Situated on the western edge of Africa's harsh Sahel region, Senegal faces a number of agricultural production constraints. Limited rainfall, poor soil fertility, and insufficient agronomic inputs all contribute to low yielding millet production systems. This study was initiated to assess the potential for intercropping either cowpea (Vigna unguiculata (L.) Walp.) or mungbean (Vigna radiata (L.) Wilczek) into traditional pearl millet (Pennisetum glaucum (L.) R. Br.) cropping systems. During the 2013 and 2014 growing seasons two varieties of cowpea (upright and viney), and one variety of mungbean (upright) were grown in monoculture and subsequently intercropped with millet to evaluate the potential for increasing millet and overall yields. Millet was also planted with a mulch (2 t/ha of neem leaves) to test the effectiveness of increased ground cover on millet yields. In addition to yield data, soil moisture and plant NDVI data were also collected. Millet grain yields increased when intercropped with either cowpea or mungbean compared to millet that was grown alone, with grain yield increases of up to 55%. Additionally, the combined grain yields (millet + bean) were up to 67% higher than the traditional monoculture millet. The addition of mulch was the most effective treatment and increased millet grain yields up to 70%. Soil moisture increased up to 14% in mulched treatments over millet monoculture treatments. All yield increases were achieved without the addition of fertilizers or nutrient amendments. In an attempt to mimic local practices our experiment was rainfed and no soil amendments were introduced. / Master of Science

With a rapidly growing world population and increased threats of climate change, Sub-Saharan Africa is most at risk for lower crop yields and facing hunger. Within Sub-Saharan Africa, Senegal has some of the highest levels of anemia and micronutrient deficiencies among women and children. Mungbean [Vigna radiata (L.) R. Wilczek] is a pulse crop that has recently been successfully introduced in Senegal to diversify a primarily cereal-based diet consisting of millet, maize, and rice. The potential for mungbean to be harvested as a leafy green as well as a pulse could allow for a more balanced and nutrient-rich diet. This diversification could help combat micronutrient deficiencies while earlier harvest of the leaves could help alleviate the pressures of the "hunger season." To understand the effects of leaf harvest on mungbean grain yield, yield components, and nutrition, a field trial was conducted in Blacksburg, Virginia for three consecutive years from 2020 to 2022. In a split-plot design, four frequencies of leaf harvest (0x, 1x, 2x, and 3x) on seven accessions of mungbean were tested in triplicate. The objective of this experiment was to determine if mungbean can be used as a dual-purpose crop as a leafy green vegetable without decreasing grain yield in Senegal. It was found that mungbeans could undergo up to two leaf harvest of immature leaves without reducing yield, total dry matter (TDM), or yield components. The harvested leaves were also found to be highly nutritious with 22.0% protein, 12.3% fiber and 8.5% ash with no significant differences between leaf harvest treatments. These results indicate that mungbean can be used as a dual-purpose crop for harvest as leafy greens and pulse in Senegal. Further, mungbeans were studied as a viable crop in southside Virginia. The objective was to evaluate the efficacy of mungbeans as an alternative crop to tobacco farmers in Virginia. Field trials were conducted on farmers' fields and at Virginia Tech's Southern Piedmont Agricultural Research and Extension Center in 2021 and 2022. A split-plot experimental design was used with early and late planting dates in the beginning and end of June as the whole plots and two commercially-available cultivars, Berken and OK 2000, as the sub-plots. Due to highly variable rain patterns in 2021 and 2022, as well as differing management practices, there were no consistent effects of genotype or planting date on yield, plant height, pods per plant, seeds per pod, or seed size. Yield ranged from 0.19 MT ha-1 to 1.18 MT ha-1 with an average yield of 0.84 MT ha-1 in 2021 and 0.38 MT ha-1 in 2022. Though there was variation in yield, across planting dates, cultivars, locations, and years, the highest yield was higher than global averages. It was concluded that while there is great potential with the growing mungbean market, more studies of breeding and supply chain issues and development of a production guide are needed for mungbean to be successful in Virginia. A final study compared soybean, edamame, and mungbean nutritional components and volatiles, two characteristics of importance to breeding objectives and food processing regarding plant alternative proteins. It was found that mungbean had significantly less protein (21.1%) than soy (36.2%) and edamame (38.3%). Mungbean also had lower fat (0.769%) compared to soy (13.5%) and edamame (14.0%). Analysis of aromatic compounds revealed that soybean, edamame, and mungbean each had unique profiles that could be advantageous to the production of specific plant protein foods. Overall, these studies demonstrate the growing importance and potential of mungbean in both Senegal and in the United States. / Master of Science / With a rapidly growing world population and increased threats of climate change, Sub-Saharan Africa is most at risk for lower crop yields and facing hunger. Within Sub-Saharan Africa, Senegal has some of the highest levels of anemia and micronutrient deficiencies among women and children. Mungbean [Vigna radiata (L.) R. Wilczek] is a pulse crop that has recently been successfully introduced in Senegal to diversify a primarily cereal-based diet consisting of millet, maize, and rice. The potential for mungbean to be harvested as a leafy green as well as a pulse could allow for a more balanced and nutrient-rich diet. This diversification could help combat micronutrient deficiencies while earlier harvest of the leaves could help alleviate the pressures of the "hunger season." To