Abstract:
Rainfall erosivity reflects the potential ability of soil erosion caused by rainfall, which is the core of soil erosive risk assessment. The spatial-variations of rainfall erosivity in the Poyang Lake Basin were investigated based on daily rainfall data during 1961-2014. Results show that average value of rainfall erosivity was 9 537.9 MJ·mm·hm
-2·h
-1, and had an insignificant upward trend. Rainfall erosivity and its tendency rate increased from southwest to northeast of Poyang Lake Basin, but the trend for most of the stations was insignificant. The annual average value of concentration degree of the rainfall erosivity was 0.49 with an insignificant decreasing trend, while annual average concentration period was 152.4° (corresponding to June) with an insignificant increasing trend. Spatial distribution of concentration degree was similar to rainfall erosivity, while concentration period had no obvious distribution pattern in the Poyang Lake Basin. Spatial pattern of rainfall erosivity did not change in the recent six decade while the centre of the high (low) value area changed in different decades. Dynamic of concentration degree for the last six decade was in accord with rainfall erosivity, while concentration period had no evident distribution pattern.