Drought risk assessment for maize/peanut intercropping based on crop model and SPEI

Context

Drought occurs frequently under climate change and is considered a huge threat especially for the rain-fed agricultural region. Intercropping systems are promoted as an adaptation to mitigate drought stress due to the interspecific complementarity of intercropped species and improved water use efficiency.

Objective

The aim of this study was to select a drought risk assessment model for maize/peanut strip intercropping to quantitatively evaluate whether intercropping can mitigate drought risk compared to sole stands, using the daily Standardized Precipitation Evapotranspiration Index (SPEI) for analysis.

Methods

The Agricultural Production Systems Simulator (APSIM) is widely used to assess the potential impacts of climate change on crop yield. In this study, we employed the APSIM model, integrated with a light interception model for strip intercrops, to quantify yield losses caused by crop droughts in four maize/peanut strip intercropping treatments from 1951 to 2020. Additionally, we developed physical vulnerability curves and the corresponding drought hazard indices.

Results and conclusions

Based on the drought risk assessment index, intercropping decreased drought risk by 2.16 % compared with sole stands across all testing row configurations. In this study, we found that maize/peanut strip intercropping reduced drought risk by 5.7 % over the past 35 years, outperforming the previous 35 years. We concluded that the intercropping could be a risk management strategy in rain-fed agriculture, and among the four tested intercropping systems, including 2 rows of maize and 2 rows of peanut, 4 rows of maize and 4 rows of peanut, 6 rows of maize and 6 rows of peanut, and 8 rows of maize and 8 rows of peanut, strip intercropping with 2 rows of maize and 2 rows of peanut was the best.

Significance

Our long-term simulations confirmed that intercropping could reduce drought risk in rain-fed agriculture under global climate change. Overall, this study introduces drought risk quantification methods in ecosystem biodiversity. However, further field experiments are still needed to explore the impact of resource competition on intercropping system performance. Additional data from other locations will enhance the spatial representation in future research. Future research should also combine crop physiology and ecological theories to study intercropping drought resistance from a crop mechanism perspective.