天然降雨条件下横垄与顺垄坡面产流产沙过程

Runoff and Sediment Yield Process on Longitudinal and Cross Ridge Slopes Under Natural Rainfall

试验以天然降雨为侵蚀动力,采用标准径流小区法,对比研究了连续型降雨与间歇型降雨条件下横垄与顺垄玉米径流形成和泥沙迁移规律。结果表明:连续型降雨产流过程形态呈"W"或倒"V"形,产沙形态呈"W"或"M"形;顺垄产流与产沙时间长度一致,产流总量和产沙总量分别是横垄的1.66~5.80倍和5.02~5.52倍;顺垄与横垄产流产沙峰值差异显著,仅横垄与雨强存在错峰现象,延后1min。间歇型降雨产流形态为倒"V"形,产沙形态呈倒"V"或"M"形;顺垄产流和产沙总量分别是横垄的1.83倍和2.32倍;首次产流量占总量的70%以上,产沙量占总量的94%~100%,且横垄和顺垄与雨强均存在错峰现象,顺垄产流和产沙量较雨强延后1~4min,横垄延后1min;除首次产流外,其余产流产沙过程时间较短均无错峰现象。天然降雨条件下,横垄与顺垄产流产沙过程较为复杂,研究结果可为区域坡地水土流失防治及水土资源管理利用提供理论依据。

In this experiment,the natural rainfall was taken as the erosion power and the st and ard runoff plot method was used to study the formation of runoff and sediment transport in the longitudinal and cross ridge slope tilled with maize.Results showed that under continuous rainfall conditions,the process of runoff appeared as a＂W-type＂or an ＂inverted V-type＂, and the sediment formation as a ＂W-type＂or＂M-type＂.The time length of runoff and sediment yield was the same on the longitudinal ridge, and the total runoff and sediment yield were 1.66-5.80 times and 5.02-5.52 times of those on cross ridge,respectively.There was a significant difference between the peaks of runoff and sediment yield on longitudinal and cross ridges, and the peak phenomenon was found only between cross ridge and rainfall intensity, and 1min was delayed.The process of runoff appeared as an ＂inverted V-type＂under intermittent rainfall, and the sediment formation were an＂inverted V-type＂or＂M-type＂.The runoff and sediment yield on longitudinal ridge were 1.83 times and 2.32 times higher than those on cross ridge, and the first runoff accounted for more than 70% of the total,the sediment yield accounted for 94% -100% of the total.Both cross and longitudinal ridges had the peak phenomenon with rainfall intensity, and the runoff and sediment yield were delayed by 1-4min with rainfall intensity on longitudinal ridge,1min on cross ridge.However,there was no peak phenomenon in the rest of rains.Under natural rainfall,the process of runoff and sediment yield was complicated on the longitudinal and cross ridge slopes.These findings could provide a theoretical basis for the prevention and control of soil erosion and the management of water and soil resources in regional sloping fields.