Increased Overyielding Probability and Yield Stability from a 5-Year Cotton-Based Intercropping

In the context of global climate change, it is crucial to design cropping systems with high and stable crop yields. Recent studies have shown that intercropping systems can improve productivity and enhance yield stability. However, the results remain much uncertainty due to variations in cropping system and environment along with other factors. Here, a 5-year study was conducted to investigate the overyielding, temporal yield stability, and underlying mechanisms in cotton-based intercrops (i.e., garlic/cotton, wheat/cotton, and peanut/cotton). Overall, cotton-based intercrops outperformed the monocultures by 17.6% on average, with the overyielding probabilities of 71%. We show for the first time that cotton-based intercropping systems significantly reduced the risk of yield failure (yields below the 10th percentile) by 12.4% and increased the upside potential of yield (yields above the 90th percentile) by 9.3% relative to monoculture systems. Intercropping systems also increased temporal yield stability by 36.8% compared with monocultures. However, overyielding and yield stability varied between the three intercropping combinations, with garlic/cotton and wheat/cotton intercropping showing the greatest improvements. The temporal stability of crop yield slightly increased, while the probabilities of years with major declines in crop yield greatly decreased. Enhanced yield gain from cotton-based intercropping systems compared with monoculture was strongly and positively correlated with the complementarity effect, which suggested that niche partitioning and facilitative effects of two components were main mechanisms driving yield gain. In addition, temporal yield stability was positively correlated with yield and compensatory dynamics. Thus, diversified cropping systems through garlic or wheat/cotton intercropping can be used as a promising way to move toward more sustainable agriculture while maintaining a sufficient level of crop production.