understand the effects of leaf harvest on mungbean grain yield, yield components, and nutrition, a field trial was conducted in Blacksburg, Virginia for three consecutive years from 2020 to 2022. In a split-plot design, four frequencies of leaf harvest (0x, 1x, 2x, and 3x) on seven accessions of mungbean were tested in triplicate. The objective of this experiment was to determine if mungbean can be used as a dual-purpose crop as a leafy green vegetable without decreasing grain yield in Senegal. It was found that mungbeans could undergo up to two leaf harvest of immature leaves without reducing yield, total dry matter (TDM), or yield components. The harvested leaves were also found to be highly nutritious with 22.0% protein, 12.3% fiber and 8.5% ash with no significant differences between leaf harvest treatments. These results indicate that mungbean can be used as a dual-purpose crop for harvest as leafy greens and pulse in Senegal.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

Drought, salinity, and low soil fertility have negative impacts on agricultural productivity, resulting in food scarcity and nutritional insecurity, particularly in Sub-Saharan Africa. Mungbean [Vigna radiata (L.) R. Wilczek] has seen increased interest as a short-duration and drought tolerant legume crop, capable of atmospheric N₂ fixation. Mungbean is a protein and iron-rich legume and can be used as vegetable or grain for human consumption or multipurpose crop. At present, few studies have simultaneously explored the best agronomic practices for mungbean cultivation and evaluated its potential for increasing crop yields via intercropping systems and improving soil fertility through biological N₂ fixation. To understand the agronomic practices and soil physical properties limiting mungbean production, the impacts of two mungbean cultivars (Berken and OK2000) with and without inoculation with Bradyrhizobium spp. grown in loamy sand and silt loam soils on mungbean growth and yield were investigated under glasshouse conditions. Promising results from this study led to the introduction of mungbean into pearl millet systems in Senegal and evaluation of the effects of intercropping on growth, yields, land equivalent ratio (LER), canopy cover estimates, and normalized difference vegetation index (NDVI). Finally, we evaluated plant growth and N₂ fixation of five mungbean genotypes grown in two soil textures using the ¹⁵N natural abundance technique leading to recommendations for those with the greatest overall benefit to the cropping system. The literature review shows mungbean often proposed as a strategic crop for increasing legume diversification within current cropping systems and providing increased food security as well as market diversification and economic sustainability. The greenhouse study revealed that OK2000 cultivar produced significantly higher yield when inoculated and planted on a silt loam soil than other treatments, indicating the importance of inoculation and soil texture in mungbean establishment. Intercropping mungbean and millet significantly (p≤ 0.05) increased combined yields (35% to 100% increase) and LER compared to sole millet cropping systems. Canopy cover estimates and NDVI values significantly increased up to 60% and 30%, respectively, in millet-mungbean intercropping over millet alone. The N2 fixation study showed that %Ndfa of mungbean was higher when grown in the loamy sand soil (27% increase). However, soil N uptake (235 mg plant⁻¹) and amount of N fixed (67 mg plant⁻¹) were greater in the silt loam soil. Among genotypes, IC 8972-1 significantly (p≤ 0.05) derived less N from the atmosphere (23%) but took more soil N (155 mg plant⁻¹) which yielded significantly greater dry biomass (7.85 g plant⁻¹) and shoot N content (200 mg plant⁻¹). The results from the N₂ fixation study indicated that choice of mungbean genotype can contribute to reducing N needs of agricultural systems. Overall, this research project demonstrated that mungbean has the potential for diversifying smallholder agriculture and adding biologically fixed N into soils, in line with transformative adaptation strategies being promoted for sustainable agriculture. Further research and development programs on good cultural practices, adaptation to cropping systems, and nutritional benefits for human consumption can promote mungbean cultivation in SSA. / Doctor of Philosophy / Global population growth is expected to reach 9.8 billion in 2050 while climate change is predicted to reduce food production. Sustainable solutions are needed for increasing food availability and satisfying nutritional needs under changing climatic conditions. Mungbean is a viable option because it is a legume crop capable of restoring soil fertility and has low water requirements. Mungbean also contains high levels of protein and iron and can, therefore, provide a nutritious and healthy food. Although the agronomic benefits of mungbean have been studied, best cultural practices and its impact on farming systems and soil fertility are scattered. The objectives of this research were to identify the best agronomic practices for mungbean production, assess its effects when grown together with millet, and measure its nitrogen contribution to the soil. The results showed that selecting the best genotypes to be grown in a particular soil texture can significantly increase mungbean growth and yield. In addition, incorporation of mungbean into cereal-based farming systems demonstrated its capacity for improving agricultural production in a low-input environment. Assessment of nitrogen fixation by mungbean showed that it can naturally add nitrogen into the soils, the most limiting plant nutrient, reducing nitrogen application needs. Thus, the ability of mungbean to diversify farming systems, improve soil fertility, and deliver nutritious food will provide agronomic, environmental, and economic benefits to farmers, especially in food-insecure households. However, exploitation of the full potential of mungbean won't be achieved without understanding the major factors influencing mungbean cultivation and production.