Nutrient recycling potential of rock phosphate and waste mica enriched compost on crop productivity and changes in soil fertility under potato–soybean cropping sequence in an Inceptisol of Indo-Gangetic Plains of India

Abstract

This manuscript focuses on the nutrient recycling potential of enriched compost prepared using rice straw, low-grade rock phosphate (RP) and waste mica along with Aspergillus awamori and their effect on crop productivity and changes in soil fertility under potato–soybean cropping sequence in an Inceptisol of Indo-Gangetic Plains of India. Enriched composts had higher total as well as bioavailable P and K content than ordinary compost. Data emanated from the field study revealed that yield and uptake of N, P and K by potato tubers were significantly increased due to application of inorganic fertilizer and enriched compost over control. Application of 50% recommended dose of NPK fertilizers (RDF) along with 4.0 Mg ha−1 of enriched compost product-C prepared by rice straw + RP @ 4% P + waste mica 4% K + Aspergillus awamori resulted in 43.3% additional yield and 102.3, 67.0 and 62.2% additional N, P and K uptake by potato over control, respectively. Significant increase in yield and uptake of N, P and K by soybean grown on residual fertility were also observed over control. Post-harvest soil analysis indicated a significant build-up in soil organic C, available N, P and K due to application of enriched compost in combination with inorganic fertilizer over 100% RDF. The results clearly showed that enriched compost could be an alternative and cost effective option to prepare a value added product using agricultural wastes and low-grade minerals like RP and waste mica in place of costly chemical fertilizer for crop production and maintaining soil fertility.