Experimental Study On Effects Of Different Soils On Rill Erosion

Rill erosion plays an important role in soil erosion process in loess hillslopes. It is a quantum leap during the process of soil erosion on slopes, and also is the beginning of a qualitative change in the process of soil erosion, it is the foundation of study of the development process of soil erosion. It is necessary to study on the influencing factors of rill erosion; many scholars have been attracted to related studies. Using the typical soil from two different soil (lou soil, cultivated loessial soil), a series experiments were conducted, two different soil bins(5m×1m,10m×1.5m), on slopes of10°、15°、20°nd25°, equal rainfall(1.5mm/min×60min,2mm/min×45min). And the3D laser scanner was used to make the real-time monitoring of the slope pattern after each rainfall, by analyzing the data, the effects of slope, slope length and rainfall on the rill erosion were each studied. The main research results are as follows:1. Runoff rates changed no significant regularity with the slope, erosion holes appeared earlier when the slope became higher. They were controlled by rainfall intensity. The slope length became longer to promote the erosion holes happened.2. Runoff was climb up and then decline with the increasing of slope, when the in total rainfall is same, different rainfall intensity, runoff difference is not big, there may be a runoff critical slope exist. Runoff rate in10minutes after the start of a trend of increase with the rapid, then slowly increase, until achieve stability infiltration and runoff.3. Slope sediment production quantity and slope significant positive correlation, the relationship between the two can use second to express a fitting, As the slope steepness increased, the slope sediment production quantity augmented at begging and then abatement. Rill breadth depth ratio with a steeper slope, became smaller, rill density, rill erosion and the slope were very significant positive correlation, The development of rill from slope surface from local to completely with the increasingly of the slope, when the slope is20°, the rill was development the whole slope, and the groove wall power channel at25°. 4. Lou soil infiltration rate was slow, runoff and erosion holes were earlier than cultivated loessial soil. Flow velocity was faster, that leaded to the rill more easily to produce. The runoff of Iou soil was more than cultivated loessial soil, easy to stable, lou soil slope erosion was higher also, Sediment rate were the increasing between rainfall process. The rill of the lou soil was arrayed in parallel, and the rill of the cultivated loessial soil was wider arborization.