Effects of grass growing on soil fertility and productivity of orchards in China: A metaanalysis.

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.果园生草是维持土壤基础肥力、改善土壤生态环境、推动果树产业可持续发展的有效措施之一。但是,有关生草对果园土壤养分含量的定量改变,及其对果园果实产量和品质的提升机制并不清楚。本研究采用Meta分析,共搜集了1990—2020年间发表的62篇文献,定量分析土层深度、生草种植年限和生草植物种类对果园土壤理化性质和果实产量及品质的影响,探究果园生草对中国果园可持续生产的影响。结果表明: 1990—2020年间,与不生草果园相比,果园生草土壤有机质、碱解氮、速效磷含量可分别提高18%、11%、27%,土壤容重降低20%;当气温低于10 ℃时,果园生草可使土壤温度增加23%;当气温高于10 ℃时,果园生草可使土壤温度平均降低8%左右。与一年生草相比,果园连续多年生草,无论是自然生草,还是人工生草,都显著提升了果园土壤质量、产量和果实品质(如可溶性固形物)。因此,果园长期生草对中国果园可持续生产具有深远意义。.