紫色土坡耕地植物篱的水土保持效应研究

Effects of Hedgerow on Soil and Water Conservation in Sloping Cropland of the Purple Soil

在四川盆地紫色土区通过标准径流小区试验,研究新银合欢(Leucaena leucocephala,豆科银合欢属)植物篱、香根草(Vetiveria zizanioides,禾本科香根草属)植物篱对坡耕地水土流失和微地形的影响。结果表明:10°,15°坡耕地上,新银合欢植物篱和香根草植物篱均表现出一定的水土保持效应,此效应需要约2年时间才开始显现。据2010年和2011年径流小区的水土流失监测数据知,植物篱对泥沙的控制效应优于对径流的控制效应;同坡度时,香根草植物篱对径流泥沙的拦截效应优于新银合欢植物篱;定植时间较长时,植物篱的减流减沙效益较好,尤其表现在固土减沙方面;坡度对径流泥沙的影响显著于植物篱对径流泥沙的影响,但定植植物篱2年,二者对径流泥沙的影响差距缩小。此外,定植植物篱2年,植物篱改变坡耕地微地形的效应开始显现,篱带前出现泥沙淤积带,篱带间农地坡度变缓,篱带下出现土坎,此种现象以15°坡耕地比10°坡耕地、香根草植物篱小区比新银合欢植物篱小区、底行植物篱带处比中行及顶行植物篱带处稍明显。

Through experiments in standard runoff plots in the purple soil area of Sichuan basin, this paper studied effects of Vetiveria zizanioides hedgerow and Leucaena leucocephala hedgerow on soil erosion and microtopography in sloping cropland. The results showed that in sloping cropland of 10° and 15°, both Leucaena leucocephala and Vetiveria zizanioides hedgerows showed soil and water conservation effects after a previous process about 2 years. According to monitoring data of these plots in 2010 and 2011, the two kinds of hedgerows had better control effect on sand sediment than surface runoff. With the same slope, Vetiveria zizanioides hedgerow demonstrated better ability than Leucaena leucocephala hedgerow on controlling soil erosion. The longer planted time was, the better effect of hedgerow on soil and water conservation was, especially reducing sediment. Slope showed more obvious effect on soil erosion than hedgerow, but this phenomenon changed next year. In addition, changes of microtopography of sloping cropland in hedgerow plots were started to show after planted 2 years, as sand deposition before hedgerow lines, slope decreased between two hedgerow lines and ridges formed under hedgerow lines. The hedgerow of Vetiveria zizanioides changed microtopography more significantly than that of Leucaena leucocephala, so as 15° to 10°, bottom hedgerow line to middle and top hedgerow lines.