Diversified cropping systems for reducing soil erosion and nutrient loss and for increasing crop productivity and profitability in rainfed environments

CONTEXT: Globally, rainfed regions encounter several constraints that limit crop production. Poor and degraded soils resulting from soil erosion are one among them. We hypothesized that a diversified cropping system in rainfed drylands can reduce soil erosion and improve soil health and crop productivity and meet the food security needs of rainfed farmers. OBJECTIVE: The study aimed to assess potential diversified cropping systems in terms of reducing soil erosion and water and nutrient losses, and increasing crop and systems productivity and profitability. METHODS: The study was carried out at the Gungal Research Farm of ICAR Central Research Institute for Dryland Agriculture (17 o 05 ' N, 78 o 39 ' E) from 2015 to 16 to 2020 - 21. The study investigated seven diversified cropping systems (treatments): sorghum + pigeon pea- hedge lucerne, sorghum + pigeonpea- guinea grass, castor- hedge lucerne, castor- guinea grass, sorghum- fodder clusterbean- fodder cowpea- fodder horsegram, sole sorghum, and sole pigeonpea. Multi -criteria assessments were conducted to understand trade-offs related to soil nutrients and their losses, and productivity and profitability of various annual and perennial based systems. RESULTS AND CONCLUSIONS: Among the various systems evaluated, sole sorghum was the most sensitive to soil erosion, leading to highest amount of nutrient loss in all years (87.5, 47.3, and 9.8 kg N, P and K ha - 1 in 2019-20, 102.4, 58.2, 14.2 kg N, P and K ha -1 in 2020-21, and 78.6, 39.2, 6.16 kg N, P and K ha -1 in 2021-22). The perennial based cropping systems with more diverse crops and greater land cover that included sorghum + pigeonpea - guinea grass and sorghum + pigeon pea - hedge lucerne had the lowest amount of nutrient loss. The least cumulative monetary value of nutrient loss was in sorghum + pigeon pea - hedge lucerne (137.11 US$) followed by sorghum + pigeonpea - guinea grass (145.33 US$). The systems with diverse crops reduced runoff and soil erosion, improved soil health, and increased crop and systems productivity and profitability. The tradeoffs analysis using the radar graphs also showed lower soil loss and improved soil heath in diversified perennial based cropping systems, resulting in increase in net income to US$1981 for sorghum + pigeonpea - hedge lucerne compared to US$909 for sole sorghum. SIGNIFICANCE: Perennial based cropping systems with diverse crops can be an effective strategy to reduce soil erosion and improve soil health, and increase crop and systems productivity in rainfed areas of south India. These results have implications to other countries globally with rainfed climate and dryland farming.