我国寒温带四种森林植被类型下土壤团聚体粒级组成及其稳定性比较研究

Composition and Stability of Soil Aggregates in Four Forest Vegetation Types in Cold Temperate Zone

为了探明我国寒温带大兴安岭地区四种森林植被下土壤的结构和稳定性,于2018年5月至10月对兴安落叶松林、樟子松林、山杨林和白桦林进行土壤样品采集,对四种植被类型0~5 cm、5~10 cm和10~20 cm土层土壤水稳性团聚体粒级组成及其稳定性指标(MWD、GMD和分形维数)进行了研究。结果表明:樟子松林、山杨林和白桦林0~10 cm土层以及兴安落叶松林的0~5 cm土层土壤在生长季内以大团聚体(>0.25 mm)占绝对优势,其他土层均以微团聚体(<0.25 mm)为主;且四种植被类型生长季中期三个土层的大团聚体含量均高于生长季初期和末期。0~5 cm土层四种植被类型土壤团聚体稳定性较高且相近,随土层加深土层团聚体稳定性降低。寒温带四种森林植被类型生长季内表层(0~5 cm)土壤水稳性大团聚体比例及土壤团聚体稳定性均高于下层(5~20 cm),且阔叶林大团聚体含量高于针叶林,但相对于国内其他研究地区较低。

In order to find out soil structure and stability under the four forest vegetation types in the cold temperate zone of China,soil samples were collected from may to October,2018 for the Larix gmelinii forest,Pinus sylvestris var.mongolica,Populus davidiana and Betula platyphylla,The particle size composition and stability index(MWD,GMD and fractal dimension)of water-stable aggregates in soil of 0-5 cm,5-10 cm and 10-20 cm were studied.The results show that:In the growing season,the soil in the 0-10 cm soil layer of Pinus sylvestris var.mongolica,Populus davidiana and Betula platyphylla and the 0-5 cm soil layer of the Larix gmelinii forest was dominated by macroaggregates(>0.25 mm).Other soil layers are dominated by microaggregates(<0.25 mm).The proportion of macroaggregates(>0.25 mm)at the middle growing season was higher than that at the early and late growing season.The soil aggregate stability was relatively higher at the 0-5 cm soil depth,The stability of soil aggregates decreases with the deepening of soil layer.The proportions of macroaggregates(>0.25 mm)and their stabilities at the topsoil(0-5 cm)were higher than those at the subsoil(5-20 cm),and were higher under the broad-leaved forest than those under the coniferous forest among the four forest vegetation types in the cold temperate zone.However,it is lower than other research areas in China.