不同土地利用方式下土壤抗冲性动态变化特征及其影响因素

Soil Anti-scourability Dynamic Variation Characteristics and Its Influencing Factors under Different Land Use Types

采用原状土冲刷槽法,以桉树人工林、茶园、撂荒地、枇杷园、杉木人工林土壤为研究对象,研究了土壤抗冲性动态变化特征及其影响因素。结果表明：土壤初始径流含沙量均较大,但随着冲刷时间的延长径流含沙量逐渐降低,并在3~6 min后逐渐趋于稳定;土壤抗冲性能随冲刷时间的延长呈波状变化,但总体上仍符合随冲刷时间延长,抗冲性增强的规律;土壤抗冲性能随冲刷时间的变化可用幂函数方程很好的拟合,其相关指数介于0.717-0.989;土壤抗冲性主要受容重、坡度、植物根系等因素的影响,其中〈1 mm须根是增强土壤抗冲性能的关键因子。〈1 mm须根根长、根表面积、根体积与土壤抗冲性强化值ΔANS呈显著或极显著正相关,其相关系数介于0.926~0.980。

On the basis of undisturbed soil sample washing method,soil anti-scourability dynamic variation characteristics and its influencing factors were studied under five land use types including Chinese fir plantation,eucalyptus plantation,loquat orchard,tea plantation and abandoned land.The results showed that the sediment concentration of all land use types was high at the beginning,then decreased gradually along with the scouring time after 3 to 6 minutes.Soil anti-scourability assumed wavy variation along with scouring time.And it also accorded with the law that anti-scourability increased gradually with scouring time.The change regulation of the index of soil anti-scourability along with scouring time obeyed the power function.The fitting effect was good and its correlation index lied between 0.717～0.989.Soil bulk density,slope and fibrous root were the main factors of soil anti-scourability under different land use types.In which,1 mm fibrous root was the key factor enhancing soil anti-scourability.Root length,surface area and volume of 1 mm fibrous root were significantly positive correlation to the enhancement value of soil anti-scourability.The remarkable position coefficient between them lied between 0.926～0.980.