Date of Planting, Spacing and Integrated Nutrient Management Practices Improves Soil Microbial Populations and Soil Fertility Status Under Rice -Arhar Cropping System in Acidic Soils of Eastern India

Rice (Oryza sativa L.) is a nutrient-exhausting crop, sustainable productivity of rice based cropping system can be achieved through appropriate nutrient management and crop diversification through incorporation of pulse into this system. Considering the above facts, a field experiment on rice-arhar system was conducted for two consecutive years (2018 and 2019) during kharif seasons at the Agronomy research Farm of Odisha University of Agriculture and Technology, Bhubaneswar having sub-humid climate with two date of planting, three nutrient management and three row spacing. Soil physico-chemical properties like N, soil organic carbon (SOC) was found higher with earlier planting, soil-test-based fertilizer Recommendation (STBFR) + Farmyard Manure (FYM) in rice and 30 cm row spacing in arhar. The system nutrient uptake of 219.76 kg N ha(-1), 38.25 kg P ha(-1) and 197.29 kg K ha(-1) and microbial activities in terms of dehydrogenase activity (DHA) (241.9 mg TPF g(-1) soil 24 hr(-1)), alkaline phosphatase activity (APA) (376.7 mg p-nitrophenol kg(-1) soil 1 h(-1)), microbial biomass Carbon (MBC) (260.3 mu g g(-1) of dry soil), microbial biomass nitrogen (MBN) (93.7 mu g N g(-1) soil) was registered with earlier planting, STBFR + FYM in rice and 30 cm row spacing in arhar. Higher positive N and K balance over initial (actual balance) in rice-arhar cropping system was observed in the treatment fertilized with both organic and inorganic sources of nutrients.

Automated summary

Appropriate nutrient management and crop diversification through incorporation of pulse into rice based cropping system can achieve sustainable productivity. This study found that earlier planting, soil-test-based fertilizer recommendation + farmyard manure in rice, and 30 cm row spacing in arhar resulted in higher soil physico-chemical properties and microbial activities. The combination of organic and inorganic sources of nutrients showed higher positive nitrogen and potassium balance in the rice-arhar cropping system.