Effect of crop combination on yield performance, nutrient uptake, and land use advantage of cereal/legume intercropping systems

Crop type and temporal synchronization are crucial for improving the productivity of intercropping systems, especially with reduced inputs (nitrogen, N, and phosphorus, P). However, the effects of crop type and temporal dynamics on nutrient uptake and yield advantage of cereal/legume intercropping systems are still unclear. The objective of this study was to assess the effects of different temporal dynamics of intercrops on growth, nutrient-use advantage, land productivity, and economic viability of cereal/legume intercropping systems under arid irrigated conditions. In this field study, we used the equal land proportion for all intercrops in both intercropping systems: wheat/chickpea intercropping (wheat/chickpea), where legume (chickpea) was the first-sown crop; and wheat/soybean intercropping (wheat/soybean), with cereal (wheat) being the first-planted crop), and all strip intercropping results were compared with their sole systems: sole chickpea (SCp), sole wheat (SW), and sole soybean (SS). Here, we revealed that the improved complementarity and facilitation interactions in wheat/chickpea linked with better phenological synchronization between wheat and chickpea, which resulted in higher relative grain yields, primarily gained from greater biomass accumulation and its translocation towards ears/pods, seeds, and seed weight, than the wheat and soybean in wheat/soybean. Similarly, the intercropped wheat accumulated a significantly higher N (15%) and P (14%) under wheat/chickpea than in wheat/soybean, whereas, in legumes, the N and P uptake of chickpea in wheat/chickpea was 19% and 13% higher than that of soybean in wheat/soybean, respectively. On average, in wheat/soybean, wheat and soybean achieved 62% of SW and 58% of SS yields, while in wheat/chickpea, wheat and chickpea produced 71% and 67% of SW and SCp yields, respectively, demonstrating the advantage of sowing legumes earlier than cereals in intercropping systems. Overall, in wheat/chickpea, the system-level nutrient- and land-use advantage, measured as the land, nitrogen, and phosphorus equivalent ratios, were 1.38, 1.59, and 1.62, respectively, which increased the net profit of wheat/chickpea by 55% compared to wheat/soybean, suggesting that intercropping systems require fewer anthropogenic inputs to produce higher crop yields than sole systems. Our results contribute to understanding the effects of crop type and temporal synchronization of intercrop species for maximizing the land productivity of cereal/legume intercropping systems in arid irrigated regions.