Integrating conservation agriculture with intensive crop diversification in the maize-based organic system: Impact on sustaining food and nutritional security

Introduction: Developing an intensive sustainable model and feeding a rising population are worldwide challenges. The task is much more daunting in the North Eastern Himalayas, where, low productive maize (Zea mays)- fallow is the main production system in the upland. To increase farm productivity, nutritional security, and energy dietary returns while maintaining environmental sustainability and economic viability, short-duration crops must be included in the maize-fallow system. Methods: A field study was conducted in sandy clay loam soil with a randomized complete block design with three replications for three continuous years (2018-2021) under organic management with two crop management practices, viz., (i) conservation agriculture and (ii) conventional agriculture, and six crop diversification options, viz., (i) maize-sweet corn (Zea mays saccharata)-vegetable pea (Pisum sativa) (M-SC-VP), (ii) maize-sweet corn-mustard (Brassica juncea) (M-SC-M), (iii) maize-sweet corn-lentil (Lens culinaris) (M-SC-L), (iv) maize-sweet corn-vegetable broad bean (Vicia faba) (M-SC-VB), (v) maize (local)-vegetable pea (M-VP), and (vi) maize (local)-fallow (M-F). Results: The results showed that, the average system productivity was 5.3% lower for conventional agriculture than conservation agriculture. System carbohydrate, protein, fat, dietary fiber, and dietary energy were similar to 6.9, 6.8, 7.8, 6.7, and 7%, higher in conservation agriculture than in conventional agriculture, respectively. Similarly, system macronutrients (Ca, Mg, P, and K) and system micronutrients yield (Fe, Mn, Zn, and Cu) were, 5.2-8% and 6.9-7.4% higher in conservation agriculture than in conventional agriculture, respectively. On average, over the years, crop diversification with M-SC-VP/M-SC-VB intensive crop rotation had higher system productivity (158%), production efficiency (157%), net returns (benefit-cost ratio) (44%), and dietary net energy returns (16.6%) than the local maize-vegetable pea system. Similarly, the M-SC-VP/M-SC-VB system improved the nutritional security by improving Ca, Mg, P, K, Fe, Mn, Zn, and Cu yield by 35.5-135.7% than the local M-VP system. Discussion: Conservation agriculture with M-SC-VP/M-SC-VB rotation showed significantly (p<0.05) higher productivity, carbohydrate yield, protein yield, fat yield, and dietary fiber production. It is concluded that conservation agriculture improved soil health and performed better than conventional agriculture in maize-based intensive cropping systems. Overall results indicate that crop diversification with M-SC-VP/M-SC-VB can potentially increase calorie and protein consumption and farm profitability.