Grain yield, water-land productivity and economic profit responses to row configuration in maize-soybean strip intercropping systems under drip fertigation in arid northwest China

Intercropping has great potential for alleviating arable land competition, improving land output and promoting sustainable agricultural development. However, the applicability of maize-soybean strip intercropping under drip fertigation in arid northwest China remains unclear, especially under various row configurations. A two-season (2022 and 2023) field experiment was performed in the Hexi Region of northwest China to investigate the responses of plant growth, yield performance, water-land productivity and economic profit of drip-fertigated maize-soybean strip intercropping systems to eight row configurations. The results showed that intercropping significantly reduced aboveground biomass accumulation of maize and soybean by 18.77% and 47.81% on average compared to monocropping, respectively. Intercropping significantly decreased the 100-grain weight, ear length and ear width of maize, and reduced the 100-grain weight and pod number of soybean, resulting in reduced grain yields of intercropped maize and soybean (by 13.08% and 48.73%, respectively), but two rows of maize alternating with four rows of soybean (M2S4), three rows of maize alternating with four rows of soybean (M3S4), four rows of maize in wide and narrow rows alternating with four rows of soybean (M4S4-MN), and four rows of maize in wide and narrow rows alternating with six rows of soybean (M4S6-MN) produced greater population grain yield compared to monocropping. Among all intercropping systems, the largest water-land productivity and economic profit occurred in M2S4 (1.61 in 2022 and 1.42 in 2023 for land equivalent ratio; 29.23 kg ha−1 mm−1 in 2022 and 28.22 kg ha−1 mm−1 in 2023 for water productivity; 23,965 CNY ha−1 in 2022 and 23,059 CNY ha−1 in 2023 for economic profit), followed by M4S4-MN (1.53 in 2022 and 1.36 in 2023 for land equivalent ratio; 27.11 kg ha−1 mm−1 in 2022 and 26.58 kg ha−1 mm−1 in 2023 for water productivity; 22,327 CNY ha−1 in 2022 and 22,224 CNY ha−1 in 2023 for economic profit). The M2S4 is thus the optimal row configuration for drip-fertigated maize-soybean strip intercropping systems in terms of grain yield, economic profit and land productivity, while the M4S4-MN is recommended by further considering the efficiency of mechanized sowing and harvesting.