水保所知识产出(1956---)知识库

Nitrogen deposition has great effects on vegetation characteristics and then affects soil erosion.
This study was conducted to quantify the effects of vegetation characteristics induced by nitrogen
addition on runoff and sediment yield. The Bothriochloa ischaemum (Linn.) Keng. was planted and
applied NH 4 NO 3 at levels of 0, 2.5, 5, and 10 g N m -2 yr -1 for three years with the bare soil for control.
Then all treatments were subjected to simulated rainfall (1.0, 1.5, and 2.0 mm min -1 ). Results showed
that nitrogen addition increased plant coverage, height, and aboveground biomass of N 2.5 , N 5 and N 10
treatments, while the root mass density of N 10 was the minimum. The grassplots significantly delayed
runoff starting time, reduced runoff and sediment yield. With nitrogen addition increasing, runoff
starting time delayed and runoff amount decreased, although no significant difference of runoff amount
was found under the high rainfall intensity. Moreover, sediment yield would be well estimated by runoff
mount, coverage and root mass density with a power function. 5 g N m -2 yr -1 seems the optimal nitrogen
level in controlling soil loss due to its minimum sediment yield. The different effects of nitrogen
addition on grassland community and soil erosion process identified in this study may facilitate the
simulation and prediction of soil erosion in semiarid grasslands under future scenarios of global change.