Field investigations of rainfall impact on soil erosion and soil surface roughness

摘要

Objectives of this field study were: 1) to compare effects of differently tilled base plots on runoff and soil loss; and 2) to investigate temporal change of different soil microtopographies. The experiments were performed during the growing seasonsin 1998 and 1999 on a field in the eastern part of Austria. Soil was a sandy loam with approx 16 percent slope. Three different tillage operations were compared: 1) rotary tiller, 2) chisel plough, and 3) moldboard plough. For each variation, three 1X1m runoff plots were installed in spring after tillage and kept bare throughout the whole growing season with no more tillage operations. Runoff and soil loss were collected and measured for each rainfall event. Precipitation was measured in 5 min intervals and recorded by an automatic data acquisition system. Surface roughness was measured for each plot in approx 8-10 day intervals depending on the rainfall with a reliefmeter (1998) and a portable laser device (1999). The measuring grid was 2.5 and 1.0cm depending on the methodology used. Highest runoff and soil loss were measured from rotary tilled plots. In both years moldboard plough tillage led to slightly higher soil loss than chisel plough. In 1998 runoff from chisel plot was higher than from moldboard plot, in 1999 it was exactly the opposite. For soil surface roughness, different indices were calculated and analyzed.