Influence of Water Management and Tillage Patterns on Nitrogen Utilization of Rice Yield and profitability of corn and soybean under different tillage in the black soils of Northeast China Effect of different tillage treatments on soil respiration of winter-wheat farmland in oasis irrigated area Northwest China Effects of long-term conservation tillage on soil physical quality of rainfed areas of the Loess Plateau Effect of long-term conservation tillage on soil fertility in rain-fed areas of the Loess Plateau Effect of tillage practices on soil microbial biomass carbon in the field with long-term non-tillage