Effects of tillage and rice residue management practices on lentil root architecture, productivity and soil properties in India’s Lower Himalayas

Abstract

Large areas in North Eastern Region (NER) of India remain fallow (approx. 2.50 million hectare) after the rainy season (June-October) rice (Oryza sativa L.) could be cultivated in succession with winter pulses like lentil (Lens esculentum L.) on residual soil moisture. Growing short-duration lentil cultivars under no-till (NT) and mulch rice may limit the pulse drought stress. A 2-year study (2011–2013) was conducted in terraced land of Meghalaya, India (950 m ASL), involving rice-lentil cropping system to evaluate on soil and legume parameters short-term impacts of three tillage management prior lentil crop i.e. no tillage (NT), minimum tillage (MT), conventional tillage (CT) and four residue management i.e. residue removal (RM), 20 cm standing rice stubble (20SS), 40 cm standing rice stubble (40SS) and mulch @ 5 Mg ha−1] and two lentil plant types [early and medium duration varieties: DPL 62 (Sheri) and DPL 15 (Priya), respectively]. Soil moisture content, water holding capacity and infiltration rate (IR) were higher in soil under mulch followed by 40 SS compared to 20SS and RM. The IR was significantly higher at lentil harvest for both in soil under NT in rice followed by NT in lentil (NT-NT) as compared to MT in rice followed by NT in lentil (MT-NT), and CT in rice followed by NT in lentil (CT-NT). The soil organic carbon (SOC) concentration, soil microbial biomass carbon (SMBC) and dehydrogenase activities (DHA) were significantly higher in 0–15 cm soil depth under NT-NT and MT-NT as compared to CT-NT. On an average, significantly higher SOC (17.3 g kg−1), DHA (2.32 μg g−1 hr−1) and SMBC (79.5 μg g−1 dry soil) in 0–15 cm soil layer at harvest of lentil were obtained under mulch followed by 40 SS as compared to RM. Lentil leaves chlorophyll and relative water contents were significantly higher under mulch followed by that under 40SS than 20SS and RM. Total root length, surface area and root volume increased significantly under mulch compared with those under RM. Lentil grown with mulch and 40SS recorded significantly higher seeds per pod, pods per plant, 1000 seed weight and lentil seed yield than RM and 20SS. Lentil seed yield recorded under mulch was 66.6 and 36.5% higher than that under RM. We concluded that reduced tillage (MT/NT) and residue retention through mulch or 40SS could be adopted to reduce drought stress lentil constraints in rice successions while physical improving soil properties.