绿洲农田休闲期留茬免耕条件下冬灌对土壤容重与孔隙的影响OA

To evaluate the effects of winter irrigation on soil physical properties in arid oasis irrigation districts under residue-retained no-tillage during the fallow period,a two-year field observation was conducted in Minqin(lower Shiyang River Basin)during 2018-2019 and 2019-2020,with separate treatments in wheat and maize fields.Treatments compared no-tillage with and without winter irrigation,and soil bulk density as well as capillary and non-capillary porosity were monitored along the 0～100 cm soil profile.Results showed that soil bulk density generally increased in the 20～60 cm layer for wheat fields and in the 0～60 cm layer for maize fields during the fallow period,while changes in the 60～80 cm layer were not pronounced;winter irrigation did not significantly alter bulk-density dynamics.Capillary porosity generally decreased without winter irrigation;winter irrigation did not change the overall depth-wise direction of variation but reduced the magnitude of capillary-porosity deterioration,suggesting a buffering effect against freeze-thaw-induced pore degradation.Non-capillary porosity increased in shallow layers but decreased in deeper layers,with winter irrigation dampening the overall amplitude of change.These plot-scale findings provide evidence for optimizing the"moisture-freeze-thaw-pore structure"pathway of winter irrigation during fallow management in oasis irrigation areas,and highlight the need for replicated multi-site trials to further quantify the optimal winter irrigation quota and timing.