Transgenic approaches for improving water stress tolerance and leaf retention were also considered

Genetic modifications through the use of the modern recombinant DNA technology may play an important role in improvement of the crop only when it complements and integrates with other fields of science and not done in isolation . Moreover, to be cost-effective, the technology outputs must be tested and evaluated in whole-plant and within relevant cropping systems under prevailing environments as well as under predicted climatic changes in the 21st century . Connor et al., in their recently revised Crop Ecology text book , have rightly commented on the current research efforts targeted towards genetically transferring the quite complex C4 photosynthetic syndrome to C3 rice, where significant financial support was recently devoted to, by saying: “What a pity that cassava does not share the world-food limelight with rice. 

This species has the most, and best studied, intermediate photosynthetic types, and beneficial growth and yield responses have been demonstrated in them . The pathway to success ought to be shorter for this crop. It would be exciting to see progress in the search for this current holy grail of biotechnology during the lifetime of this book.” Quote. Research institutions and donors agencies concerned with agricultural research and development must be aware of the high potential of cassava as food, feed, and industrial crop and its role in the face of global climate change. The author wishes to express his gratitude to Colombian farmers for their hospitality during conducting some of this research. Without the collaboration of the many former field laborers, secretaries, research associates, students and colleagues, who are now dispersed across countries, the achievements highlighted here would have never been obtained. The invaluable courtesy copies of books documenting important research on crop ecology by David Connor, Robert Loomis and Kenneth Cassman, and on climate change by Mary Beth Kirkham, and Cynthia Rosenzweig, article reprints from Andy Jarvis, Julian Ramirez-Villegas and David Rosenthal were appreciated.

I am grateful for the waiving of the required pagecharges by the Editors of OJSS.Thanks to Farah El-Sharkawy Navarro for the editorial and the WWWnet search assistance. With nearly 60% of its population under the age of 25 years, Africa is the “youngest” continent on earth . Currently hosting a total of 1.37 billion people , corresponding to almost a double of Europe’s 750 million, the continent is expected to reach the size of 2.5 billion inhabitants by 2050 and of approximately 4 billion by 2100 . By then, one person in every three worldwide will be from the African continent. This exponential growth is expected to be accompanied by an equally significant increase in the continent’s need in animal source foods. Indeed, Africa’s demand for meat, milk and eggs will almost quadruple by 2050 , with annual growth rates of consumption estimated at 2.3% for milk and 2.8% for meat . Currently, however, not only Africa is overall a net food importer , but it is also the most food insecure region in the world, the only one in which the absolute number of undernourished people has increased in the past 30 years , and where that of stunted children under five is still rising . Presently, nearly 60% of Africans are moderately or severely food insecure, with more than 90% of them residing in sub-Saharan Africa . At thesame time, overweight rates are also increasing , highlighting the continent’s need for nutritious foods. Yet, Africa harbours 60% of the world’s uncultivated arable land , with one-quarter of the world’s cultivable land being in sub-Saharan Africa but only producing 10% of the global agricultural output .

Therefore, the continent’s rising demand for animal protein could be potentially met, at least partly, through enhanced local agricultural production, made possible by improving the productivity of farming processes , as envisaged by the African Union’s Comprehensive Africa Agriculture Development Programme  and New Alliance for food security and nutrition . This agricultural transformation process may also include possible access by livestock keepers to wild areas hardly attended or inhabited thus far, to make room for livestock rearing and grazing . By creating new human–animal–environment interfaces, such an expansion may however bring health risks, as pathogens from wildlife could spill over onto domestic animals and people . Moreover, the ongoing climatic changes and global warming may also compound this scenario.

The heart rate is determined by the firing frequency of the sinus node

The data for the physiological/psychological evaluation was indicated by mean ± standard deviation.We asked the stimulation group open-ended questions about their image of soil scent after they had smelled the soil. All the subjects gave a reply except for one. Eight subjects imagined landscapes and experiences related to soil scent, and one subject had no image. Two participants replied as to whether they liked the soil scent or not .In this study, we compared subjects which were presented with the scent of soil and those which were not . Consequently, although the control group showed no physiological changes, the stimulation group showed a significant decrease in heart rate . This frequency is influenced by the dominant sympathetic nerve and vagus nerve, thus leading to either excitability or inhibitory.

For this reason, periodic activity of the brain stem and higher order cerebral cortex that synchronize with signals from arteries and veins and changes in blood pressure influence behavior, emotions, circadian rhythm, which increase through hyperactivity of sympathetic nerve functions, and decrease through hyperactivity of parasympathetic nerve functions . In this study, the heart rate of the stimulation group decreased, but there was no significant difference between HF that is a parasympathetic nerve index of heart rate fluctuation and LF/HF that is a sympathetic nerve index. Thus, we conclude that neither the parasympathetic nerves nor the sympathetic nerves function independently. In the open-ended questions about what kind of image subjects associated with the soil scent, some of the answers included “insect collecting” in the mountains, a forest, and horticultural therapy. The sense of smell enters the limbic system which is responsible for processing memory and creating emotion and reaches the hypothalamus that is also an autonomic nerve center.

Accordingly, the emotional response from an individual who is stimulated by a scent can cause physiological changes in brain waves and various autonomic nerve functions. The heart rate is adjusted by the autonomic nervous system or endocrine system, and can change according to the subject’s posture, and physical and mental activities . Therefore, for the heart rate that showed significant difference, we performed a Pearson’s correlation analysis among the degrees of changes at the points of Stim and Post 15 against Pre, and the degree of changes at the point of Post against Pre in VAS and POMS, and examined the psychological factors related to heart rate . As a result, the degree to which the heart rate decreased after smelling soil scent had a significant negative correlationwith the factors “feel relaxed” and “feel soothed” as indicated by the increase in the VAS scores. Therefore, in this study, we found that the healing effects and autobiographical memories induced from smelling the soil may lead to hyperactivity of parasympathetic nerve functions or suppression of sympathetic nerve functions which may influence the heart rate.Water and soil are important natural resources that play a prominent role in domestic activities and agricultural development in most African cities, the pressure on the use of these resources is constantly increasing due to the exponential increase of the population orchestrated by rural exodus. In this situation, the design of food stuff supply is modified in urban and peri-urban areas of Yaounde in Cameroon .

Vegetables are valued by the population; therefore vegetable farming is not only a source of food supply but also a source of employment in agricultural sector . This activity is mainly located in swampy lowlands, slopes, roadsides with heavy pressure on space . Vegetable farming reveals an interaction among the categories of actors, spaces types, crops species, the products obtained and the average incomes generated . It thus constitutes one of the main economic activities on which the population depends. This type of agriculture is demanding in terms of soil fertility management and water supply. There is a significant investment in crop techniques, fertilizers used, and pesticides treatments to meet the ever-increasing demand throughout the year. The increasing demand for vegetable produces leads to an intensification of their production aiming to high yields, which may negatively impact the preservation of water and soil resources . This study aimed at having a better knowledge of the characteristics of the vegetable farming in Yaounde, Cameroon.Steeper slopes occur locally whereas flatter tracts of land are found on small plateaus. The average annual rainfall among to 1600 mm and occurs in a bimodal configuration such that the first and second cropping seasons, separated by a 4-month dry season, last from mid-March to early July and from late August through mid-November respectively .