Soil Carbon Sequestration and Crop Yields in Rice–Wheat and Sugarcane–Ratoon–Wheat Cropping Systems Through Crop Residue Management and Inoculation of Trichoderma viride in Subtropical India

A field experiment was conducted at ICAR-IISR, Lucknow, in a split-plot design with two cropping systems and eight different crop residue management practices. In main plots, cropping systems, viz. CS1—rice–wheat (R–W) and CS2—sugarcane (plant crop)–ratoon–wheat (S–R–W) and subplots residue management practices, viz. residue removal (T1-RR); residue burning (T2-RB); residue incorporation (T3-RI); residue incorporation + Trichoderma (T4-RI + T), residue incorporation +25 % extra nitrogen application (T5-RI + N), partial residue incorporation (T6-PRI), partial residue incorporation + Trichoderma (T7-PRI + T) and partial residue incorporation +25 % extra nitrogen application (T8-PRI + N), were allocated. The observations on soil physical parameters indicated the lower mean bulk density (1.10 Mg m−3) in sugarcane–ratoon–wheat system than the rice–wheat system (1.145 Mg m−3). Increased porosity (58.68 %) was obtained in sugarcane–ratoon–wheat (S–R–W) system as compared to rice–wheat system (56.83 %). In S–R–W system, higher (19.51 %) SOC was recorded than the R–W system (16.31 Mg ha−1) at 0–15 cm depth. After harvesting of wheat in both the cropping systems, higher total carbon sequestered (@1.42 Mg ha−1) in S–R–W system than the R–W cropping system (0–15 cm soil depth). Higher contents of available nitrogen, phosphorous and potassium were recorded in S–R–W system than the R–W system after completion of crop cycle. The agronomic efficiency of rice, wheat and sugarcane crops indicated the higher level with residue incorporation along with Trichoderma application. Thus, it could be concluded that sugarcane–ratoon–wheat system acted as soil fertility restorer and crop reside management along with application of Trichoderma sustained the soil carbon level, crop productivity and agronomic/production efficiency of N for longer period.