Synergistic influence of minimum tillage and integrated nutrient schedules on crop performance, nutrient uptake, profitability and soil microbial diversity in a rice‒lentil cropping system.

Background: Continuous use of chemical fertilizers in conventional tillage systems has jeopardized soil fertility, affecting productivity of crops. Puddling is currently a serious constraint for farmers in rice based cropping systems because of water deficits and soil structure destruction. Finding an alternative cultivation practice is imperative to improve this scenario for sustainability and food security.

Methods: The current study was conducted in consecutive two years (from 2018-2020) to evaluate the effects of minimum tillage and integrated nutrient schedules on the nutrient uptake, profitability and microbial diversity of the rice‒lentil cropping system in the lower Gangetic plains of West Bengal. The study was carried-out in a split-plot design and repeated all treatments in three times. Treatments such as CT Direct seeded rice - lentil (CT-DSR), MT Direct seeded rice - lentil (MT-DSR), CT Transplanted rice - lentil (CT-TPR) and MT Transplanted rice - lentil (MT-TPR) were assigned in main plots and no application of nutrients (Control), 100% RDF, 75% Nitrogen + FYM (75% N + FYM), 75% Nitrogen + FYM + Azospirillum (75% N + FYM + Azo) and 75% Nitrogen + FYM + Azospirillum + Zinc Sulfate (75% N + FYM + Azo + Zn) were assigned in sub-plots.

Results: The MT treatments significantly gave better growth, yield and nutrient uptake values in the second year with MT- DSRMT-DSR recording highest growth (96.38 cm), yield (5.17 t ha^-1) and nutrient uptake of rice, despite the CT treatments performing better in first year. Minimum tillage treatments showed better growth, yield and nutrient uptake in lentil throughout the experiment with MT-DSRMT-DSR treatment having maximum growth (32.81 cm & 34.98 cm), yield (8.08 q ha^-1 & 8.817 q ha^-1) and nutrient uptake in both years respectively. Treatment of 100% RDF obtained highest growth (96.53 cm & 32.98 cm), uptake and yield (5.17 t ha^-1 & 8.23 q ha^-1) respectively for rice & lentil during the first year, but 75%N + FYM + Azo + Zn surpassed all the other treatments in terms of the aforementioned parameters, in the second year. The MT DSR + 75% N + FYM + Azo + Zn treatment in the pooled analysis over two years had the greatest economic benefit (85,845.27 INR/ha), B:C ratio (1.85) and a Shannon diversity index of 0.070.

Conclusion: The results of the study revealed that, to obtain long term sustained productivity, better soil health and income security of the smallholder farmers of Eastern India, minimum tillage along with integrated nutrient schedules can be a viable alternative in the rice‒lentil cropping system.