火烧对不同林型下森林土壤水分物理性质的影响

Effect of Fire on Soil Hydro-physical Properties under Different Types of Forest Land

通过对大兴安岭松岭林区白桦林、落叶松林以及白桦落叶松混交林的当年高强度火烧迹地与对照样地的土壤水分物理性质进行测定和比较研究。结果表明：在火烧迹地和对照样地无论是土壤容重、土壤孔隙度、土壤持水量还是贮水能力，0～10cm土层土壤都较10～20cm土层土壤优越，火烧没有改变随深度变化的趋势，但相差明显增高。3种林型相比，在对照样地，白桦林土壤通气性优于落叶松林，而在火烧迹地，落叶松林优于白桦林。无论是在对照样地还是火烧迹地，落叶松林土壤的持水量平均值均大于白桦林，而白桦林土壤的平均贮水能力优于落叶松林。总体上看，在研究地区无论是土壤通气性、土壤持水量还是贮水能力，白桦林和落叶松林都较白桦落叶松混交林优越。火烧迹地与对照样地相比，火烧对3种林型的影响趋势相同，即土壤容重增加，土壤平均孔隙度以及土壤持水量减小。

Soil hydro-physical properties under Betula platyphylla forest, Larix gmelini forest and Betula platyphylla - Larix gmelini mixed forest on Songling of Daxing＇an mountain during the same year of high intensity fire were studied. It is showed that in the three type forests, soil properties of 0-10 cm soil layer were better than 10-20 cm soil layer, and fire did not change the pattern with depth, but increased the difference obviously. These properties included soil bulk density, soil porosity, soil moisture capacity and soil water storage capacity. Comparement of three forest types, in unburned forest, soil aeration of Betula platyphylla forest was better than Larix gmelini forest, while in burned forest, soil aeration of the latter was better than that of the former forest type. Soil average moisture capacity of Larix gmelini forest was higher than that of Betula platyphylla forest, while soil average water storage capacity of the former was lower than that of the latter forest type. Overall, soil properties, such＇as soil organic matter, soil moisture capacity and soil water storage capacity of Betula platyphylla and Larix gmelini forest were better than that of Betula platyphylla - Larix gmelini mixed forest. The high intensity fire increased the soil bulk density, and decreased soil average porosity and soil moisture capacity for the three type forests.