Abstract:
Objective The erosive rainfall standard is a key indicator for calculating soil loss. The formulation of the erosive rainfall standard is closely related to the tillage method. Comparing the difference of the erosive rainfall standards under different tillage methods in the same area is of great significance for improving the accuracy of regional soil erosion forecasting.
Method Based on the rainfall-runoff observation data of runoff plots in semi-arid region of Northeast China from 2013 to 2019, the erosive rainfall standards under several typical tillage patterns were formulated by using frequency analysis method.
Result (1) compared with bare land plot (4.45 mm), the average value of seven-year erosive rainfall standard of horizontal ridge plot ( 9.6 mm), along ridge plot (11.65 mm) and ridge plant zone plot (21.15 mm) increased by 2.16, 2.62 and 4.75 times, respectively. (2) With the increase of years, the relative error of erosive rainfall standard decreased, the coefficient of variation decreased and the qualified rate increased. The qualified rate of erosive rainfall standard reached 100% when selecting 5-year data series of bare land plot, horizontal ridge plot, along ridge plot and ridge plant zone plot. (3) The larger the runoff coefficient was, the more the runoff production times were, and the smaller the erosive rainfall standard was.
Conclusion The comparison of different tillage patterns showed that horizontal ridge plot, along ridge plot and ridge plant zone plot could effectively improve the erosive rainfall standard, of which the ridge plant zone plot is the most significant one. Five-year rainfall data could meet the determination conditions of the erosive rainfall standard. The benefit of sediment and flow reduction is the best in the ridge plant zone plot, followed by the horizontal ridge plot and along ridge plot. The results could provide a certain reference basis for the comprehensive management of soil and water conservation in the semi-arid area of Northeast China.
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