Category: hydroponic agriculture

The main sources of anthropogenic global warming, in order of importance, have been identified as electricity generation, land-use changes, agriculture and transport . In the fight to reduce the greenhouse gases attributable to these human activities the development of accurate systems of measurement of these emissions has acquired great importance.In the field of accounting there have been abundant attempts to measure and value the impact of human activity on climate change. For example, sustainability accounting aims to provide stakeholders with a set of tools for addressing environmental,social and economic concerns ; full cost accounting seeks to capture more fully the social and environmental consequences of economic activities; and, carbon accounting provides procedures for calculating the amount of carbon emitted by different sources or the amount stored .However, evaluating the impact of human activities on climate change represents a considerable challenge in accounting given the absence of a globally accepted scheme capable of measuring systematically the interconnection between nature and economics.

In the traditional accounting framework the environmental impacts of human activities are considered as “externalities” , their exclusion resulting in biased information. The expenses recorded in financial databases appear too low as some costs are passed on to external parties, and so artificially low costs and prices are disclosed .In short, measuring greenhouse gases attributable to human activities is a way of reducing human impact on climate change. But emissions and other environmental impacts are still given no consideration in traditional accounting and,therefore, any related costs are valued at zero in traditional financial statements.One way of demonstrating that zero is not the right value for externalities is to analyse how they interrelate with economic performance. Despite considerable advances over the last twenty years in integrating economics and environmental issues, the valuation and association between their respective performances remainin conclusive .For instance, some authors report a positive influence of a firm’s environmental performance on its financial performance,claiming that a sustained improvement in environmental performance enhances financial outcomes.By contrast, others report just the opposite, with a better financial performance being associated with a poorer environmental record.

Finally, a third group of researchers argues that no clear pattern emerges in the relationship between economic and environmental performance.These differences can be attributed to at least three reasons. First, the field lacks, as discussed above, a globally accepted system for measuring the environmental impact of human activities, with previous research relying heavily on firms’ financial data and failing to provide a true account of the economic impact of the environmental externalities of their activities.Second, these studies have applied an array of different measures of environmental performance that are prone to give a variety of results and conclusions.Additionally, most use proxies of environmental impact rather than a specific measure. For example, Henri and Journeault built indicators from firms’ survey responses while Déjean and Martinez and Jacobs et al .  constructed them from firms’voluntary disclosures, the weakness being that these disclosure are typically made so as to influence stakeholders via biased, rather than reliable, information.Wahba,on the other hand, considered compliance with ISO 14000 or ISO 14001  as a proxy for good environmental performance; however, obtaining these certificates does not necessarily reflect the firms’ true environmental impact rather they serve only as an indication that they adhere to certain rules of eco-efficiency. Third, the conducting of studies at the macroeconomic scale involves a high level of complexity since while environmental impacts are barely comparable at the interregional level they are even less so at that of macroeconomic blocks. Moreover, macroeconomic databases are prone to miss regional ecological differences that might be significant in the evaluation of environmental impact and they also tend to aggregate firms from different sectors, thus resulting in heterogeneous samples.

The contribution of this study is to analyse the incidence of anthropogenic climate changes on economic performance by adopting a different approach to those taken by previous studies. Thus, the paper takes a microeconomic approach,drawing on a homogeneous sample of rice farms, and evaluating environmental performance by applying measures of actual environmental impacts,focusing not only on the externalities resulting from the firm’s immediate productive stage, but also those arising in the earlier productive stages of the inputs required by the farm. Additionally, we use a widely accepted methodology for measuring a firm’s environmental impact.Conventional farming is concerned above all with achieving short-term economic targets with the use of environmentally aggressive inputs across the whole agribusiness cycle to enhance economic performance.

The transfer of 0.1% – 0.5% of chloroplast traits via pollen in tobacco as well as parental inheritance of chloroplast DNA in other higher plants has been observed. In addition, Huang et al.  observed that transgenes can migrate from the chloroplast to the nuclear genome. Singh et al.described a strategy based on epigenetic inheritance and post-transcriptional gene silencing /RNA interference  that would allow allseeds from self-pollinated transgenic plants to be harvested and re-sown, without the need for specific treatments,while retaining all of the transgenes present in the parent while preventing outcrossing via either male or female gametophyte. The overall prospects of acceptance of transgenic crops and products will depend on positive public perception of this technology, especially as the agrobiotech industry complies with regulations, conducts rigorous research on biosafety and successfully completes field trials of these crops. Like any other newly developed technology,transgenic crop agrobiotechnology industry faces its own unique challenges and hurdles, especially relating to consumer concerns on health risks and environmental safety and barriers to world-wide trade.

