Water and Nutrient Conservation Effects of Different Tillage Treatments in Sloping Fields

To provide a basis for reasonable tillage methods in farmlands in Water Wind Erosion Crisscross Region on the Loess Plateau, five conservation tillage treatments, no-tillage farming, straw mulching, plastic mulching, ridge mulching, and intercropping, were used in sloping fields. Soil moisture and organic carbon contents were measured by an oven drying method and dichromate oxidation method, respectively. Results showed that straw mulching, no-tillage farming, and plastic mulching could significantly improve subsurface water content. In the deep layer, no-tillage farming resulted in lower water content in contrast to straw mulching with higher water content. Straw mulching could effectively improve organic matter content in the arable layer and the average organic matter was 1.22% higher than in the no-tillage treatment, in which the organic matter content was the lowest. The available potassium content of straw mulching increased by 13.58mgkg(-1) for soybean and 16.30mgkg(-1) for millet during the late stage in contrast with the early stage. The available phosphorus under straw mulching increased by 0.07mgkg(-1) for soybean and 3.84mgkg(-1) for millet. Straw mulching proved to be the most advantageous in improving soil subsurface water content and conserving nutrients compared with the other methods.