Reducing interspecific competition to improve system productivity in apple-crop intercropping systems in arid regions

Abstract Aims The aims of this study were (1) to assess which intercropping pattern is feasible in enhancing soil moisture and promoting crop root growthand (2) to integrate crop root data to assess which intercropping pattern can reduce interspecific competition and thus increase system productivity. The optimal cropping pattern was determined by calculating the land equivalent ratio (LER). MethodsIn this study, we designed two intercropping patterns (intercropped apple-soybean [IAS] and intercropped apple-alfalfa [IAA]) and analysed the effects of these intercropping patterns on soil moisture, crop roots, interspecific relationships and yields to determine the most suitable cropping pattern for local promotion. Results At 50–200 cm, IAS and IAA increased soil moisture by 43.99% and 46.52%, respectively, compared to monocropped apple (M). However, due to competition, intercropped apple, intercropped soybean and intercropped alfalfa all showed a decreasing trend in the root system, by 6.04%, 30.8% and 13.9%, respectively. Both soybean and alfalfa were strongly competitive with apple at 0–20 cm soil depth, while apple showed strong competitiveness with soybean and alfalfa at 20–40 cm soil depth. The LER of IAS was higher than that of IAA, and in a comprehensive analysis, IAS was more suitable for local promotion than IAA. Conclusions These results showed that IAS has less interspecific competition than IAA and that the system is more productive and more suitable for local extension.