As global climate change intensifies, extreme weather events and natural disasters, such as droughts, are becoming more frequent and severe, posing significant challenges to agricultural production and farmer livelihoods (Lou et al., 2024). To ensure sustainable and stable agricultural systems, farming practices that can adapt to these adverse conditions are essential (Lou et al., 2024; Chimi et al., 2024). The relationship between biodiversity and ecosystem stability has been extensively studied following the development of the diversity-stability hypothesis (Odum, 1953; MacArthur, 1955). Intercropping—a practice where two or more crop species are grown together for all or part of their growing season—has gained attention as a strategy for increasing biodiversity in agricultural systems (Feng et al., 2021; Pelech et al., 2023). By diversifying agricultural systems, intercropping can enhance crop production and improve resilience to stresses, such as drought, through optimizing resource use and system adaptability (Renwick et al., 2020; Nelson et al., 2022).

To maximize the benefits of intercropping, selecting appropriate crops and designing suitable intercropping configurations are essential (Brooker et al., 2015). Additionally, crop characteristics such as canopy structure (Chai et al., 2014), root system depth (shallow or deep) (Xia et al., 2013), and growth stages (Zhang et al., 2017) must also be considered. Recent research aimed at improving drought resistance and yield stability in intercropping systems has primarily focused on nutrient and water use (Feng et al., 2024; Zhang et al., 2024b; Ma et al., 2019). For instance, in maize/soybean intercropping systems, the root length density of both maize and soybean is higher than in monocultures, which enhances water uptake and improves drought resistance (Ren et al., 2017). However, there has been less focus on the impact of aboveground configurations on the water use efficiency of intercropping systems.

Rainfall is intercepted by the canopy and is then distributed as stemflow and throughfall into the soil (Nanko et al., 2016). Stemflow refers to the volume of water that flows down the plant stem to the roots after being captured by the plant canopy (Lamm and Manges, 2000). Throughfall, on the other hand, is the portion of rainfall that reaches the soil through gaps or complex structures in the canopy, representing a significant form of rainfall under crop canopies (Zhu et al., 2021; Guo et al., 2023). Thus, appropriately structured canopies can ensure drought resistance, stable yields, and efficient resource utilization (Yang et al., 2017; Nelson et al., 2018). The canopy, composed of stems, branches, and leaves, acts as the interface between the plant and its environment (Franco et al., 2018). Generally, in response to drought stress, crops modify their plant height, leaf area, number of branches or tillers, number of reproductive organs, growth period length, stomatal closure, direction of photosynthetic assimilate transport, enzyme composition, and genetic structure—collectively known as “growth redundancy” (Gao et al., 2020; Ye et al., 2020; Nehe et al., 2021). In intercropping systems, interactions between species can affect canopy development. For instance, intercropping maize and peanuts significantly alters the plant canopy structure compared to monocultures. Peanuts have abundant branches and leaves, shorter plant height, and better surface coverage (Tahir et al., 2016). This structure reduces the diffusion resistance of the boundary layer and minimizes soil moisture evaporation, facilitates airflow, and significantly improves the overall transpiration efficiency of both crops. While the relationship between canopy structure and drought resistance is better understood in monoculture systems, crops in intercropping systems exhibit similar adjustments.

A semi-arid region in northeastern China lies at the intersection of the Mongolian Plateau and Northeast Plain. This area receives annual precipitation ranging from 350 to 500 mm, though this amount fluctuates significantly from year to year, leading to low and variable crop yields (Lu and Shi, 2024). The main crops in this region are maize and peanuts (Feng et al., 2021). Maize, an essential food crop, has high water-use efficiency, but its tall stature and high rates of transpiration and evaporation result in substantial water demands. This increases the risk of poor harvests in the semi-arid region (Zhang et al., 2024a). In contrast, peanuts require less water than maize, and are more drought tolerant (Feng et al., 2021). Therefore, intercropping maize and peanut helps optimize the limited water supply in drylands and improve agricultural resistance to drought. Intercropping can also block and reduce deep leakage and surface runoff of rainwater and irrigation water in maize and peanut canopy layers, improve usage of rainfall, and enhance soil water storage capacity, with significant economic benefits (Feng et al., 2016; Hamd-Alla et al., 2023). Additionally, Intercropping maize and peanut can also stagger critical periods of crop water demand and reduce interspecies competition, which is important for efficient water use in intercropping systems (Chauhan et al., 2015). However, little is known about how combining maize and peanut crops affects the passage of water flow into soils.

We investigated the impact of maize canopy structure and strip width on water flow in intercropped maize and peanut systems. Our objective was to evaluate whether intercropping could improve both agricultural stability and productivity in semi-arid, drought-prone regions, while also identifying more suitable planting patterns for these areas.

