Land productivity and water use efficiency of maize-soybean strip intercropping systems in semi-arid areas: A case study in Punjab Province, Pakistan

Intercropping improves crop productivity in dryland farms, but little information is available on its application to irrigated land. Therefore, a three-year field trial was conducted to compare two maize-soybean strip-intercropping planting patterns (two-rows of maize intercropped with two-rows of soybean [2M2S] or -three rows of soybean [2M3S]) were studied with sole maize (SM) and sole soybean (SS) systems. Our results showed that wider-strips of soybean grown as 2M3S had significantly higher leaf area index (LAI; 19%), total dry matter accumulation (TDM; 15%), and grain yield (21%) than the narrower 2M2S strips; this is likely related to the reduced effects of maize shading on soybean. Slightly decreased LAI (4%), TDM (8%), and grain yield (5%) of maize were found in 2M3S. On average, intercropped maize and soybean produced 80% and 52% in 2M2S and 76% and 63% in 2M3S compared to SM and SS yields, respectively, demonstrating the dominance of maize over soybean when intercropped. Similarly, maize was a stronger competitor for water than soybean, with partial water equivalent ratio of 0.81 in 2M2S and 0.78 in 2M3S, while that of soybean was 0.54 in 2M2S and 0.66 in 2M3S. In the intercropping systems, the land equivalent ratio ranged from 1.31 to 1.45, and the water equivalent ratio ranged from 1.32 to 1.49, exhibiting that maize-soybean strip-intercropping is a productive strategy to maximize water use efficiency. The results suggest that the maize-soybean strip-intercropping system may be a productive and sustainable strategy to improve the water use efficiency and land productivity under irrigated conditions. This strategy could benefit agriculture with cleaner, and more efficient production under a global scenario of constrained land and water resources. However, more studies are needed to evaluate the feasibility of intercropping systems in various growing conditions.