Effects of Orchard Grass on Soil Fertility and Nutritional Status of Fruit Trees in Korla Fragrant Pear Orchard

Grass cultivation is widely used as an effective soil management method in pear orchards. A Korla fragrant pear orchard with clean cultivation (CK) and natural grass planting for 1, 2, 3, 4, and 5 years was examined in this study. We analyzed the differences in soil fertility and shoot and leaf nutrient content under different grassing years. Compared with the clean cultivation, grass cultivation reduced the soil fertility and nutrient content of shoots and leaves at the early stage of natural grass planting (1–2 years). With the increase in grassing years, the overall level of the nutrient content of soil, shoots, and leaves gradually increased; the shallower the soil layer, the more significant the effect. Furthermore, grass cultivation significantly increased the contents of soil organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen, available phosphorus, and available potassium. The nutrient contents of shoots and leaves were also significantly increased after grass cultivation. The contents of total nitrogen, total phosphorus, and total potassium in shoots were significantly increased by 7.32%, 154.84%, and 219.29% in 5, 4, and 5 years, respectively, and their contents were also increased by 69.57%, 22.86%, and 26.45% in leaves. The correlation analysis showed that there was a significant or extremely significant positive correlation among the shoots, leaves, and soil nutrient contents. In conclusion, continuous grass cultivation significantly improved the soil quality, health status, and nutritional status, and effectively solved the problem of harm to the pear orchard caused by long-term clean cultivation. This study will provide the scientific basis for the construction of a reasonable orchard soil management mode.