Effects of tobacco intercropping on the Spatial relationship between natural enemies and pests and economic efficiency.

Intercropping is widely recognized for its suppression of crop pests and enhancement of economic benefits. However, there is a scarcity of studies that quantify the mechanisms of community ecology underlying these effects. To address this, we conducted a study on the intercropping of tobacco with Amorphophallus konjac, soybean, and sweet potato. The relationship between the numbers of natural enemies and pests under different cropping systems was analyzed using linear regression and partial least squares regression. The spatial relationships between natural enemies and pests were analyzed using Levins' spatial niche overlap index and generalized additive models. The economic benefits of different cropping methods were evaluated based on crop yield, the proportion of high-quality products, average price, and land use equivalency ratio. Results showed that the numerical relationships between natural enemies and pests were not significantly correlated with whether intercropping was practiced or the type of intercropped crop. Significant differences in the spatial relationships between natural enemies and pests were observed among different crops, as determined by generalized additive mixed models (P < 0.05). The proportion of high-quality products and average price were more strongly influenced by the spatial relationships between natural enemies and pests than by their numerical relationships. Based on the results, it is recommended that intercropping tobacco with sweet potatoes can bring greater positive economic benefits.