Sustainable management of Calcareous soil with conservation agriculture under rice-maize cropping system

Abstract

Sustainable intensification of rice–maize systems is essential for meeting future food demands while maintaining soil health. In calcareous soils, high pH and calcium carbonate content hinder the nutrient availability for the crops. In this scenario, evaluating depth wise (0-10, 10-20 and 20-30 cm) soil fertility status after fifteen years long-term experimentation on tillage and residue management would be an essential strategy to sustain soil health. Treatments included: zero tillage direct seeded rice/zero tillage maize (T1: ZTDSR/ZTM, 25% residue retention), permanent bed direct seeded rice/permanent bed maize with residue retention (T2: PBDSR/PBM, 50% rice + 25% maize residue retention), PBDSR/PBM without residue (T3: PBDSR/PBM, no residue retention), and puddled transplanted rice/conventionally tilled maize (T4: PTR/CTM). Results indicated that PBDSR/PBM+R significantly improved the different physico- chemical properties of soil over conventional method. The treatment with PBDSR/PBM+R showed percent changes in pH, OC, available nitrogen (N), phosphorous (P), potassium (K), sulphur (S) -2.9, 34.8, 11.8, 24.3, 111.9 and 54.4, respectively, in surface soils over conventional method (PTR/CTM). The Depth- wise analyses indicated nutrient stratification, with surface enrichment under residue-retained systems. The pH, CaCO3 and BD was found to increase with depth while OC, available N, P, K, S and micronutrient cations declined. The findings indicate that long-term conservation tillage with crop residue retention improved the nutrient availability in root zone of calcareous soil, while, there was decline in nutrient availability under conventional methods.