黔西喀斯特区秸秆覆盖对坡耕地产流产沙特征的响应

Effects of Straw Mulching on Runoff and Sediment Characteristics of Sloping Farmland in the Karst Area of Western Guizhou

基于2018-2019年野外径流小区定位观测资料,以玉米单作无秸秆覆盖处理(M0)为对照,探索了玉米单作处理和不同秸秆覆盖量(M1~M5,1111,2222,3889,5556,6944 kg/hm^2)对贵州省黔西喀斯特区坡耕地产流产沙特征的影响。结果表明:(1)不同降雨等级下,秸秆覆盖具有较好的水土保持效果,并随覆盖量的增加,产流、产沙总量逐渐减少,但M4与M5处理之间无显著差异(p>0.05);(2)玉米苗期—拔节期各处理产流和产沙量大于后2个阶段,并且各阶段各覆盖处理产流产沙均低于对照;(3)秸秆覆盖对地表产流产沙影响显著,与对照相比,年均径流深减少21.85%~50.46%,土壤侵蚀模数减少50.10%~85.87%;(4)随着秸秆覆盖量的增加,各处理产流、产沙呈下降趋势,但当秸秆覆盖量超过5556 kg/hm^2后,继续增加秸秆至6944 kg/hm^2时,水土保持效果变化不明显。秸秆覆盖是控制喀斯特地区坡耕地水土流失的有效途径,6000 kg/hm^2左右的覆盖量即可起到较好的水土保持效果。

Based on the location observation data of the wild outflow plots from 2018 to 2019,taking the corn monoculture treatment without straw mulch(M0)as the control,this study was aimed to explore the effects of maize monocropping treatment and different straw coverage(M1~M5,1111,2222,3889,5556,6944 kg/hm^2)on runoff and sediment yield characteristics of sloping farmland in the karst area of Guizhou Province.The results showed that:(1)Under different rainfall levels,straw mulching had better soil and water conservation effect,and with the increase of mulching amount,the total runoff and sediment yield decreased gradually,but there was no significant difference between M4 and M5 treatments(p>0.05);(2)The runoff and sediment yield of each treatment from seedling stage to jointing stage were greater than those of the latter two stages,and the runoff and sediment yield of each mulching treatment in each stage were lower than that of the control;(3)Compared with the control,the annual average runoff depth decreased by 21.85%~50.46%,and soil erosion modulus decreased by 50.10%~85.87%;(4)As the amount of straw mulching and the amount of straw buried in the soil increased,the runoff and sand production of each treatment showed a downward trend.However,when the straw mulching amount exceeded 5556 kg/hm^2 and continued to increase to 6944 kg/hm^2,the soil and water conservation did not change significantly.Straw mulching was an effective way to control soil and water loss of sloping farmland in karst area,and the coverage amount of about 6000 kg/hm^2 was recommended in the soil and water conservation.