Land forming and tillage effects on soil properties and productivity of rainfed groundnut (Arachis hypogaea L.)–rapeseed (Brassica campestris L.) cropping system in northeastern India

Abstract

Soil erosion, low phosphorus fertility, and soil moisture stress during winter season are among major limitations to high crop production and sustainable land management in North Eastern Hill (NEH) region of India. Thus, a two years (2009–2011) field study was conducted on a terraced land (980m a.s.l.) to study the impact of land configuration, tillage and residue management on soil properties under rainfed groundnut–rapeseed cropping system. The treatments were: (i) farmers’ practice (FP) (flat bed – residue removal, 3–4 times ploughing); (ii) broad bed and furrow (BBF) with in situ residue incorporation; (iii) BBF with in situ residue+hedge leaves {white hoary pea, Tephrosia candida (Roxb.) DC} incorporation; (iv) BBF with in situ residue+hedge leaves mulching (no-till, NT); (v) raised bed (RB) with in situ residue incorporation; (vi) RB with in situ residue+hedge leaves incorporation; (vii) RB with in situ residue+hedge leaves mulching (NT). Soil profile moisture content was higher under residue retention/incorporation and altered land configuration than that under FP. Water infiltration rate (11.2mm/h) and hydraulic conductivity (6.98mm/h) in soil under RB with residue+hedge leaves mulching (NT) were significantly higher (P=0.05), than that under FP (7.65mm/h and 3.35mm/h) after two cropping cycles. Soil microbial biomass carbon (SMBC) was significantly higher under RB with residue+hedge leaves incorporation (381μg/g soil and 276μg/g soil) than that under FP. Dehydrogenase activity (DHA) was the highest in RB with residue+hedge leaves mulching (NT) (57.8μgTPF/g soil/24h). Soil organic carbon (SOC) and nutrient content improved under residue management. RB with residue+hedge leaves mulching (NT) resulted in the maximum SOC stock, and it was 2.0Mg/ha and 2.7Mg/ha higher than that of the antecedent level and FP, respectively. The average groundnut equivalent yield (GEY) was significantly the highest in RB with residue+hedge leaves incorporation (2815kg/ha) followed by that under RB with residue incorporation (2747kg/ha). Water use efficiency (WUE) of rapeseed was the maximum in RB with residue+hedge leaves incorporation (4.64kg/ha – mm) and the minimum under FP (1.49kg/ha – mm). The BBF and RB land configurations along with residue and hedge leaves mulching under NT improved soil quality and was the most suitable for higher returns of groundnut–rapeseed system under rainfed mid-hills condition.