Our results indicate that narrower strip widths can increase maize leaf area, regardless of whether the growing season is in a wet or dry year. This suggests that light and space, rather than water availability, are the primary limiting factors for maize leaf extension in the maize-peanut intercropping system studied. Previous research has shown that intercropping with varying strip widths and canopy architectures creates spatial niche differentiation, alters light distribution, and affects yield (Wang et al., 2021; Yang et al., 2024). This suggests that the competitive relationship between intercrops in a specific strip intercropping system is regulated by width configuration (Abakumova et al., 2016). In the narrower strip width intercropping system, as shown in Figure 1, maize plants were less constrained by each other due to the presence of more edge rows. Fu et al. (2023) proposed that high N availability can enhance maize leaf extension in maize-legume intercropping systems. Given that strip width in maize-peanut intercropping has a significant impact on soil N availability and plant N uptake (Zhang et al., 2024c), this may influence maize leaf area. In contrast to leaf area, plant height increased with narrower strip widths during normal and dry years but was not affected by strip width during the wet year. This indicates that water availability is the primary factor controlling plant height in this climate region. Similarly, a study in a high rainfall area by Zou et al. (2024) found that maize-peanut intercropping had no effect on maize height.

Through this experiment, it was found that intercropping can affect the allocation of rainfall between intercrops. Maize-peanut intercropping significantly increased stemflow and throughfall in maize rows, while it reduced throughfall in peanut rows. Maize obtained more rainfall than peanut due to its greater height and canopy, which overshadows the peanut rows. Due to this reason, in most cases, maize received more water than what was provided by rainfall in the maize-peanut intercropping system, with the excess water being taken from the peanut strips. Similar results have been observed in maize-soybean intercropping systems(Wang et al., 2024). We found a positive correlation between maize stemflow and both maize leaf area and plant height, whereas a negative relationship existed between maize and peanut throughfall and maize leaf area and plant height. These findings indicate that more rainfall is allocated to maize rows as maize leaf area and height increase, leading to higher water use efficiency (WUE) in maize and lower WUE in peanuts. This study was conducted in a semi-arid region where water availability is a key limiting factor for crop growth. Maize, being a high water-consuming crop, consistently shows increased WUE with higher water availability (Zhao et al., 2024). Our results support this, as maize WUE increased with narrower strip widths and higher rainfall allocation. However, for peanuts, due to their lower water consumption, no significant difference in WUE was observed between M4P4 and M8P8, regardless of whether it was a wet or dry year, even when rainfall allocation decreased.

In general, the water consumption of sole-cropped maize increases with plant height and leaf area. In intercropping systems, maize can not only capture more rainfall through its canopy but also extract water from peanut strips in the soil during drought periods. In this study, the water consumption of intercropped maize was estimated based on changes in soil moisture content within the intercropping strip. Therefore, it does not represent the actual water consumption of the maize itself. This explains why intercropped maize in this study exhibited large plant height and leaf area but relatively low water consumption. However, relevant research is highly valuable for assessing the water use efficiency of maize-peanut intercropping systems. Mao et al. (2012) provided a detailed explanation of the methods for measuring WU, WUE, and WER (Equations 1–5) in intercropping systems, and their findings are consistent with the results of this study.

Comparing the different strip width treatments over the three years, we found that the M4P4 treatment exhibited the highest system WUE and crop productivity, as indicated by WER and LER. This suggests a balanced resource allocation between the maize and peanut strips. In the M4P4 treatment, approximately 27% of the rainfall from the peanut strip was allocated to the maize strip, resulting in a significant increase in maize yield with minimal impact on peanut yield (Table 1). Additionally, the relatively high WER and LER can be attributed to the edge effect. It is generally understood that the yield-enhancing effect of intercropping is largely due to the edge effect (Wang et al., 2017). Historically, positive edge effects in intercropping systems were thought to arise from differences in how the canopy influenced light interception and distribution (Wang et al., 2020; Zhang et al., 2020). Our research also identified an edge effect on rainfall redistribution within the intercropping system (Figure 8). Compared to M2P2 treatment, maize in the edge row of M4P4 received less water, while peanut rows received more. During drought periods, soil water could flow from the peanut rows to the maize rows, maintaining a steady water supply for maize. However, the long distance between the rows, such as M8P8, limited the movement of water from peanut to maize, while also increasing the potential for evaporation.

This study highlights the significant effects of strip width in maize-peanut intercropping systems on both crop productivity and water use efficiency (WUE). The M4P4 treatment demonstrated the highest system WUE and crop productivity, as evidenced by the higher values of the Land Equivalent Ratio (LER) and Water Equivalent Ratio (WER). The allocation of rainfall from the peanut strips to maize in the M4P4 treatment contributed to a notable increase in maize yield with minimal impact on peanut yield. This result suggests that intercropping with appropriate strip widths can optimize water redistribution, especially during drought periods, benefiting maize while maintaining peanut productivity. Furthermore, the edge effect played a significant role in enhancing yield and water use efficiency in the intercropping system. The maize rows at the edges benefited from the allocation of water, particularly during dry periods, while the peanut rows showed reduced throughfall, further supporting the positive effects of intercropping on water management. However, the long distance between rows in the M4P4 treatment also introduced some limitations, such as increased evaporation potential and restricted water movement between rows. These findings underscore the importance of strip width and edge effects in designing intercropping systems that maximize resource use and enhance crop productivity, particularly in semi-arid regions where water availability is a critical limiting factor.

Overall, the results of this study provide valuable insights for optimizing strip width configurations in intercropping systems. They demonstrate that careful management of spatial arrangements can improve both crop productivity and water use efficiency, with potential applications in sustainable agricultural practices.