Long term effects of GE foods must be rigorously studied but guidelines and regulations for field-testing and marketing of GM products likewise must be clearly defined to remove ambiguity and potential law suits.There are numerous technological challenges that must be overcome while attempting to introduce specific traits into a crop. Furthermore, the high cost  of developing and obtaining authorization for the commercialization of a transgenic event limits the development of transgenic crops only for selecting traits of wide interest. Agro-based companies like Monsanto, Dupont, Syngenta, DowAgro, and Bayer Crop Science have daunting task of generating profit for share holders while they are also sensitive to the farming community and have a humanistic, consumer-oriented approach.On positive note, numerous successes have been documented especially with regard to agronomic traits like herbicide resistance, pest resistance and drought tolerance. The high adoption rate of genetically engineered crops and controlled field trials and research in many developing countries and some EU countries are optimistic developments. The need to feed a growing world population, enhancing ability of crops to withstand climate change, and public preference for plant based industrial and pharmaceutical products should drive further research in GM plants and their production worldwide.

Successful commercialization and marketing of transgenic crops and products would require mutual understanding and implementation of international standards and trade policies among nations. In every part of the world, farmers engage in crop production with the aim of providing food, income, raw materials and foreign exchange among others for the citizens. Crop production is the act of cultivating the soil in order to provide food and other materials for man and industrial uses. Crops grown require soil nutrients and water in addition to sunlight to derive the photosynthetic process so as to produce edible products for man’s use. Crop production is climate sensitive with outdoor production activities that depend largely on particular levels of weather conditions. This means that crop production is one of the most sensitive agricultural sectors to climate change. Climate change is the significant and lasting variation in the statistical properties of the average weather condition when considered over long periods of time, regardless of cause . Climate change refers to the variation in the average weather condition attributed directly or indirectly to natural events and human activities which alter the composition of the atmosphere over a period of time. Climate change affects crop production in a number of ways, for example, it leads to variation in the rainfall pattern, altering soil composition and increasing pests and disease migration.

Though some crops might respond favorably to increased atmospheric weather conditions, growing more vigorously and using water more efficiently, higher temperature and change in rainfall patterns often alter areas where crops grow best and affect the makeup of natural plant communities. Weather-related events add further complexity to the science of crop farming,resulting to shortage of food supply and consequently leading to frequent rising commodity prices . There is need for farmers to seek for alternative means of enhancing their productivity through certain adaptation strategies.Adaptation is the adjustment in natural or human systems in response to actual or expected climate stimuli or their effects. In crop production, certain agricultural ICT tools and gadgets  have been developed for precision farming despite climate change challenges.Precision farming refers to information and technology-based agricultural management system to improve crop production efficiency by adjusting farming inputs to specific conditions within each area on a field.

Unfortunately, irrigation water is a costly input to rice farming, which accounts for 28% of the total cost of rice production. It has been estimated that approximately 22 million hectares of irrigated dry-season rice may suffer from “economic water scarcity” in Asia by 2025. Furthermore, rice farming may become increasingly threatened due to climate change and extreme natural disasters in terms of increasing temperatures and uncertainty of precipitation, drought, floods and salinity .Irrigated rice farming is an integral part of rice production system in Bangladesh,which contributes greatly towards total annual rice production and food security. However, our rice cultivation especially in dry rabi season requires large amount of irrigation water, which is of great environmental concern due to energycris is and methane  emission from rice field to the atmosphere, which acts as a potential greenhouse gas with 25 times global warming potential than carbondioxide.Boro rice cultivation is mostly dependent on irrigation water supply and the a man rice cultivation is partly irrigation water dependent.

As groundwater is the main source of irrigation in Boro rice field in northwestern Bangladesh, higher abstraction rate of groundwater may cause negative impacts on groundwater resources in the region.It has already been predicted that Bangladesh is going to face severe water crisis during dry season within the next couple of years. In this regard, alternate wetting and drying  of paddy field, developed by International Rice Research Institute, could save a significant volume of irrigation water 15% -30%  for rice production, mitigate CH4 emission and sustain rice productivity.The fertility of crop field in Bangladesh has been declining day by day due to continuous cropping and mining of nutrients, and indiscriminate use of chemical fertilizers. In this regard, biochar, mainly the carbon enriched materials with minute amount of plant nutrients obtained from organic matter under high pyrolysis temperature and oxygen limited condition ,could be the best organic manures to rejuvenate degraded soils. Biochar is an anaerobic pyrolysis product derived from organic material, resistant to easy degradation and capable of restoring soil carbon for a longer period of time by reducing greenhouse emission from soil to the atmosphere.

Moreover, the use of biochar will cut down the amount of chemical fertilizers for rice cultivation and GHGs emissions may be suppressed by modifying the paddy ecosystem. It has already reported that combined application of rice husk biochar and FYM with reduced chemical fertilizer under less water inputs was found effective to sustain wheat crop yield in the highly vulnerable dry tropical agro-ecosystem of India.Furthermore, Singh et al. reported that compatible agricultural practices based on specific agroeco system could be effective for climate change adaptations. Therefore, this study was undertaken to determine the suitable combination of biochar and chemical fertilizer  for sustaining rice productivity, minimizing yield scaled methane emissions and improving paddy ecosystem through water savings AWDI system. Soil redox status also improved in the biochar amended field plots, probably due to the cumulative effects of free iron oxides  in the rice rhizosphere which enhanced electron activity in soil and acted as electron acceptor, thereby enhanced soil porosity . At the end of the experiment maximum increment in soil porosity, soil pH, SOC, SO4-S and free iron oxides were found in biochar amended  field plots under conventional and AWDI systems.

