坡面植被格局对坡沟系统能量调控及水沙响应关系的影响

Effects of Slope Vegetation Patterns on Energy Regulation and Water-Sediment Response Relations in Slope-Gully System

通过室内放水冲刷试验,研究在坡沟系统土壤侵蚀过程中,不同坡面植被格局对能量的调控作用及其对水沙响应关系的影响,并建立不同坡面植被格局下基于能量参数的侵蚀产沙方程,深入了解能量与侵蚀产沙之间的响应关系。结果表明:(1)相比于裸坡,在坡面有植被覆盖的情况下,径流功率大幅度降低,植被能够有效地削减径流功率,起到保护土壤的作用;在不同时刻下,不同坡面植被格局的单位水流功率在坡面较小,进入沟道后单位水流功率急剧上升,呈"N"形曲线分布,经过SPSS软件分析,坡面植被格局对单位水流功率的影响不显著(P>0.05);坡面植被格局对径流能耗的变化基本没有影响,不同时刻,不同坡面植被格局下坡面上每个断面的径流能耗在1 500~2 000J保持不变,在进入沟道后径流能耗急剧上升,达到4 800J左右;(2)在坡沟系统的坡面上种植植被可以有效地起到蓄水减沙的作用,当草带位置距坡顶2m时(格局F)的蓄水效益最好,达到19.07%,当草带位置距坡顶6m时(格局B)的减沙效益高达69.02%;(3)不同坡面植被格局下坡沟系统的累积产流量与累积产沙量之间满足M=aQb的幂函数形式,而且相关系数a和b可以作为蓄水减沙效益的指示指标;(4)在不同坡面植被格局下,坡面平均输沙率与径流功率满足D=cω+d线性函数关系。

In order to investigate the effects of different slope vegetation patterns on energy regulation and the relationships between water and sediment,an indoor scouring experiment was set up.The erosion and sediment yield equation under different slope vegetation patterns was established based on the energy parameter for the in-depth underst and ing of the response relationships between energy and sediment yield.The results showed that：（1）Compared to the bare slope,the runoff power greatly reduced under slope vegetation cover condition,indicating that vegetation could effectively reduce runoff power and protect the soil.At different times,unit stream power was small in the slope,but rapidly increased when flowing into the trench,showing a＂N＂shape curve.SPSS analysis showed that effects of slope vegetation patterns on the unit stream power was not significant（P 0.05）, and little effect on the change of the runoff energy consumption was observed.At different times,the slope surface runoff energy consumption on each section in different slope vegetation patterns ranged in 1 500~2 000 J,but increased sharply in the channel,up to about 4 800 J.（2）Planting vegetation on the slope of slope gully system could effectively play an important role of water storage and sediment reduction.When the distance between grasses strip to the slop top was 2 m（pattern F）,the water storage efficiency was up to 19.07% , and when the distance was 6 m（pattern B）,thesediment reduction rate was as high as 69.02% .（3）The cumulative runoff yield and cumulative sediment yield in different slope vegetation patterns showed a functional relationship of M=aQb, and the correlation coefficient a and b could be used as indicators of water storage and sediment reduction efficiency.（4）There was a linear relationship between runoff power and average sediment transport rates in different slope vegetation patterns,the functional form was D=cω＋d.