Objective In response to the severe decline in soil quality in arid orchards of southern Xinjiang, this study investigated the effects of incorporating green manures from different botanical families on orchard soil physical properties, aiming to provide a scientific basis for optimizing regional green manure cultivation.

Methods Green manures from Leguminosae (alfalfa and hairy vetch), Poaceae (oat), and Brassicaceae (rape) were selected, with clean tillage as the control. A field experiment was conducted in a pear orchard in southern Xinjiang to measure the changes in soil bulk density, porosity, water content, and compactness before and after green manure incorporation. One-way ANOVA was used to test the significance of differences among treatments.

Results Green manure incorporation significantly reduced soil bulk density in the surface layer (0 − 10 cm), with a maximum reduction of 15% (decreasing to 1.22 g/cm³), and increased porosity (by up to 10%) and water content (by 20% in the surface layer). Leguminous green manures significantly reduced soil bulk density (to 1.22 g/cm³) and increased porosity (to 58.5%), while Poaceae and Brassicaceae green manures exhibited stronger water retention effects, with surface water content reaching 14.8% and subsurface water content significantly increasing to 15.7%. Soil compactness decreased significantly in the surface layer (by 29%, to 320 kPa), but no significant changes were observed in the deeper layers (P>0.05).

Conclusion Leguminous green manures are more suitable for improving soil structure, while Poaceae and Brassicaceae green manures are more effective in enhancing soil water use efficiency. In practice, different families of green manures should be rationally combined according to the specific needs of soil improvement, in order to achieve comprehensive enhancement of soil quality.