Rapid urban growth in sub-Saharan Africa challenges food supply of cities. As food and other organic matter are transported from production areas to consumption points, water, which has been used for their production, is transported virtually. This study aimed at determining the magnitude and sources of virtual water flows in food trade of two West African cities, in order to better assess food provisioning risks and water resource use and planning. To this end, flows of unprocessed food from local, regional, national and international sources were systematically recorded at all roads leading to Tamale, Ghana and Ouagadougou, Burkina Faso. The survey was conducted within two years covering the peak (November - December) and lean season (March - April), respectively, for six days in a row. Virtual water flows were computed by multiplying the flow quantities (t yr⁻¹) by their respective virtual water contents (m³ t⁻¹). Results showed that virtual water of all food commodities imported to Tamale and Ouagadougou were 514 and 2105 million m³ yr⁻¹ respectively, out of which 68% and 40% were re-exported to other regions of the country. The data also showed major seasonal variation in virtual water flows across the year. Reflecting their dominating role in local diets, cereals contributed most to the total virtual water inflows in both cities. Southern Ghana is the major net virtual water importer from Tamale through cereals, legumes, vegetables, and livestock. The Northern Region of Ghana, on the other hand, is a net exporter of virtual water in all food groups apart from fruits. In Ouagadougou, large flows of virtual water were imported in cereals, specifically rice from Asian countries, via Ivory Coast.

Nutrient imbalance and soil moisture stress are the major abiotic constraints limiting productivity of cool season food legumes. These constraints are more pronounced in the semi-arid tropics and sub-tropics which are the principal production zones of chickpea, lentil and faba bean. The legumes are generally grown on residual moisture as a mono crop and consequently face drought especially during the reproductive phase. In recent years, chickpea, lentil, peas and faba bean have been grown in some areas with an irrigated/assured water supply under intensive cropping to sustain cereal based systems. An increased water supply favourably influences productivity in dry environments. Faba bean, French beans and peas show a relatively better response to irrigation. The pod initiation stage is considered most critical with respect to moisture stress. Excessive moisture often has a negative effect on podding and seed yield. Eighty to ninety percent of the nitrogen requirements of leguminous crops is met from N2 fixation hence a dose of 15?25 kg N ha-1 has been recommended. However, in new cropping systems like rice-chickpea, higher doses of 30?40 kg N ha-1 are beneficial. Phosphorus deficiency is wide spread and good responses occur to 20 to 80 kg P2O5 ha-1, depending on the nutrient status of soil, cropping systems and moisture availability. Response to potassium application is localized. The use of 20?30 kg S ha-1 and some of the micronutrients such as Zn, B, Mo and Fe have improved productivity. Band placement of phosphatic fertilizers and use of bio-fertilizers has enhanced the efficiency of applied as well as native P. Foliar applications of some micronutrients have been effective in correcting deficiencies. Water use efficiency has been improved with some management practices such as changed sowing time, balanced nutrition, mulching and tillage | Masood Ali, R. Dahan, J. P. Mishra, N. P. Saxena, 'Towards the More Efficient Use of Water and Nutrients in Food Legume Cropping', Linking Research and Marketing Opportunities for Pulses in the 21st Century, vol. 34, pp.355-368, Springer Netherlands, 2014

Pandey et al., 'Adaptation of food legumes to water stress: use of line source sprinkler system', Paper presented at the IRRI Saturday Seminar, April 16, 1983. 38 p.

Legumes, which include a great variety of seeds, are distinguished by their protein content. Legume seeds produce defensive compounds against fungi and insect predators, and these compounds can be extracted or isolated for antimicrobial use. Isolation and identification of legume proteins and peptides have been extensively studied as part of the search for antifungal compounds. Researchers have recently started to pay attention to the antimicrobial activities of legume proteins, lectins, and peptides; however, few overviews regarding their antifungal activity are available, particularly concerning food applications.This review summarizes the main legume proteins and peptides with antifungal activity and their principal antifungal mechanisms of action. Further, potential food applications of legume water extracts and legume crude protein extracts with antifungal activity are discussed.Most studies have focused on isolating and identifying proteins and peptides with antifungal activity. Antifungal mechanism of action has been established for legume defensins. In contrast, legume water extracts and legume crude protein extracts have been subjected to less investigation; however, these preparations have been explored for food applications, particularly in bread, with interesting results. Despite their antifungal activity, practical applications of legume proteins and peptides have yet to be found. This is due to their low yields, high costs, and poor safety regulatory status. Therefore, further research on legume water extracts is necessary before food applications can be broadly developed.

