loop. With the aim of facilitating the growth and colonization of nitrifying bacteria inside aquaponic components, the systems remained in operation, without fish or plants, for a period of six weeks. During this time, ammonia was artificially introduced in the tanks to speed up the process. Tench  was chosen as fish species for this aquaponic prototype, since it is fully adapted to the Iberian Peninsula’s climate and is recognized for its great resistance to changes in water quality in extensive and intensive regimes , being an adequate candidate for aquaponics production systems in this area .

The study was started with an initial population of 366 tench fingerlings, counting up a total biomass of about 2100 g. The fish were provided by the Regional Aquaculture Center “Las Vegas del Guadiana”, a public company belonging to the Junta de Extremadura, located in Villafranco del Guadiana . The acclimatization phase began at the end of November and consisted in the introduction of a fish biomass of 700 g in each tank. The number of specimens in each system was homogenized, leaving 122 fish  in each tank. Low density of fish was selected according to the recommendations of Villarroel et al.  and to simplify systems management. The cultivar of strawberries used was ‘Primoris FNM’, a short day cultivar, which begins fruit production about eight or ten days before most of medium cycle varieties. Runners were acquired from Fresas Nuevos Materiales, S.A. , after having gone through a high-altitude nursery to meet the low temperature requirements for the start of flowering, in the same conditions as theseedlings that are usually planted in crops in southern Spain. Half of the runners were placed in a seedbed with perlite and the other half in rockwool blocks. Once the first three leaves appeared, the seedlings were transplanted to the hydroponic lines, after elimination of perlite with running water. The study started from a total of 72 strawberry seedlings, of which 36 plants did not use any substrate and 36 were established on rockwool’s blocks. The strawberries were transplanted into the aquaponic two days after the introduction of fish, in order to ensure adequate nutrients contents for plants. Distribution of plants according to the substrate type followed a random blocks pattern, as it can be observed in Fig. 2. Each of the fish tanks was connected to two hydroponic lines and each of the lines contained two blocks of 6 plants with different substrate types . The development of the plants was monitored throughout the crop cycle, weekly recording different parameters regarding leaves, flowers and fruits. The width and length of the leaves were measured, as well as the chlorophyll content in old and new leaves using a SPAD-502 chlorophyll meter . In addition, a count was made of the flower buds, number of flowers and fruits and weight of fruits per plant. Regarding strawberry quality parameters, immediately after harvest, the firmness of the fruit was analysed using a PCE-PTR 200 Forge Gauce penetrometer ; and soluble solids were measured using a hand-refractometer RHC-200ATC applied to fruit juice.

Matuschke and Quaim  analyzed the impact of social networks on the adoption of hybrid wheat in India and concluded that the results from a social network study could also provide extension agencies and agents with a new set of diagnostic tools that could fit well with the new extension emphasis on participatory and demand-driven extension approaches. However, research on the role of social networking in seed and information exchange on stress-tolerant rice varieties among rice farming households/individuals and also through a gender perspective is scant. By gaining awareness of existing information on exchange routes, information providers can act on information opportunities and make changes to information routes to improve the delivery of information services . It is now increasingly recognized that information on agricultural innovations diffuses through social networks rather than being freely available in the village. We adhere to this view in studying the role that social capital may play in facilitating information exchange among rural households. Moreover, the roles of other end users of technologies, especially poor women farmers and their potential roles as key agents of change, can be tapped to accelerate the dissemination of rice and rice-related technologies. In 2009, the International Rice Research Institute  in collaboration with national agricultural research and extension semination of submergence-tolerant varieties” in six Southeast Asian countries frequently affected by typhoons and severely affected by floods, namely, Vietnam, Thailand, Cambodia, the Philippines, Indonesia, and Lao PDR. Within this project, a case study on “Seed and information exchange through social networks among men and women rice farmers” was conducted. This case study explored and compared the structure of information exchange among men and women farmers who were involved in PVS on submergence-tolerant varieties in pilot communities in Lao PDR and Indonesia.

