黄土丘陵区不同土地利用类型下土壤酶活性和养分特征

Characteristics of soil enzyme activities and nutrients under various landuse in the Loessial hilly-gully region

研究了土地利用类型对土壤酶活性和土壤养分的影响。首先通过最小显著性差异(LSD)评价各样地之间和同一样地土壤剖面四个不同层次的土壤酶活性和养分的差异,其次分析四种土壤酶(转化酶、碱性磷酸酶、脲酶和过氧化氢酶)活性和土壤养分之间相关性;最后以农地为对照,应用土壤恢复指数研究不同土地利用类型对土壤的改良效果。研究结果表明,同农地相比,不同土地利用类型的表层(0～5cm)土壤四种酶活性、全氮、有机质和碱解氮含量均有所提高,且在同一土地利用类型下表层土壤酶活性和养分均显著大于下部各土层。相关性分析表明,土壤四种酶活性与有机质、全氮、碱解氮呈极显著正相关关系。同农地相比,其余土地利用类型表层土壤质量显著提高,而以杨树、侧柏、油松、仁用杏和刺槐5种人工林地的土壤质量提高最为明显,同龄树种中,杨树对土壤的恢复效果大于刺槐和油松。

The effects of landuse types on the soil enzyme activities and nutrients were studied in this paper. Least significant difference （LSD） method was used to analyze the differences of soil enzyme activities and nutrients in different soil layers of the same landuse and among various landuse types. Relations between soil enzyme activities of invertase glucose, alkaline phosphatase, urease, and catalase and soil nutrient were analyzed. The soil restoration index was used to evaluate the effects of landuse on the soil quality compared with cropland. Results showed that compared with cropland, topsoil （0-5 cm） enzyme activities, total nitrogen, organic matter, and alkali-hydrolyzed nitrogen had improved under different landuse types; and at the same landuse, topsoil enzyme activities and nutrients were higher than those of other deep layers. Correlation analysis showed that there existed significant correlation between soil enzyme activity and soil organic matter, total nitrogen, and alkali-hydrolyzed nitrogen. Soil restoration index showed that compared with cropland, topsoil quality under different landuse types had improved significantly, especially for five kinds of forest landuse types （Platycladus orientalis, Pinus tabulaeformis, Robinia pseudoacacia, populus, and Armeniaca）. Under the same age, soil quality restoration at poplar （populus） land was higher than that of Robinia pseudoacacia land and Chinese Pine（Pinus tabulaeformis） 4land.