In addition, higher concentrations of free iron oxides in soil could be from the total iron content in soil, where biochar amendment might have contributed as an additional source. In this study, the seasonal CH4 emission trends were found significantly high in dry boro season compared to wet a man season, which may be due to the variation in yield potential of the rice cultivars, irrigation water supply and consumption,meteorological and rice rhizosphere environmental variations within the seasons. CH4 flux was higher during reproductive stage of rice plant in all treatments,which may be due to higher availability of labile organic C from the decomposition of soil organic materials , higher diffusion rate ofCH4 gas through rice root and shoot aerenchyma from rice rhizosphere zone being supported by Kludge et al.  and Hiya et al. .

The sharp fall inCH4 emission rates at grain maturation stage in all the treatment combinations might be due to the aging of rice plant, leaf senescence, lack of available water and labile organic C as supported by Cai et al. .In this study grain yield was significantly influenced by biochar amend mentsand irrigation practices. The findings confirmed that biochar amendments 15 -20 t/ha with NPKS fertilizers maximized rice yield under AWDI method. In the dry boro season, rice yield was increased by19.6%, 13.6% and 6.5% with biochar amendments at 15 t/ha, 20 t/ha and 30 t/ha respectively, under conventional irrigation; whereas the corresponding yield increments were 19.0%, 14.2% and 6.9% respectively, under AWDI method.

They also indicated what steps they already had taken or would take under the “problem” situations.Socio-economic and agricultural survey were conducted during 2011-2012, over hundred households were included, the community typically include a large proportion of small holder farmers with poorly equipped , land scare household with low education and economic status with . Household socio-economic survey was conducted to estimate the contribution of different components to the income and the level of diversification both in the components of agriculture. Many of the action mentioned to improve water use efficiency, water scarcity being one of the reasons for the pronounced vulnerability of the Ethiopian agricultural production system, there being extremely low level of water resources management, either in the form of poor watershed management or investment in water infrastructure. This is more true in the Highlands of Ethiopia, the site of this study, home to the majority of Ethiopians dominated by small farm traditional agriculture.

The impacts of change of rain fall regimes were given more importance by the community in group discussions; they think this has been directly affecting local vegetation especially tree growth and reproduction as reflected in reporting impacts like “tree cover with no‘spongy’ soil underneath”, “seeds rarely found in the soil to naturally germinate”, “rain water runoff, erodes soil,remove tree seeds” “fewer seedlings in and around forest” and “no natural regeneration of trees”. Field observation and discussions indicated that in the past there was wide natural regeneration in and around forests and also people used to collect seedlings from the forests/forest edges for planting in their homes and crop fields, a practice no longer possible they reported because of scarcity of seedlings.Thus, both in nature and in homestead agroforestry tree propagation/regeneration likely to be affected by the climate change impacts, a number of studies also mentioned.It was evident that at the local level, the poor and impoverished rural community operate in the isolated, distant villages  with no direct road connection from the village to the Highway  and the villagers have to walk long distances to market their products.

Yet, the two approaches adopted in the study—formal questionnaire survey and informal group discussion—both demonstrated the villagers’ high level of awareness about climate change, its impacts and necessity for adaptation. Another recent report  also identified about 71% of the rural respondents in Ethiopia agreeing that there have been changes in the climate over the 20 – 30 years, in the amount of rainfall during the main season, delay in the timing, a reduction in the volume of rainfall insufficient for cropping.Livelihood, on the whole, depending on agriculture in the study area which is characterized by mixed farming,cereal production, vegetable/horticulture farming, livestock keeping and trees/shrubs growing being the main components , climate impacts are seen as a major factor by the farmers. Both field and homestead cropping being common, barley, wheat and teff were the main food crops in the past, but now niger seed, linseed, chickpea and field beans and vegetables are also introduced, all these were used both for food and cash earnings . All these field and home gardens  are rain-fed, traditional irrigation is practiced in very limited area about one fourth of the fields only for limited period of the year when water is available.

Home garden crops such as enset or false banana, potato, carrot, beet root, cabbage, garlic , shallot, onion, sweet potato and sugar cane  are managed by the women,now have a high contribution to the household income . Another important source is domestic animals having a crucial role in the livelihoods of the community providing power for traction and transportation, food,fertilization  and cash earning from both the products or live animal sale, though the poor farm households having few and only less valuable sheep and poultry. Also, woody trees and shrubs were reported as important sources of community livelihoods, getting economic and ecological benefits.Common trees being Eucalyptus spp., Justricia schimperiana, Myrica salcifolia, Premna schimperi, Cuperssus lustanica Cuperssuslustanica, Carisa edulis, Juniperus procera, Maesa lanceolat, Dovyalis abyssinica and Celtis Africana.

