Effects of Different Improved Materials on Soil Structural Characteristics under Different Unit Weight Gradients

In view of the ecological and environmental problems, such as excessive soil compactness, thickening of the bottom layer of the plough and upward shift, reduction of the number of soil aggregates, and deterioration of structural stability in Guanzhong area, combined with field monitoring and indoor simulation experiments, the improvement of soil structure by the addition of plant ash, organic fertilizer and biochar at different bulk density levels of 1.0, 1.1, 1.2, 1.3, 1.4 and 1.5 was analyzed. With the gradual increase of bulk density, soil compactness and compaction density show an increasing trend, and soil porosity shows a decreasing trend. The soil water content becomes a downward trend when the soil bulk density is 1.1, and an upward trend when the soil bulk density is 1.4. When the soil bulk density is 1.2 and 1.3, the plant height of crops is higher. Under different gradients of unit weight, plant ash has the greatest impact on plant height of crops, biochar has the greatest impact on soil compaction density and water content, and organic fertilizer has the greatest impact on soil porosity. In the process of soil compaction in Guanzhong area, if the water supply is sufficient in this area, the soil environment with plant ash is more favorable for plant growth and development. If water is the main limiting factor, adding biochar is the best measure to improve soil structure.