沙棘林根系强化土壤抗冲性的研究

Intensification effects on soil anti-scourability by the Sea Buckthorn root system

本文采用剖面壁法和原状土冲刷水槽法,定量研究了8—12龄沙棘林地不同土层深度处根系强化土壤抗冲性的作用及其有效性。结果表明,当坡度≤20°,雨强≤2.0mm/min 时,A 层内的根系强化土壤抗冲性的作用不受雨强及坡度的影响。当坡度>20°,雨强>2.0mm/min 时,根系增强土壤抗冲性的效应随坡度或雨强增大而减弱。根系强化土壤抗冲性的功能与有效根密度在 P<0.001水平呈幂函数(△AS=A·R_(BD))的正比关系,其多少决定根系提高土壤抗冲性能的大小。根据对根提高土壤抗冲性的效应曲线的分析,以根系土壤相对冲刷量减少值大于50%为基准,确定出沙棘林固土的有效根密度在坡度≤20°和>20°时分别为60个/100cm^2和118个/100cm^2以上,根系固土的有效深度在坡度为15°、20°和30°时分别为40cm、30cm 和120cm 土层。

The intensification effects and increasing range in soil anti- scourability by the sea buckthorn roots distributing in different soil Layers have been quantitatively discussed in the paper.The results show that the intensification value of soil anti-scourability by the roots is not influ- enced by slope and rainfall intensity in A horizon,this effects,however, become weakened in other genetic horizons with the increase in slope or rainfall intensity.The studies also prove that the intensification value is closely correlated with the root(≤1mm)density(P<0.001).Based on the analysis of the increasing effect curves in soil anti-scourability and de- creasing effect in the amount of washed soil by the roots,a range of root density obviously intensifying soil anti-scouribility and a limit depth of fixing soil by sea buckthorn root system have been suggested.