Thesmall farmers were found to intensify homestead and agroforestry systems to cope with the negative impacts of climate change at the village levels.As indicated in , petty trade,preparations and sales of local alcoholic drinks has been indicated to generated additional income to the community members under economic stress.Handicraft activities such as weaving , pottery  and local leather works, traditional articles made by women from selected grass species also contribute to homestead income . The farmers here have adopted different strategies to cope up with the consequences of climate change, the diverse components in their current farming system indicated this. They diversifying crops, barley, wheat and teff being the main cops, while maize and sorghum in patches and in home gardens; enset  and other shrubs, pulses , oil crops  are now taking more areas in the cropping combinations.

The purpose of classification of farming systems is to develop strategies and interventions relevant to the various systems which may vary in the types and degrees of severity of constraints, resource bases and enterprise patterns. Blanket recommendations of technologies and improved management practices could be one of the reasons for low adoption of interventions by agricultural systems which are highly diverse in agro-ecological and socio-economic conditions.Dairy farming systems in Ethiopia have been extensively characterized. Since dairy cattle genetic improvement strategies in Ethiopia target the peri-urban/urban system and the major milk sheds for introduction of exotic crossbred dairy cattle, the major distinguishing characteristics of the three highland systems is the herd genetic structure, the urban and peri-urban systems are characterized as cross bred-based systems keeping high grade exotic crossbred cows whereas the rural or traditional system is a local cattle-based system.

The studies cited above have however focused on the systems in and around the big cities and the major milk sheds. On the other hand, studies on regional towns have indicated that the crossbred herd composition in the urban/peri-urban system is less than reported in the above cited studies. Despite the extensive characterization of dairy farming systems, a comprehensive characterization of dairy systems in the highlands across the value chain supported with valid statistical analyses is not available in the literature.Secondly, the topology of farms within systems and the underlying determinants for within-system variation/diversity in herd genetic composition are not known to confirm if farms within systems could be considered as a uniform unit to target development interventions. In this study, we analyzed farms sampled form of two states in the wet highlands of Ethiopia to validate the classification of the smallholder dairy farming systems, establish the genetic structure of the three systems and identify within-system determinants of variations in herdgenetic structure based on a series of statistical analyses taking the small holder system in Ethiopia as a case study.

Questionnaire survey on herd genetic composition, herd size, production resources,and household characteristics based on farmers’ recall were collected from February to September 2015 using structured questionnaires. The data from West Shoa and West Gojam zones were analyzed separately to serve as are plication of the study. The genotypes of animals were classified as local, low grade, medium grade and high grade crossbreds based on the exotic blood level of the animals. Low grades were defined as those having about 25% exotic blood resulting from first cross cows backcrossed to local breed sire, medium grade crosses were first crosses with 50% exotic blood resulting from crossing of local cows and exotic bulls , and high grades were animals with about 75% or above exotic blood resulting from first cross cows crossed with pure exotic sire commonly through AI. The level of exotic blood level for cows supplied by government ranches and research institutes was established from the cow certificate provided by the institute. For animals that were born on the farm, exotic blood levels were estimated from the dam and sire breed type as recalled by the owner and from records of AI service providers.Discriminant function analysis was used to reclassify the 180 farms in each zone into their original rural, peri-urban and urban categories.

The model was composed of discriminant functions based on linear combinations of four predictor variables which represented the genetic compositions of herds. The predictor variables were local, low grade, medium grade and high grade crossbred animals in the herds. The variables that provided the best discrimination between the groups were selected based on their statistical significance. The classifications were cross-validated applying leave-one-out analysis where each farm was classified by the functions derived from all farms other than the farm to be reclassified. Multinomial logistic regressions were conducted to estimate the probability of keeping the various genotypes across the three farming systems. Factors that would determine adoption of the various genotypes by farmers in the three farming systems were identified through generalized linear regression analysis fitting Poisson distribution with log transformation of the number of animals as a dependent variable. All analyses were conducted using SPPS version 20 .

Using discriminant function analyses based on herd genetic structures as predictor variables, 180 farms in each of West Shoa and West Gojam zones were reclassified into rural, peri-urban and urban systems . The predictor variables that contributed significantly to the reclassification were number of local, low grade,medium grade and high grade crossbred animals in the herds in West Shoa,and number of local and high grade crossbred animals in West Gojam. In West Shoa, the classification function coefficients for number of local animals were marginally higher for the rural and peri-urban system than for the urban system, the coefficients for the number of low grade crossbreds was higher for the rural system than for the peri-urban and urban systems, whereas the coefficients for the high grades for the rural system were lower than for the peri-urban and urban systems.

Many therapeutic proteins or N glycoproteins synthesised in plants differ in their glycosylation patterns from those derived from the mammalian systems.This may also induce increased allergenicity or reduced immunogenicity. The glycosylation pathways in plants can be altered for humanising the plant-derived vaccines or therapeutic proteins. Environmental issues of plant vaccines include gene transfer and exposure to antigens or selectable marker proteins, while risks to human health include oraltolerance, allergenicity, inconsistent dosage, worker exposure and unintended exposure to antigens or selectable marker proteins in the food chain. These risks are controllable through appropriate regulatory measures at all stages of production and distribution of a potential plant-made vaccine . The potential and prospects of plant made pharmaceuticals is restricted by the potential of transgene spread from crops through outcross, challenges in transgene bio containment, unpredictable impact of epigenetic events on transgene expression etc.

