Effects of different tillage methods on runoff, soil loss, and erosion related soil quality indicators on sloped cropland

Soil erosion is a major threat to the resource soil. Loss of topsoil as well as deposition of eroded material affect all functions a soil has to fulfill including soil productivity, filtering, buffering, de-grading and detoxifying. In 1994 a field experiment started at three locations in Lower Austria to investigate the effect of different tillage practices on crop yield, surface runoff, soil erosion, and nutrient and pesticide losses. The tillage practices include 1) conventional tillage, 2) conservation tillage with cover crop, and 3) no-till with cover crop. Eight years after initiation of this field study this project will investigate the impact of these tillage practices on soil quality. Overall objectives of this study are 1) to collect data to evaluate best management practices (BMP) for Austrian farming conditions, 2) to investigate the effect of conventional tillage, conservation tillage and no-till on soil physical, chemical and biological properties, 3) to investigate temporal and spatial variability of soil properties induced by soil management along a slope, and 3) to collect data to evaluate best management practices for Austrian conditions. The study design of the erosion measurements consists of 4 m wide and 15 m long runoff plots for each management variation. Inclination of hillslopes varies between 6 and 16 %. Runoff and sediments are collected for each erosive rain storm event with an automated measuring device. Nutrient (nitrogen and phosphorus) and pesticide losses associated with runoff and sediment are determined. To asses long-term effects of soil tillage/management on soil quality undisturbed and disturbed soil samples are taken at all three sites in different soil depths over the root zone and main physi-cal, chemical and biological soil properties are investigated. To investigate the effect of time and location along the hillslope on soil quality, three slope positions (summit, middle slope, footslope) are selected at each site. Soil moisture and soil tension are measured in weekly intervals to invest-igate possible differences in hydrologic condition. Soil samples are taken in appr. 4 weeks intervals and some physical, chemical and biological soil parameters are investigated. Crop yields are determined for each hillslope position. Improved soil physical, chemical and biological properties upgrade the ability of a soil to fulfill all functions like productivity, storage, filtering and buffering aso. Increased soil quality reduces also environmental risks like contamination of surface and groundwater bodies with nutrients or contaminants. The results of this project will also provide data for evaluation of BMP´s and information about sensitive areas in watersheds with respect to groundwater contamination.