Influence of Nitrogen Application on Soil Chemical Properties, Nutrient Acquisition, and Enzymatic Activities in Rainfed Wheat/Maize Strip Intercropping

The efficient utilization of input resources is imperative to harvest optimum crop yield on a sustainable basis. Intercropping is a sustainable agronomic practice to achieve higher yields with efficient utilization of available resources. A 2-year field study was conducted to investigate the effect of wheat-maize intercropping under different nitrogen (N) application rates. The experiment included three intercropping treatments, viz., sole wheat (WMC), sole maize (MMC), and maize-wheat intercropping (IM-W), and two N application rates, viz., control without N application (− N) and full dose of N (+ N), basal application at 150 and 235 kg ha⁻¹ for wheat and maize, respectively, for both mono- and inter-crops). The IM-W system increased N accumulation by 19.87 and 7.20%, and 16.63 and 6.58%, phosphorus (P) accumulation by 73.05 and 78.80%, and 69.75 and 24.50%, potassium (K) accumulation by 20.50 and 7.49%, and 17.70 and 7.22% (averaged for N rates) in 2019 and 2020, as compared to that of the WMC and MMC systems, respectively. Overall, the IM-W system increased total N by 9.36 and 6.95%, Olsen P by 25.54% and 21.78%, and exchangeable K by 14.63% and 7.96% compared to WMC and MMC, respectively. The mean increase in the activities of urease, acid phosphatase, nitrate reductase, sucrase, catalase, polyphenol oxidase, and invertase for intercropping treatment (averaged for N rates and both years) was 7.56 and 4.43%, 38.47 and 16.26%, 64.60 and 44.17%, 19.39 and 7.75%, 119.21 and 34.31%, 194.44 and 86.36%, and 144.82 and 40.53%, respectively, over WMC and MMC treatments. Growing wheat in combination with maize under rainfed conditions is an attractive agronomic practice for improving nutrient acquisition, soil chemical properties, and enzymatic activities.