Maize/soybean strip intercropping enhances crop yield in rain-fed agriculture under the warming climate: a modeling approach

Abstract

Rising temperatures and more frequent droughts caused by global climate change reduce yields and increase climate risk, especially in rain-fed agriculture. Together with scarce land and water resources, this poses a serious threat to food security. Field experiments have shown that relay intercropping systems under irrigated conditions can improve productivity. However, little is known whether these improvements could also be obtained with simultaneous intercropping in rain-fed agriculture under water-limited conditions. To investigate this question, we analyzed a maize/soybean simultaneous intercropping system, using a modeling approach. A light interception model for strip intercrops was implemented into the APSIM classic model for simulating crop growth and yield in strip-intercropped maize and soybean and then calibrated and validated using field experiments conducted from 2017 to 2019 at 4 sites in Northeast China. We then ran a simulation using climatic data (1961–2020) from these sites. Model validation showed good agreements between observations and simulations. The results obtained from our simulation over the period from 1961 to 2020 showed that intercropping was predicted to increase total yields by 41.3% and subsequently enhanced total economic revenue by 23.8% compared to sole systems. It also reduced yield gap of maize by 33%, soybean by 56%, and the system by 45%. Attainable land equivalent ratio (LER) under rain-fed conditions was 1.27 over 60 years across the 4 sites, with a relative yield gain of maize of 0.35 and a relative yield loss of soybean of 0.08. Attainable LER was higher than potential LER. Yields and LER were significantly higher between 1991 and 2020, indicating a potential increase in land productivity with intercropping under a warming climate. Our results thus suggest that simultaneous intercropping offers great opportunities for yield enhancement in rain-fed agriculture under global climate change.