Pandey, 'Drought adaptation of four food legumes. II. Influence of water stress on plant growth', In: Asian Farming Systems Network Selected Papers on Cropping Systems Research, 12 p. Los Banos, Laguna, Rice Farming Systems Program Staff, IRRI, 1984.

N P Saxena, . et al, 'Characterization of drought and adaptation of cool season food legumes to water-limiting environments', pp.661-677, 2012 | Non-irrigated (rainfed) agriculture is the major crop production system worldwide. It occupieslarge proportion of total land areas in Asia (88 %) and Africa (99 %). In some importantfood legume growing countries in South Asia, r

Pandey, 'Drought adaptation of four food legumes. II. Influence of water stress on plant water status, canopy temperature, and relations with seed yield', In: Asian Farming Systems NetworkSelected Papers on Cropping Systems Research, 13 p. Los Banos, Laguna, Rice Farming Systems Program Staff, IRRI, 1984.

Deep root penetration, which allows access to deep soil water and hydraulic lift, may help plants to overcome drought stress. The aim of this study was to evaluate the ability of sixteen food crop species to take up water from deep soil layers and the extent of hydraulic lift by the use of deuterated water. Plants were grown in pots consisting of two loose soil layers separated by a hardpan and a Vaseline layer. The lower (deep) layers were always kept wet (32%; ψ = –5 kPa), while soil moisture in the upper (topsoil) ones was adjusted to 25% (ψ = –7 kPa) and 12% (ψ = –120 kPa) in the well-watered and drought treatments, respectively. The deuterium labeling of the deep soil water provided evidence that wheat, Job’s tears, finger millet, soybean, barnyard millet, rice, and rye (in decreasing order of D2O increments) extracted more water from the deep layers under drought than well-watered in topsoil. These species showed significantly greater hydraulic lift under drought, except for soybean. Most of these species also showed increased root length density in deep soil layers and sustained high photosynthetic rates under drought. In contrast, pigeon pea, cowpea, common millet, pearl millet, foxtail millet, maize, barley, and oat did not show a significant increment in either deep-water uptake or hydraulic lift under drought. In summary, increased extraction of deep soil water under drought was closely related with the magnitude of hydraulic lift.

Legume waster water has been revealed to contain sufficent nutritional value as an industry by-product. In this study, physicochemical properties and protein profile of pea, chickpea and soybean soaking and cooking water were investigated. Among the three legumes isolates with their wastewater, all of the cooking wastewater exhibited the lowest content of free amino acid. In the yellow pea free amino acid assay, the soaking method contains the highest volume of Ser (6.00mg/g), His (6.01 mg/g), Phe (7.48 mg/g), Ile (4.12mg/g) Thr (4.27 mg/g) and Met (1.68mg/g). Chickpea soaking water has the highest volume of His (12.05mg/g) Phe (16.43mg/g), Ile (9.77mg/g), Thr (10.12mg/g) and Met (11.08mg/g). Pea cooking water Met to Lys is 0.8, which gave it the most elastic properties to form the sponge cake and more nutritional value. To identificate the emulsifying properties, oil-in-water emulsions containing 50% Canola oil were prepared using the legumes wastewater (pea, chickpea and soybeans). These emulsions were then stored at 4°C, and changes in particle size were monitored throughout storage. Chickpea cooking emulsions showed the smallest droplets distribution in the original emulsions. The mean emulsion droplet diameter (nm) evaluated differed significantly(p<0.05) for all centrifugated legume wastewater-based emulsions. Different types of legumes affected emulsifier stability because of different protein content. In conclusion, soybean soaking and cooking water have the best emulsifier stability both at room temperature and the refrigerator temperature, pea cooking water was investigated to form the hardest sponge cake because of its highest protein content.