The study also investigated social networks by gender in order to gain greater insights into how gender differences influence the effectiveness of social capital in facilitating information exchange. In particular, dutch buckets this study examined the factors that affect the intensity of acquired social networks at the household level, while accounting for gender differentiation. Social concepts such as social networks and social capital have received a lot of interest when exploring the potential contribution of personal relationships in technology uptake. Social capital is deemed as important as other forms of capital such as financial, human, or natural. Networks facilitate communication, coordination, and the provision of information on the trustworthiness of individuals. Social networks can serve as a form of social capital—an important intangible component of individuals’ and households’ asset portfolios. Gender analysis in Asian rice farming reveals that women in Southeast Asia contribute significantly in rice production and post harvest operations. Although labor participation in rice production varies by country, production systems, and other factors, women contribute about 46% and 60% in Indonesia and Laos, respectively . In Laos, women took over the traditional roles of men in rice farming, in which more than half of the rice farming activities such as transplanting, weeding, harvesting, and post harvest are dominated by women . Similarly in Indonesia, women do most of the transplanting, weeding, and harvesting work . Thus, women are seen to have a crucial role in shaping the rice economy of Laos and Indonesia. Moreover, women do not just contribute to the physical assets of production but more importantly they seek new information and technology. Due to gender differences in roles and needs, men and women have differences in their selection criteria for rice varieties in the specific submergence prone areas . Although returns to men’s and women’s social capital may be identical, the responsiveness of household welfare to women’s social capital is higher . Rural women usually have less access than men to information and new technologies . They suffer from limited access to resources, markets, training, and decision-making opportunities. As a result, women seek formal and informal networks to cope with the shocks and to make sure that their views are represented, particularly if formal rules limit their participation . Their lack of access to information and formal networks deprives them of their potential capacity to make informed decisions in effectively managing their farms and selling their farm products. Identifying the role of social networks and the factors affecting them has been investigated in the literature under various methods. This type of research is placed under the umbrella of social network analysis . The recent literature on social network analysis supports evidence that social networks play a crucial role in information and innovation dissemination. Hence, knowing more about networks and their role will be beneficial for policy formulation.

When an individual decides to join a network, he/she has an expected utility that depends on some of his/her socioeconomic characteristics. This expected utility is assumed to be positive, which motivates individuals to join a network. Each individual has the choice of being connected to one, two, three, and more relatives or friends who constitute his/her “acquired social network.” The intensity of the acquired network is therefore represented by a series of discrete household choices that could follow a Poisson or negative binomial distribution. Following Katungi et al.  in a similar study, we consider that the intensity of acquired social networks can be modeled as a series of discrete household decisions that sum across an aggregation of choices to a Poisson or negative binomial distribution. While the Poisson distribution assumes equality between the conditional mean and variance, the negative binomial is more suited to data exhibiting over-dispersion. Identifying the role of social networks and the factors affecting them has been investigated in the literature under various methods. The recent literature on social network analysis supports evidence that social networks play a crucial role in information and innovation dissemination. Hence, knowing more about networks and their role will be beneficial for policy formulation. When an individual decides to join a network, he/she has an expected utility that depends on some of his/her socioeconomic characteristics. This expected utility is assumed to be positive, which motivates individuals to join a network. Each individual has the choice of being connected to one, two, three, and more relatives or friends who constitute his/her “acquired social network.” The intensity of the acquired network is therefore represented by a series of discrete household choices that could follow a Poisson or negative binomial distribution. Following Katungi et al.  in a similar study, we consider that the intensity of acquired social networks can be modeled as a series of discrete household decisions that sum across an aggregation of choices to a Poisson or negative binomial distribution. While the Poisson distribution assumes equality between the conditional mean and variance, the negative binomial is more suited to data exhibiting over-dispersion. This SNA study uses cross-sectional data gathered through focused household surveys of rice farming households involved in the PVS trials under the project “Dissemination of submergence-tolerant rice varieties in Southeast Asia” implemented by IRRI in 2009. Data were collected by social scientists from farmer-cooperators in Indonesia  and Lao PDR  who were also cooperators of PVS at key sites. These key sites are located in the province of West Java, Indonesia, and in the provinces of Khammouane and Champassak in Laos. In this particular study, accumulation of social capital through social networks received much attention as most of the seed and information exchange in studied areas are produced in an informal mode.

