大兴安岭火烧迹地土壤抗冲性研究

Study on Soil Anti-scourability of Burned Area in Greater Xing'an Mountains

为了探讨森林火灾对土壤抗冲性的影响,以大兴安岭地区三种不同火烧强度的火烧迹地为研究对象,采用原状土冲刷法对土壤抗冲性进行测定,并结合枯落物蓄积、持水性能及植物根系差异变化进行综合对比分析,结果表明:火烧迹地的土壤抗冲性显著低于未过火地段(P<0.01),随着火烧强度的增加,土壤的抗冲性能逐渐减弱,抗冲系数总体变化趋势为:重度火烧迹地<中度火烧迹地<轻度火烧迹地<未过火天然林。四种样地类型的枯落物蓄积量总体趋势为轻度火烧迹地<中度火烧迹地<重度火烧迹地<未过火天然林。4种样地类型的枯落物最大持水率及有效拦蓄率皆表现为重度火烧迹地<中度火烧迹地<轻度火烧迹地<未过火天然林。在浅层土壤中,重度火烧迹地的根密度及根系总长度均值皆为四者中最小。研究表明:未火烧天然林的土壤抗冲性表现最优,重度火烧迹地的土壤抗冲性能最弱,应与及时治理与植被恢复。

In order to explore the effects of forest fire on soil anti-scourability, the burned areas under three different fire intensi- ties in Greater Xing＇an Mountains were selected. Soil anti-scourability was determined through original soil scouring method. Further- more, comprehensive analysis was made through the difference of litter accumulation, water holding capacity and the change of plant root. The results showed that： Soil anti-scourability of burned areas was significantly lower than unburned areas（ P 〈 0. 01 ）. As fire intensity increased, the overall trend of soil anti-scourability was severe 〈 moderate 〈 mild 〈 CK. The overall trend of litter storage ca- pacity was ： mild 〈 moderate 〈 severe 〈 CK. Both of the maximum water-holding rate and modified interception rate of litter were ： se- vere 〈 moderate 〈 mild 〈 CK. In shallow soils, root density and the mean total root length of severe burned area were the smallest. In conclusion, soil anti-scourability of unburned area was best, soil anti-scourability of severe burned area was the weakest which should be managed and restored in time.