Abstract:
Objective To find out whether added organic materials can enhance the ability of Black soil to resist mechanical disturbance in cultivated land.
Method Based on the farmland soil from typical black soil region under long-term mechanical operation, the constant temperature-humidity culture experiment were set up with 10 treatments after adding three different exogenous organic materials (straw, biochar, pig manure) with different content gradients (low amount, normal returning amount, high amount), and then mechanical disturbances of four intensities (0, 500, 1500 and 4500 J) were conducted to explore the effect of mechanical disturbance on the aggregates’ stability in the treatments of adding exogenous organic materials.
Result The mean weight diameter, geometric mean diameter and percentage of aggregate destruction were significantly influenced by the type and the amount of material, and the intensity of mechanical disturbance. The mean weight diameter of soil aggregate after adding straw was 1.40 and 1.23 times of biochar and pig manure, respectively. And geometric mean diameter was 1.22 and 1.12 times of biochar and pig manure, respectively.
Conclusion Adding straw can significantly improve the ability of Black soil aggregate to resist mechanical disturbance, following by adding swine manure, and no significant improvement by adding biochar. Mechanical disturbance and organic material amendment both have the significant effect on > 1 mm aggregate. Therefore, the > 1 mm aggregate is suggested to be used to evaluate the ability of black soil to resist mechanical disturbance, and the effect of organic material amendment for cultivated land.
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