Double no-till and rice straw retention in terraced sloping lands improves water content, soil health and productivity of lentil in Himalayan foothills

Abstract

Designing suitable conservation tillage and rice straw management practices are vital to conserve limited soil water in sloping terraced lands for growing a second crop like lentil (Lens esculentum L.) after rice (Oryza sativa L.). A field study was conducted to evaluate the effects of tillage, rice straw management and supplemental irrigation on soil physico-chemical properties and productivity of lentil grown in rice fallow land. The maximum soil water content in lentil was observed in plots under rice residue retention as mulch (@ 5 Mg ha−1) which was followed by 20 cm standing rice stubble and residue removal. Rice residue retention and 20 cm standing stubble also increased infiltration rate, cumulative infiltration and sorptivity. Adoption of double no-till (NT) for rice and subsequent lentil crop increased soil organic carbon (SOC) concentration by 2.8%, 3.4% and 7.4% at 0–5, 5–10 and 10–15 cm soil depth, respectively than those under conventional tillage (CT). Soil available nitrogen and phosphorus contents were higher under residue retention either as mulch or standing rice stubble as compared to residue removal. Double NT and added residues (mulch and 20 cm standing stubble) increased soil microbial biomass carbon and dehydrogenase activity than CT without rice residues. Application of one supplemental irrigation did not significantly influence the soil properties. The NT in both rice and lentil enhanced lentil yield by 10–18% than lentil grown after rice under CT. Rice residue retention as mulch @ 5 Mg ha−1 and 20 cm standing rice stubble gave 35–42% and 23–27% higher lentil yield against residue removal over the years, respectively. Therefore, NT in both rice and subsequent lentil along with rice residue retention @ 5 Mg ha−1 as mulch or 20 cm standing stubble would pay substantial dividends for improving the soil health, enhancing lentil productivity and ensuring double cropping in rice fallow areas of Himalayan foothills and in similar agro-ecologies elsewhere.