Effects of walnut/ compound planting on growth, fruit yield, quality of and soil properties.

Walnut and are important arbor and shrub fruit trees cultivated in the southwest mountainous area of China. Furthermore, those two species are compound cultivated in this area. In this study, we investigated the growth, yield, fruit quality, photosynthesis, and soil fertility of in a 7-year typical 'Qianhe 7'/ 'Guinong 5' compound planting pattern in Guizhou. The results showed that compared with the monoculture, photosynthetic pigment content and photosynthetic rate of leaves were significantly lower in the compound plantation. The growth and yield of decreased significantly, with a 77.7% reduction of yield. Fruit quality of was improved. The content of ascorbic acid (Vc), total phenol, carbohydrate, K, Ca, Mg, Fe, Mn, Zn, and other substances increased significantly. Fruit Vc and Mn content increased by 34.1% and 64.1%, respectively. The contents of total N, available N and K in the soil increased by 45.8%, 34.8% and 67.8%, respectively. The abundance of soil microorganisms and functional bacteria increased significantly, with the increase of bacteria and fungi being more than 36.0%. The increase of potassium bacteria and nitrogen fixing bacteria was 71.3% and 124.8%, respectively. However, the contents of organic matter, carbon-nitrogen ratio, total P, total K, available mineral nutrient (P, Ca, Mg, Fe, Mn, Cu, Zn) contents decreased. While the activities of soil urease and catalase were increased, the activities of other soil enzymes (sucrase, cellulase, protease, phosphatase) were significantly reduced. In summary, with continuous growth of walnuts in the walnut/ compound plantation, there was obvious shade and soil fertility competition for , which affected its yield, but had a improvement effect on fruit quality.