Plant cell culture bioreactors or greenhouses and use of plant virus expression systems to produce vaccine proteins in large quantities can be thought of as safer alternatives. The infamous escape of transgene in case of Prodigene and Starlink corn are examples. ProdiGene produced a transgeniccorn that expressed a vaccine for preventing bacteria-induced diarrhoea in pigs,but in 2002, ProdiGene failed to eradicate plants that had seeded from their previous season’s transgenic corn crop which contaminated non-transgenic soybeans.In 2003,the Animal and Plant Health Inspection Service of theUS Department of Agriculture made it mandatory for engineered plants producing pharmaceuticals to be grown under permit. Inefficient transgenebio containment is a serious hurdle to commercialisation of molecular pharmingusing plants. Regulatory hurdles remain a barrier to molecular farming, further increasing the cost and time, which otherwise are major advantages of plant-made vaccines.

Purification, quality controls for vaccine approval are major cost factors in vaccine production . Containment of the recombinant material is a concern which needs to be carefully monitored, to prevent these from entering the food chain and environment. The recombinant plant-based vaccines produced in transgenic plants must undergo a tight regulatory process before commercialisation.The paradigm of plant-made vaccines has evolved from vaccines consumed by world’s poorest populations through fresh producederived from their local farm, to eating engineered fruit or vegetable sprescribed by a health care worker, to a plant product derived from batch processed,freeze-dried plant tissues prescribed by a health care worker to current aradigm that PMVs are not food materials that need to meet still-evolving regulations of national regulatory authorities for drug administration and Department of Agriculture . Plants producing pharmaceuticals are regulated by USDA and the regulatory framework is developed by the FDA and Centre for Veterinary Medicine. The antigen present in edible vaccines is considered as a chemical, that does not comply with FDA rules concerning nutritional additives, but is recognized as non-GRAS.

These vaccines, under the category of food, would be included as a genetically modified food and thus are not considered a high health risk. Due to this ambiguity, a legal void currently exists with respect to regulations for standardizing edible vaccine commercialization. It is not yet clear what part of the vaccine discharges the antigen itself, the transgenic, modified fruits or the transgenic seeds . In the presence of this legal uncertainty, every country is expected to evaluate whether the entrance of edible vaccines is permitted. In 2005, the World Health Organization delivered a report on the implementation of good agricultural practices for the development of biopharmaceuticals. This report includes detailed information about methods of quality control for medicinal plants, testing to assess identity and purity, and recommended materials for plants in biopharmaceuticals. Bio-farming or molecular farming is attractive because of its flexibility, scalability,low manufacturing cost, no toxicity or pathogenic contamination, but many projects are at various developmental stages and not many are yet available to the pharmaceutical industry.

Optimization of lab protocols for up-scaling the production of therapeutics at commercial level is important for clinical use.Plant metabolic engineering is a highly significant technology for production of high-value pharmaceutical compounds. Fusion proteins for multicomponent vaccines against multiple diseases are a potential tool to incorporate into immunization programmes. Unlike genetically engineered microbial systems such as viruses, which pose more risks to the environment and humans, and have more chances of escape, difficulty in controlling and monitoring such escapes or unintended presence, plants are immobile. Control, containment and monitoring of genetically engineered plants are easier and containment can be achieved by regulating pollen transmission.

The challenges to develop and produce vaccines and therapeutics are immense, due to the ever-increasing or rapidly evolving pathogens, resulting in greater demand than supply. Rapid development and large-scale production of vaccines is the need-of-the-hour in case of an unexpected global calamity of a pandemic of massive scale. Plants offer a safe alternative for low-cost as well as large-scale production system for the vaccines, especially in developing countries. The review describes the strategies, advantages, challenges and prospects in the production of plant-based vaccines. A vaccine provides immunity against a disease. Vaccines used for immunization against diseases can be categorised into live attenuated vaccines, inactivated vaccines,subunit, recombinant or conjugated vaccines, toxoid-based vaccines, viral vector-based vaccines and nucleic acids-based vaccines.Live attenuated vaccine uses weakened or attenuated form of a pathogen, that causes a disease. They provide strong long-term immune response as they are similar to natural infection.

Attenuated vaccine may have small amount of the live virus which may be risky for people with weak immune system. Also, they require cold storage facilities. Live attenuated vaccines are used against smallpox,chickenpox, Measles, Mumps and Rubella etc. .Inactivated vaccines use killed or inactive pathogen and require booster doses of vaccine for immunity . Flu, pertussis, polio, rabies vaccines etc. are inactivated vaccines.Subunit, recombinant, polysaccharide and conjugate vaccines use part of the pathogen such as protein, capsid , sugar moiety etc. Subunitvaccines comprise of purified antigen derived from the pathogen, while conjugate vaccines, consist of a polysaccharide component of the pathogen that is poorly immunogenic, so that it is chemically linked to a protein. Recombinant subunit vaccines are safer since they do not have a pathogen and can also be scaled up. Since subunit vaccines consist of small fractions of the pathogen, immunogenicityis greatly decreased with respect to those derived from whole cells,generating the need for co-administering adjuvants to attain immune-protection.

