松嫩平原沙土区不同植被类型对土壤相关指标的影响

Influences of Different Vegetation Types on Soil Parameters in Degraded Sandy Lands of Songnen Plain

松嫩平原沙土区严重退化,不同植被对土壤影响的数据有助生态恢复,但相关数据匮乏严重。本研究以松嫩平原核心区新店林场的农田、草地、杨树林、落叶松林、樟子松林和榆树林等6种植被为研究对象,采集三层（0～20、20～40和40～60 cm）土样,测定土壤理化指标（容重、土壤含水量、土壤p H、土壤电导率、有机碳、碱解氮、全氮、速效磷、全磷、速效钾、全钾）及根系密度、根系含水量。结果如下：6种植被在整个土壤剖面上显著影响了13个指标中的8个指标（根系密度、容重、土壤含水量、土壤p H、土壤电导率、全氮、根系含水量、有机碳）,其中根系密度植被间差异在不同土层显著不同（交互作用,P〈0.05）,而其它7个指标在不同土层的种间差异基本一致（交互作用,P〉0.05）。与林地和农田相比,草地具有最大的根系生物量,达到农田的1.8倍,是4种林分平均值的1.4倍。容重、土壤含水量、p H、土壤电导率值均草地最高,林地最小。土壤有机碳的累积受根系密度和容重影响明显,土壤氮除了受上述两个因素影响外,还受土壤含水量的影响。上述结果说明草地对于表层土壤生物固着明显,而人工造林能够改善土壤物理性质、降低盐碱但增加耗水,这些结果对于西部沙土区通过植被恢复来实现土壤修复提供数据支撑。

Data scarcity on the relations between vegetation types an biological rehabilitation of degraded lands, particularly in the degraded d soil properties have hindered the sandy lands of Songnen Plain with overburden human actives. With six vegetation types, farmland, grassland, poplar forest （ Populus spp. ）, larch forest （ Larix gmelinii）, pine forest （ Pinus sylvestrys var. mongolica）, and elm forest （ Ulmus pumila ）, around the Xindian forest farm, we measured the soils from 0 -20, 20 -40 and 40 -60 cm for soil bulk density, soil moisture, soil pH, soil electrical conductance （EC）, soil organic carbon （SOC）, alkali-hydrolyzed nitrogen （ AN）, total nitrogen （ TN ）, available phosphorus （ AP）, total phosphorus （ TP）, available potassium （ AK）, total potassium（TK） and root density, and root water content. Despite large differences in vertical soil profile, root density, soil bulk density, soil moisture, soil pH, EC, TN, root water content, and SOC were significantly influenced by six vegetation types. Besides vegetation-dependent significant differences of root density markedly different from different soil layers （ depth × vegetation interaction, P 〈 0.05 ）, the other seven parameters showed the same vegetation-related differences throughout whole 60 cm soil profile. Much higher fine root biomass in grass land, compared with forest （ 1.4-fold on average） and farmland （ 1.8 fold）, indicated its greater advantage in fixing sandy soil. Much lower pH, EC, soil bulk density and soil moisture in different forests, the peak values in grassland, manifested the afforestation effects in improving soil physics and compared with decreasing soil alkali-degree with more water consumption. By correlation analysis, SOC accumulation and N were related with root density, bulk density and soil moisture, while P supply was related with soil pH and EC. Our results would provide the basic data to support soil remediation through revegetation in Son,hen Plain.