12 pages, via Online journal, Corn (Zea mays) grown in the southern Piedmont requires 200 to 280 kg nitrogen (N) ha−1 annually and requires up to 0.87 cm of water per day, making groundwater systems susceptible to nitrate (NO3−) leaching. A perennial white clover (Trifolium repens L.) living mulch (LM) system may reduce NO3-N leaching by using legume N to replace mineral N, though little information is available on such a system in the southern Piedmont. Therefore, a HYDRUS-1D model was used to simulate water and NO3-N flux in three cover crop systems. Cereal rye (Secale cereal L.) (CR), crimson clover (Trifolium incarnatum L.) (CC), and a white clover LM were fertilized with 280, 168, and 56 kg N ha−1. The HYDRUS-1D model was calibrated and validated with observed water contents and NO3-N data that were collected over two years. Water and NO3-N flux models were created for each treatment and evaluated using coefficient of determination, percentage bias, and index of agreement, and showed good agreement to observed data. Nitrate leaching below 1 m in 2015/2016 was 23.5, 12.7, and 21.4 kg ha−1 for the CC, LM, and CR treatments, respectively, but was less than 1 kg ha−1 for all treatments in 2016/2017 due to prolonged drought. Differences in leached NO3-N among treatments were attributed to variation in mineral N application rate and NO3-N uptake by cover crops. Overall, results suggest that the use of a perennial LM system may reduce NO3-N leaching when compared to annual CC and CR cover crop systems.
9pgs, Soil loss due to crop harvest contributes to land degradation, and knowledge of this challenge can guide the choice of crops for sustainable agriculture. Nigeria is the largest producer of cassava (Manihot esculenta Crantz) and the third largest producer of peanut (Arachis hypogaea Linn) in the world. Due to limited information on soil loss during peanut and cassava harvests worldwide, and cost of nutrient loss, a two-year field experiment was conducted to compare soil loss due to harvesting of peanut and cassava and to estimate cost of nutrient loss due to crop harvest under traditional agriculture. Peanut pod yields of 2.39 and 2.08 t ha–1harvest–1 removed 0.62 and 0.58 t ha–1 harvest–1 during peanut harvest, respectively, for years 1 and 2. Similarly, cassava yields of 22.71 and 21.40 t ha–1 harvest–1 removed 1.11 and 0.91 t ha–1harvest–1 during cassava harvest, respectively, for years 1 and 2. Crop yields strongly correlated with soil loss due to peanut harvest (R2= 0.36; p < 0.001) and soil loss due to cassava harvest (R2 = 0.23; p < 0.01). Significantly higher soil loss due to cassava harvest compared to peanut harvest can be ascribed to higher cassava yield. Also, soil nutrient loss due to crop harvest was significantly (p < 0.001) higher for cassava compared with peanut by 27.6% phosphorus (P) and 73.7% potassium (K) for the first year and 39.2% P and 79.1% K for the second year. Fertilizer equivalent cost of P and K losses due to cassava harvest for the two years was higher than that of peanut by US$29 ha–1. The study indicated that the intensity of nutrient loss by harvesting is largely dependent on the crop type, and harvesting of cassava can deplete soil nutrients faster than that of peanut under traditional agriculture. Sequential planting of cassava (deep rooted crop) followed by peanut (shallow rooted crop) as a crop rotation management practice is recommended to mitigate soil loss due to continuous harvesting of cassava, and harvesting with thorough shaking technique is also suggested to reduce nutrient loss potential of crop harvesting.
6 pages, via Online journal, Most agricultural soils are depleted of their soil organic matter (SOM) reserves. A severe loss of SOM content may degrade soil functionality, its capacity for provisioning of essential ecosystem services, and soil health. Therefore, restoration of SOM content in soils of agroecosystems may reverse the degradation trends, enhance ecosystem services (Banwart et al. 2015), and advance Sustainable Development Goals of the United Nations. (Lal et al. 2018a). Increase in SOM content may also partially replace the use of chemical fertilizers and supplemental irrigation, while restoring the environment.
3 pages, via online journal, The fast-moving coronavirus disease 2019 (COVID-19) pandemic engulfed the world within four months from December to March of 2020, with long-lasting impacts on social, economic, political, educational, and scientific programs. It exacerbated risks of food and nutritional insecurity for a large segment of society, and threats of disruption in the food supply chain may be aggravated by climate change, soil degradation, and the flood/drought syndrome. Ensuring adequate access to nutritious food is a daunting challenge even in developed/scientifically advanced countries, and is a sheer tragedy in poor nations.