They can be used in patients with weak immune systems and require booster doses to maintain immunity. These vaccines are used against Hepatitis B,Whooping cough, Human Papilloma Virus etc.Diphtheria and tetanus vaccines are toxoid vaccines .Viral vector-based vaccines such as Adenovirus or measles virus vectors are highly versatile platforms for vaccine development. Viral vector-based vaccines can be used for different viruses, delivered without additional adjuvants and can be administered as intramuscular, intranasal, intradermal and oral vaccination.High yield production processes and means of up scaling have been established for these vaccines so that they can be used immediately in case of apandemic outbreak. But viral vectors are genetically modified organisms considered as potential risks to human health and environment and unsafe due to persistent replication of attenuated vaccines. Viral vectors can integrate into the host genome, or undergo recombination during production, leading to emergence of uncharacterised or novel pathogens.

These safety concerns might also delay clinical studies in case of a pandemic. Viral vector-based vaccines are highly complex and comparatively cost-intensive .Nucleic acid-based vaccines employ antigen-encoding plasmid DNA or RNA or messenger RNA or viral replicons. Due to the ease of antigen manipulation they are also versatile. Vaccine can be developed against various pathogens such as virus, bacteria or parasite and administered as intramuscular or intradermal injections. A eukaryotic expression cassette carrying the antigen is inserted into a bacterial plasmid for propagation in E. coli . Minimal DNA constructs devoid of a bacterial backbone, such as the semi-synthetic minicircle DNA and the fully synthetic Doggy boneTM, have been developed to avoid safety issues related with selectable marker. DNA vector vaccine provides relatively low immune-genicity, since DNA vaccines must cross both plasma and nuclear membranes for protein expression, unlike the RNA vaccines which upon crossing plasmamembrane are translated. Encapsulation of DNA vaccines in lipid nanoparticles,adsorption to polymers and use of molecular adjuvants like cytokines can enhance the uptake of DNA vaccines and enhance the immune response. DNA vaccines have long-term persistence, however, potential risk of genomic integration of exogenous DNA into the host genome or chromosomes may result inmutagenes is and oncogenesis or new diseases. Molecular adjuvants like cytokines may also have undesirable, side-effects such as inflammation or autoimmunity.DNA vector-based antigen expression is the first effective vaccine against Ebola virus, Zika virus etc. and used against human pathogens such as HIV, influenza virus, malaria, hepatitis B virus, respiratory syncytial and herpes simplex virus .

The arrival of most of the pests, such as army worms, was detected in the minor season when there were prolonged dry spells.The pests had the capacity to devour large tracks of maize, increasing the production cost of the poor-resourced farmer. Apart from army worm infestation,diseases like maize streak and stem borer were also causing distress to the farmers.The presence of these pests and diseases were facilitated by changing climate in the Municipality.The respondents were asked what they did when their crop failed; 23%of them reported that they sold other farm produce, 15% of the respondents engaged in trading activities, whereas 12.3% traded in farm animals with about20.5% of farmers doing virtually nothing. Six percent of the respondents lived on borrowing money from friends and relatives. Precipitation was low in the early 1960s but rose steadily in the mid-1960s,falling suddenly in the 1970s. Rainfall, however, progressively rose and somewhat stabilised in the mid-1970s and declined again in the early 1980s.

There was no clear pattern from 1988 to 2015. It was also obvious that from 1988 to2015, the rainfall amount hardly crossed 1000 mm unlike the period between1960-1982. This confirms the farmers’ perception that the current rainfall pattern is rather irregular and unpredictable.The averages of 1960-1982 were higher than that of the present, 1988-2014. From the months of January to March, the mean of 1960-82 was greater than that of 1988-2014. The farmers were right that lately, the amount of rainfall in March had drastically fallen as the amount from 1960-1982 was well over 100 mm , whereas the average amount for theperiod between 1988 and 2014 had reduced to 71.0 mm, which most probably accounted for the reason why majority of the farmers sowed in April .Between 1988 and 2014 rainfall averages had appreciated from April to June,with a deficit in July, rising again in August. Currently, the amount of rainfall in November has decreased to the detriment of farmers. This means that presently,crops do not receive much rainfall as compared to 30 years ago. It can also be inferred from Table 2 & Table 2 that presently, August is getting wetter and the major and minor seasons are progressively merging. It is also clear that the first and the last quarters of the year are getting drier over the last couple of decades with the last five years being the worst.The future seems to be rather bleak looking at the trend in 1960-1982 with almost no rains in November and December.

