Effects of Tillage and Residue Management Practices on Soil and Root Parameters in Soybean (Glycine max)–Wheat (Triticum aestivum) Cropping System

Abstract

A field study was conducted during 2009–2011 to investigate the effect of tillage, crop establishment and residue management practices on soil and root parameters in soybean-wheat cropping system. The experiment was conducted with 4 main plot treatments of tillage and crop establishment techniques as conventional tillage-flat (CT-F), zero tillage-flat (ZT-F), conventional tillage-bed (CT-B) and zero tillage-bed (ZT-B); and 4 sub plot treatments of residue application as control, wheat residue (3 t ha−1), soybean residue (3 t ha−1) and soybean + wheat residue (3 t ha−1 each). The infiltration rate was significantly higher with ZT-F (1.22 cm h−1) and wheat + soybean residue application (1.16 cm h−1). ZT-F and ZT-B recorded higher mean weight diameter and geometric mean diameter at 0–10 cm than that of CT-F and CT-B. The percentage of micro-aggregate was higher with CT-F and CT-B at all depths while the macro-aggregate was high with ZT-F and ZT-B up to 30 cm soil depth. The microbial biomass carbon in ZT-F and ZT-B was 216.3 and 214.6 µg g−1 of soil, respectively which was significantly higher than that of CT-F and CT-B. The wheat + soybean residue application recorded 19.6 % higher MBC than the control. Among the tillage treatments, ZT-F performed well with regard to root length density as 2.38 and 1.11 cm cm−3, root surface area as 0.67 and 0.36 cm2 cm−3, root volume density as 19.22 and 8.26 × 10−3 cm3 cm−3 and average root diameter as 1.06 and 0.81 mm by soybean and wheat, respectively. Similarly, wheat + soybean residue also performed better than the no residue treatment.