Abstract: Aims In order to understand the interspecies competition strategy of the new fruit - bean agroforestry system and find a planting pattern that balances ecological and economic benefits, the Malus pumila 'Saiwaihong' - Glycine max agroforestry system (MS) was set up. Methods Through the study on root length density (RLD), specific root length (SRL), root vertical center, competitiveness index and interspecific relative competitiveness of the Malus pumila 'Saiwaihong' - Glycine max agroforestry system, the interspecific competition strategy was revealed. Important findings The results showed that the RLD of intercropping fruit trees and soybean was lower than that of monoculture, and the trend of SRL was opposite. Soybean roots were mainly distributed at 0-20 cm soil depth and 150-200 cm away from the tree, and decreased with the increase of soil depth and the decrease of distance from the tree. The root system of intercropping malus mainly distributed in the soil depth of 20-40 cm. With the growth period, the vertical center of fine roots moved downward. In the Malus pumila 'Saiwaihong' - Glycine max agroforestry system, each plant adopted different interspecific competition strategies. Fine roots of soybean became a strong competitor in the surface soil of the Malus pumila 'Saiwaihong' - Glycine max agroforestry system by increasing SRL and reducing root weight. Intercropping Malus could reduce niche overlap and resource competition with intercropping soybean by moving down the root distribution center, lengthening root length and increasing root weight. The overall interspecific relative competitiveness of malus was stronger than that of soybean, but the competitiveness index of soybean was still stronger than that of malus in the topsoil. The yield of intercropping soybean was 34.12% lower than that of monoculture. There was no significant difference in the yield of malus. The land equivalent ratio (LER) and income equivalent ratio (IER) of the agroforestry system were greater than 1. The results showed that the underground competition of Malus pumila 'Saiwaihong' - Glycine max agroforestry system was weak, and it had good intercropping advantages which were suitable for planting in Xinjiang province. The results of this study can provide a reference for the selection of planting patterns of agroforestry systems in arid and semi-arid areas.

Key words: fruit + soybean agroforestry system, root distribution, interspecific competition, Malus pumila 'Saiwaihong'