The average total amount of the period 2010-2014 showed a reduction of 22% over the past five years with a decline between 1960-82 and 1988-2014 of6%. The month of March which was meant for planting of crops now obtained64.5 mm of rainfall against 114.7 mm in the past buttering farmers assertion that climate had changed. On rainfall regularity, the pattern of precipitation in the Municipality is chararcterised by uncertainty. Based on the above tables the amount of rainfall in the month of August increased but figures from 2015 deviated from the trend. The precipitation received in the August,2015 farming season was 0.00 mm. Table 2 also shows a reduction in rainfall amounts between June and August. This phenomenon might have had a negative effect on maize production in 2015, resulting in the lowest yields of maize recorded for the Municipality in the last six years. A report by indicated that even though other contributing factors exist, rising temperature and irregularity in precipitation are the major causes of the continuous reduction in maize yields. Annual rainfall for Nkoranza South Municipality since the 2008/9 farming season for the month of March had never risen above100 mm but rose to 11 mm in 2015 which confirms that the nature of rains in the transitional zone is irregular. According to , declines in total precipitation and increasing irregular rainfall patterns make farming more hazardous,increasing the likelihood of crop failures and reducing agricultural production.

Of these, 78% indicated that the nature of the change was erratic.The majority of the respondents established that the severity of this episode was devastating over the past 5 years. This had therefore made their farming operations riskier as there was no irrigation system in the Municipality, bringing farming activities to a near halt whenever the rain failed .About 65.5% of the farmers admitted that unguided activities of unscrupulouschainsaw operators had led to the cutting down of trees which might have resulted in reduction in rains. On the other hand, 25.5% attributed the changes in precipitation trend to nature itself and 0.5% of the respondents believed that the changes had come due to excessive emission of GHGs into the atmosphere.Another 5% of the farmers also placed the blame on bushfires whereas 3.2% indicated that they did not know what had caused this change.When they were further probed about what could be done to reverse the situation of the erratic rainfall, 64.1% responded that there should be afforestation to replace the felled trees. Others had the view that only God could intervene to restore the situation whilst some farmers called for bush fire control.

Of the several crop models, the FAO CROPWAT and SMACS models can easily be adopted with very little field data demand. The latter has also been tested for the same study area for observed climatology of 42 years covering the period 1961-2002, under no-climate change conditions. FAO’s CROPWAT is a monthly crop model which considers daily rainfalls applied on selected days of each decade. SMACS is a daily-moisture accounting model adaptable for different crops, and externally coupled with daily rainfall and temperature generation model. Another advantage of the SMACS model is that it easily enables/allows external coupling with GCM outputs with possible disaggregation to daily values using weather generators.Beyond impact assessment, the SMACS model can be used as a decision support system as it can also be usedto calculate water balances such as actual crop ET, excess surface runoff and actual soil moisture besides yield and crop stress indicators. It is therefore suitable to evaluate and investigate the potential of and promote rainwater harvesting and conservation agriculture practices as potential adaptation measures.

The water requirement of the crop at a given time of the growing season is calculated by multiplying the reference evapotranspiration with a crop coefficient, whose values are published by FAO . SMACS model is considered due to easy adaptability to simulate soil moisture balances, crop water demand and stress for current climatology as well as post climate change conditions.In the SMACS model, all precipitation in excess of surface runoff to potential transpiration is used as the environmental indicator of water stress and yield potential -. In the crop models considered in the study, water stress is assumed in the crops to affect growth by limiting photosynthesis in direct proportion to the ratio of actual to potential transpiration. The common approach for estimating crop yield reduction is based on FAO experience, which addressed the relationship between crop yield and water use by proposing a simple equation where relative yield reduction is linearly related to the corresponding relative reduction in evapotranspiration .Future climate changes, as well as differences in climates from one location to another, may involve changes in climatic variability as well as changes in the means. In this study, a synthetic weather generator is used to systematically change the within-year variability of temperature and precipitation, without altering long-term mean values.

For precipitation, both the magnitude and the qualitative nature of the variability can get manipulated. The synthetic daily weather series serve as input to the three crop simulation models. Due to its transboundary linkage and since it exhibits similar agro-ecological characteristics extending and covering Southern Zambia, eastern Namibia, western Zimbabwe and north-eastern Botswana, the site was considered as an ideal site for assessing the climate change impacts of rain fed farming systems. Furthermore, the study site is a vast agricultural area where rain fed agriculture is currently practiced.The area is characterized by the presence of heavy clay soils. It is understood that during the rainy season they are liable to become sticky, waterlogged and poorly aerated, and they become hard during dry periods. They are reasonably fertile and are capable of retaining both water and nutrients . Successful cultivation and good management in some areas have shown that these soils are able to make a significant contribution to food production.Because of low drainage, harvesting rainwater excesses can be practiced in such soil conditions.The climate of the project area, like most of the north and south-eastern Botswana, is sub-tropical and semi-arid. The climate records at Kasane and Pandamatenga compiled by the Department of Metrological Services have been available for the study. The monthly air temperature variation in the project area computed from 1971-2000 recorded data indicates a mean daily minimum and maximum temperature of 15˚C to29˚C, respectively.

