枯落物敷盖对红壤坡地土壤水分特性的影响

Effects of Litter Mulch on Soil Water Properties in Red Soil Sloping-land

为探明红壤坡地枯落物敷盖的保水作用及其机理,在江西省北部德安县第四纪红黏土母质发育的红壤坡地开展定位试验,以裸露坡地为对照,研究枯落物敷盖措施实施15年后对0—60cm土层土壤的持水性、供水性和水分有效性的影响。结果表明：赣北红壤坡地的土壤水分持水能力低,供水能力弱,有效水含量少,仅为9.0%-11.1%;枯落物敷盖处理的红壤坡地上层（0—30cm）土壤持水能力高于裸露坡地;低吸力范围（〈100kPa）枯落物敷盖处理的下层（30—60cm）土壤供水能力高于裸露坡地。枯落物敷盖能够有效提高红壤坡地土壤（尤其是上层土壤）持水能力,增强上层土壤在相对湿润状况下的供水性能,而对土壤水分有效性影响相对较弱。该研究可为优化地表敷盖措施、增加和保持土壤水资源以及合理开发利用南方红壤坡地提供参考。

To explore the effect of litter mulch on preserving soil water and its mechanism in red soil sloping-land,in situ experiments were conducted in sloping-land of red soil derived from Quaternary red clay in De’an County in northern Jiangxi Province,the effects on soil water retention capacity,soil water supplying capability and soil water availability of the 0—60cm soil layer were studied after the litter mulching measure had been implemented for 15 years,with the bared slope being used as the control.The results showed that soil water retention capacity of red soil in northern Jiangxi Province was low,water supplying capability was weak,and soil water availability was low,i.e.from 9.0% to 11.1%.The water retention capacity of the upper layer of the soil（i.e.the soil within 0—30cm depth）on the red soil slope with little mulch was higher than that of the bared slope.The water supplying capability of the lower layer of the soil（i.e.the soil within the 30—60cm depth）of the red soil slope with litter mulch was higher than that of the bared slope when the soil water suction was less than 100 kPa.Litter mulch effectively increased the soil water retention capacity of the red soil,especially for the upper layer,and also enhanced the water supplying capability of the upper layer of the soil under relatively wet conditions,but had relatively weak effects on soil moisture availability.The results of this study can provide guidelines for the optimization of the surface mulching measures of sloping cropland,increasing and maintaining soil water resources,and reasonable exploitation and utilization of red soil slopes in southern China.