To measure the intensity of participation in social networks of the farmers, the dependent variable is defined as the number of trusted friends to whom the household can talk closely or approach for any problem. This definition of a social network excludes relatives because they constitute a “given social capital whose formation may be beyond the influence of the decision maker” . Instead, the number of relatives of a farmer in the village was included as an independent variable to serve as a proxy for social capital endowment. Household characteristics such as age, gender, education, and household size are factors that might affect farmers’ social networking behavior. The size of social networks and frequency of engaging in different kinds of information exchange and village activities largely influence the social capital of an individual. Social capital among men and women varies for the two countries as the accumulation of social capital is also dictated by gender roles and culture for each country. As shown in Table 4, grow bucket social networking and information exchange in Indonesia and Lao PDR are done mostly with friends within the village, where male farmers for both countries have a larger social network than female farmers. Lao men and women also rely heavily on their relatives within the villages. The number of relatives and friends of the farmers outside the village are generally higher in Indonesia than in Lao PDR, especially among women. These results reveal that male farmers are more mobile than female farmers in Indonesia. Because of customs, Indonesian women farmers do mostly reproductive activities, which limit them in having contact with other people outside their village. In contrast, in Lao PDR, there seem to be no differences between males and females in terms of mobility. Seed information exchange. During the survey interviews, male and female farmers were also asked about their seed information exchange. In Indonesia, both men and women farmers rely on their friends and neighbors within the village for seed information. Male farmers also mentioned co-farmers within the village, extension agents, and formal groups as their other main sources of information. None of the male Indonesian farmers received any information from their wives. Eleven percent of the female farmers mentioned their spouses as additional sources of information . Membership in formal organizations. Most of the farmers in Indonesia and Lao PDR belong to a formal group. Women are surprisingly actively involved in organizations, which are mainly farmers’ organizations, credit groups, and women’s groups. This means that women are now recognized as part of the workforce in the community. However, trends in civic engagement still show that few women are privileged to have access to different sources of information such as newspapers, printed publications, agricultural programs on radio and television, attendance at training events or seminars, and communication with extension agents. In some civic activities such as the use of modern technology such as the Internet and cellular phones, women in Lao PDR more frequently use them than men. However, it is important to note that these women are few in number and are mainly female household heads and wives of village leaders who have somewhat the same access as men farmers.

Involvement in social activities. Involvement in social activities of men and women farmers is still based on gender roles. Indonesian male farmers are expected to be in their mosque more frequently than women. In Lao PDR, where women are expected to give alms to the monks and offer prayers, women are seen in their temples more frequently  than men. Moreover, since market places are where the households sell and buy food and other items, more women are seen in these places than men. Women’s role within the households consumes most of their time; thus, they do not have much time compared with men to go to hang around places to chat and drink with their friends and neighbors after work. Also, more men attend village meetings as they are traditionally the decision-makers in their households and in their communities, particularly in Indonesia; whereas, in Lao PDR, both men and women farmers have the privilege to attend village meetings . Flow of information. Aside from sources of information, farmers were also asked whether they were passing along the information they received about new varieties. Male and female farmers from both countries usually pass along the information they receive to their friends and neighbors within the village with whom they can regularly talk because of their proximity to one another. In Indonesia, where women are more constrained to their houses to do more reproductive activities, the information they receive is passed along only to the members of their households, friends, and neighbors within the village.