The highest temperatures are prevalent during November to March of the year while June and July experience the lowest temperatures.Figure 2 shows the annual temperature variations and general trend in the daily maximum and minimum temperature data of Francistown, a nearby climatic station for the period 1971 to 2000. Wind direction is normally easterly, north-easterly and south-easterly. The incidence of higher winds is greater around September,October and November with average speeds of above 180km/day.Rainfall is characterized by short periods of heavy rain, which cause flush flooding. The men annual rainfall in the study area is generally about 550 mm. The study attempted to establish and understand the degree of susceptibility of crop to failures in terms of soil moisture availability to meet the evapo-transpirative demands of crops studied. Using the SMACS model, the following indices, namely risk, resilience and reliability were used to investigate the available moisture failure rates in rain fed conditions, where rainfed agriculture is practiced in the study site. In this study, daily simulations from climatic data of 1971-2000 were made for the study area, considering commonly grown crops: maize,sunflower,and sorghum.

Numerous overhead costs like the construction of thegreenhouse, a viable model or tray systems or buckets to name a few. These maybe a disadvantage; however, the literature shows that the larger-scale hydroponicsystems tend to be more cost-effective than small-scale land-based farms. Thecost analysis of using the hydroponic grower as compared to traditional farmingis shown in Table 1. As it is presented, the payback period starts in the thirdyear. On the other hand, the traditional method allows the payback period withinone year. The harvest under a traditional method may be affected by weathercondition and other causes extraneous to the traditional farmer. Table 1 showsthe cost analysis of vertical farming using hydroponics and its comparison totraditional land-based farms.

As presented in Table 1, on the second year, the total remaining balance inVertical Hydroponic Farming method will be $59954.94. The remainingloan balance is $48,000 which could be paid in full. And the remaining balancewill be $11954.94 less the total operational expenditure of $8010.47. On the thirdyear, the initial investment will be $3944.47. Therefore, the Return On Investment will be in the second year. Moreover, the remaining area of land could be utilized for planting other crops. For the traditional farmingmethod, although the loan was paid immediately, it is shown that the remainingbalance on the second cropping is smaller than that of the VHF method. However,in the traditional method, third cropping is not possible because the landmust recoup from the exhaustion of nutrients due to the two cropping seasonsand the weather condition during the third cropping is volatile and inappropriatefor onion production. More so, using the traditional method, the entire10,000 m2 farmland area was used while in VHF system, the remaining lot space could be used for other agricultural and live stocks production. The VHF is alsofree from unfavorable weather condition as the onion grows under an artificialenvironment and controlled physical surroundings.

In many studies, the plant’s growth rate is higher in Vertical farming using hydroponicstechnology. Using the system will provide the farmer control of thefarm allowing more significant results. With hydroponics, the farmer will have full control over the farm together with more optimal results. The growth ofonion is shown in Tables 2-4 below. Hydroponic onion did as well if not evenbetter than the plants grown in soil. Notwithstanding the higher cost of initialcapital, increase crop yields would compensate the investment . The systemcan also serve as an alternative to land-based farming in areas where the landsoil is poor in quality. When the technology is applied correctly, the growth ofthe plants is observable hence could provide earlier harvest resulting in threecropping seasons per year. Table 2 shows the data yielded by the experiments.The Table 2 presents the growth of onion planted in a vertical grower applyingthe hydroponic system of providing nutrients to the onion. It is observedthat there is a 2.5 cm average bulb diameter yielded within a 30 day period. Fromthe 2 cm initial bulb development, it grew to 3.1 on the 30th day of the experiment.On the next scheduled experiment in May 2017, the initial bulb diameter onthe first day developed to 4.1 cm on the 30th experimental day.

This goes toshow that compared to the first experimental phase the bulb development ofonion in the second experiment is relatively bigger. The result is attributed toextraneous variables which the researchers were not able to control in the firstphase of the experiment. On the average, the onion bulb development in thesecond experiment yielded an average growth of 3 cm in a 30-day period.The results of the final and last phase of the experiment are shown in Table 4.As it is depicted in the table. There was a 0.02 cm increased in the developmentof bulb diameter compared to Table 3 Phase 2 experiment yielding only a 4.1 cmgrowth of onion bulb smaller than the result of July 2017 3rd and last phase ofthe experiment.The three phases of laboratory experiments scheduled in three different crop seasons clearly showed that the technology is adaptable to onion growing. Theresults of the experiments are similar to that found out by the researchers of theNational Aeronautics and Space Administration.The present study affirmsthe result of the NASA researches where onion, like any other vegetables,can be grown using artificial simulated environment.The Figure 5 shows theactual observation of the study.The Figure 5 showed the hydroponic technology as applied by the scientistshaving the vision to bring the technology in outer space where there is no landor soil where plant or vegetables could be transplanted to sustain their food.The NASA researchers are checking hydroponic onions with Bibb lettuceto his left and radishes to the right.