Nutrient management strategy in rice–chickpea system for improving chemical and biological properties of lateritic soil

Abstract

AbstractField experiments were conducted during 2013–2015 under a long‐term organic and inorganic fertilization experiment established in 2009 at Kharagpur in India to assess the impact of rate and application timing of organic and inorganic nutrient sources on changes in fertility of lateritic soils. Vermicompost (VC), crop residue (CR), vermiwash (VW), and Azotobacter (AZ) were used as organic sources and chemical fertilizers (CF) as inorganic sources. The nine treatments were Control, CF at 100% N, P, and K (CF 100), VC at 100% N applied onetime as basal (VC‐b100), VC at 100% N applied in two splits (VC 100), VC 50+CF 50, CR, CF 50+CR, VC 50+CR, and VC 50+VW+AZ. After 2 yr of rice (Oryza sativa L.)–chickpea (Cicer arietinum L.) system, significant increase in soil pH (from 5.43 to 5.72) and soil organic carbon (SOC) content (from 3.3 g kg‐1 to 3.8 g kg‐1) was noted with VC100, compared to CF100 (from 5.21 to 5.08 for pH and 3.1 to 2.9 g kg‐1 for SOC). Further, the total soil N content decreased from their initial values in all the nutrient treatments, except VC100, which registered an accumulation of 22 kg ha‐1 over its initial value (874 kg ha‐1). The VC‐based nutrient treatments had significantly higher soil available micro‐nutrients content (Fe, Zn, and Mn) compared to their initial levels. The VC‐based treatments significantly reduced accumulation of heavy metals (available Pb and Ni) content in soil compared to inorganic nutrient treatments. This nutrient management strategy could reduce environmental risk associated with synthetic chemical fertilizers.