覆盖和耕作对黄土高原冬小麦土壤入渗特性的影响

用人工模拟降雨器对黄土高原冬小麦收获后6个耕作措施:不翻耕(NT),不翻耕 覆盖(NTC),浅翻耕(LT),浅翻耕 覆盖(LTC),深翻耕(DT),深翻耕 覆盖(DTC)处理下土壤的入渗进行了研究,测定了土壤表面结皮、粗糙度等指标因子。结果表明,在模拟降雨强度为66 mm/h的条件下,覆盖处理的稳定入渗率>60 mm/h,降雨开始的40 m in内,平均入渗量>93%;深翻耕(DT)的稳定入渗率(26.4 mm/h)是浅翻耕(LT)(13.0 mm/h)的2倍,是不翻耕(NT)(6.4 mm/h)的4.1倍,降雨历时20m in时,深翻耕(DT)和浅翻耕(LT)分别比不翻耕处理(NT)减少径流28%和7%,40 m in时,浅翻耕(LT)和不翻耕(NT)处理径流量相当,深翻耕(DT)比这两个处理减少径流30%左右,土壤翻耕后在前期能提高土壤的入渗率,表现出经长年耕作后土壤退化的强烈特征,是“耕地越深,入渗越快”观念的根源;地表结皮是影响降雨入渗的主要因素,覆盖等保护性耕作更有利于土壤入渗。

Impact of Different Tillage Method on Infiltration Character to Winter Wheat in the Loess Plateau

Infiltration characteristics of a Heilu soil were determined using simulated rainfall(rainfall intensity is 66 mm/h) under six tillage methods: no-till(NT);no-till with stubble retention(NTC);till with shallow depth(LT,10cm);till with shallow depth with stubble retention(LTC);till with deep depth(DT,20 cm);Till with deep depth with stubble retention(DTC).Soil surface cover,roughness and crust development was measured.The results showed that cumulative rainfall infiltrated to soil was over 93% at the beginning of rainfall run 40 min under stubble retention,the last or steady infiltration rate >60 mm/h.Tillage increased rainfall infiltration at first rainfall run;the last or steady infiltration rate under DT treatment(26.4 mm/h) is 2 times than under LT treatment(12.96 mm/h),while 4 times than under NT treatment(6.35 mm/h).When rainfall ran 20 min,DT treatment increased infiltration by 21% and 28%,compared with under LT and NT treatment,when at 40 min,by 31% and 33%.The results can provide some parameters for infiltration model and benefit to farming systems.