次生马尾松林下植被恢复措施的水土保持效益

通过采集江西省赣县花岗岩区次生马尾松纯林地不同植被恢复措施坡面径流小区2010—2011年的降雨产流产沙资料,分析不同模式的水土保持功能及其植被恢复的水土保持效益。结果表明:1)次生马尾松稀疏纯林地水土流失严重,年产流系数为0.50～0.60,侵蚀模数在2 700～6 000 t/(km2.a)之间。2)植被恢复可以降低林地土壤侵蚀强度,但植被恢复的水土保持效益与林冠结构和地表覆盖度密切相关,当形成乔草或乔灌复合层时,可以起到50%～60%的年蓄水效益和65%～70%的年固土效益。3)植被恢复的水土保持效益亦受植被和降雨类型的影响,百喜草蓄水效益随降雨量先增后减,暴雨是蓄水效益变化的转折点,而胡枝子蓄水效益变化规律不一;植被恢复措施固土效益随降雨量的增加而降低,特别是在大暴雨情景时急剧下降。

Effects of different vegetation restoration patterns on soil erosion in secondary Pinus massoniana pure forest

in this study,based on the measured data of runoff and sediment of the runoff plots during 2010 to 2011 in secondary Pinus massoniana forest in the Ganxian County of Jiangxi Province,the benefits of soil and water conservation of different vegetation restoration patterns（Paspalum notatum,herbal;Lespedeza bicolor,shrub） in the secondary Pinus massoniana pure forest were analyzed.The results indicated that soil erosion is serious in secondary Pinus massoniana sparse pure forest,annual runoff coefficient was 0.50-0.60 and erosion modulus was in the range of 2 700-6 000 t/（km2·a）.Soil erosion intensity was reduced by surface vegetation restoration.However,the benefits of soil and water conservation of different vegetation restoration patterns were closely related to surface coverage and canopy structure.Benefits of water detention and soil conservation of vegetation restoration were 50%-60% and 65%-70% respectively when tree-herbal or tree-shrub structure formed a complex hierarchy in pure forest.Meanwhile,benefits of soil and water conservation were also affected by vegetation and rainfall types.Benefit of water detention initially increased then decreased with rainfall,and rainstorm was the inflexion for Paspalum notatum,and changed complex for Lespedeza bicolor.However,benefit of soil conservation reduced with rainfall,especially declined rapidly in heavy rainstorm.