Effect of tillage and residue management on properties of two coarse-textured soils and on yield of irrigated wheat and groundnut

Abstract

Changes in soil properties and yield response in relation to tillage and residue management treatments in an irrigated groundnut ( Arachis hypogea L.)—wheat ( Triticum aestivum, L.) rotation on a sandy soil (1972–1974) and on a sandy loam soil (1974–1976) were evaluated. Tillage treatments (T 1 and T 2) did not cause significant changes in soil properties. Incorporation of crop residues (5 t residue per ha per crop, T 3) caused a substantial increase in organic C, available N, and NaHCO 3 -extractable P contents in the top 15 cm of both soils. Residue management treatments (T 3, T 4 and T 5) showed no significant effect on soil bulk density and exchangeable K. Crop yields under no-tillage (T 1) and conventional tillage (control, T 2) were comparable on sandy soil but on the sandy loam soil, no-tillage yielded significantly lower than conventional tillage. Compared with the control, incorporation of crop residues (T 3) caused higher yields on sandy soil for groundnut and wheat by 34.1 and 47.4%, respectively, and on sandy loam by 17.1 and 7.2%, respectively. Mulching with crop residues conserved soil moisture and reduced maximum soil temperature (1.5–5.3°C in groundnut and 1.5–2.9°C in wheat) but other measured soil properties were not significantly affected. Significant yield increase due to residue mulching (T 4) was observed in sandy soil but it was significantly less than when total crop residue was incorporated (T 3). Increased wheat root-weight density in the top 15 cm soil with residue mulching was not reflected in grain yield. Compared with the incorporation of the total amount of crop residue (T 3), incorporation of half the amount and application of the other half as mulch (T 5) caused lower yields — on sandy soil for groundnut and wheat by 31.5 and 15.7%, respectively, and on sandy loam by 4.8 and 3.6%, respectively.