Abstract: Planting grasses in orchards is important to maintain soil basic fertility, improve the soil ecological environment, and promote sustainable growth of fruit. However, the quantitative effects of grasses on nutrient content of orchard soil in China is unclear, as well as the mechanisms associated with higher fruit yield and quality in orchards. This meta-analysis included 62 literature published between 1990 and 2020 to quantify effects of soil depth, planting years of raw grasses, and raw grasses to the physical and chemical properties and fruit yield and quality of orchards, as well as to explore the impacts of grasses on the sustainable production of Chinese orchards. Between 1990 and 2020, compared with the non-grass orchards, the content of soil organic matter, alkali nitrogen and available phosphorus in orchard with grasses increased by 18%, 11%, and 27% respectively, and the soil bulk density was reduced by 20%. Orchard grass increased soil temperature by 23% when the temperature was below 10 ℃, and reduced soil temperature by about 8% when the temperature was above 10 ℃. Compared with annual grasses, perennial grasses (natural or artificial) significantly improved soil properties, fruit yield and quality. These findings indicated that long-term grass planting in orchards had far-reaching significance on sustainable production.

Key words: planting grass in orchard, soil physical and chemical properties, yield, quality, ecological benefit, meta-analysis.