Surface mulching effects on soil properties, citrus leaf nutrient and fruit quality in red soil region orchards of Guangxi

Guangxi covers the largest citrus planting area in China, and orange orchard is the most typical orchard ecosystem in Guangxi.Weed management is the priority in citrus orchards management.However, few is reported concerning the effects of different surface mulching on soil nutrient supply, citrus nutritional status and fruit quality.In this study, we applied grass-proof cloth cover (GPC) and natural grass mowing (NGM) treatments with conventional herbicide spraying (bare ground) as the control(CK) in the citrus orchard of typical red soil area to analyze the characteristics of soil physical and chemical properties, citrus leaf nutrition and citrus quality under different surface mulching.The results showed that GPC treatment significantly increased the pH value of topsoil, but decreased organic carbon by 14.2%; NGM treatment significantly reduced the bulk density of surface soil, but significantly increased soil pH by 9.8%(P < 0.05).GPC treatment increased the contents of available K, available Ca and available Zn in topsoil and promoted nutrition levels of N, K, Mg and Zn in citrus leaves; NGM treatment significantly improved the supply of soil alkali-hydro N, available K, available Ca, available Mg and available Zn, and increased the contents of N, P, K, Ca, Mg, Zn and B in citrus leaves in autumn and winter.GPC treatment significantly reduced the titratable acid content of citrus, while NGM treatment significantly increased the total sugar content of citrus.Mulching methods significantly increased the sugar acid ratios of citrus by 12.8% and 20.1% compared with CK(P < 0.05), respectively.Compared with CK, GPC treatment reduced vitamin C(Vc)content by 28.8%, while NGM treatment increased Vc content by 5.82%.The comprehensive analysis showed that natural grass mowing would be a better weed management option in Guangxi citrus orchard.