Conservation agriculture based integrated crop management sustains productivity and economic profitability along with soil properties of the maize-wheat rotation

Abstract

Field experiments were conducted to evaluate eight different integrated crop management (ICM) modules for 5 years in a maize-wheat rotation (M_WR); wherein, ICM_1&2-'business-as-usual' (conventional flatbed maize and wheat, ICM_3&4-conventional raised bed (CT_RB) maize and wheat without residues, ICM_5&6-conservation agriculture (CA)-based zero-till (ZT) flatbed maize and wheat with the residues, and ICM_7&8- CA-based ZT raised bed maize and wheat with the residues. Results indicated that the ICM_7&8 produced significantly (p < 0.05) the highest maize grain yield (5 years av.) which was 7.8-21.3% greater than the ICM_1-6. However, across years, the ICM_5-8 gave a statistically similar wheat grain yield and was 8.4-11.5% greater than the ICM_1-4. Similarly, the CA-based residue retained ICM_5-8 modules had given 9.5-14.3% (5 years av.) greater system yields in terms of maize grain equivalents (M_GEY) over the residue removed CT-based ICM_1&4. System water productivity (S_WP) was the highest with ICM_5-8, being 10.3-17.8% higher than the ICM_1-4. Nevertheless, the highest water use (T_WU) was recorded in the CT flatbed (ICM_1&2), ~ 7% more than the raised bed and ZT planted crops with or without the residues (ICM_4-8). Furthermore, the ICM_1-4 had produced 9.54% greater variable production costs compared to the ICM_5-8, whereas, the ICM_5-8 gave 24.3-27.4% additional returns than the ICM_1-4. Also, different ICM modules caused significant (p < 0.05) impacts on the soil properties, such as organic carbon (S_OC), microbial biomass carbon (S_MBC), dehydrogenase (S_DH), alkaline phosphatase (S_AP), and urease (U_RE) activities. In 0.0-0.15 m soil profile, residue retained CA-based (ICM_5-8) modules registered a 7.1-14.3% greater S_OC and 10.2-17.3% S_MBC than the ICM_1-4. The sustainable yield index (S_YI) of M_WR was 13.4-18.6% greater under the ICM_7&8 compared to the ICM_1-4. Hence, this study concludes that the adoption of the CA-based residue retained ICMs in the M_WR could sustain the crop yields, enhance farm profits, save water and improve soil properties of the north-western plans of India.