宁夏引黄灌区农田土壤酶活性及其空间变异

采集了同一地点不同土地利用方式,及不同地点不同典型土地利用类型下银川平原的灌淤土样品,在分析了土壤基本理化性质的基础上,用奈氏比色法、苯磷酸二钠比色法和高锰酸钾滴定法,分别测定了宁夏引黄灌区农田不同利用方式下土壤的磷酸酶、脲酶、过氧化氢酶的活性状况,并对土壤酶活性与土壤的基本理化性质的相关性进行了相关分析。结果表明,土地利用方式对三种酶活性有很大的影响。12年果园磷酸酶活性最高,常年旱田脲酶和过氧化氢酶活性最高,而盐化旱田及常年淹水的稻田,三种酶活性都很低。脲酶活性与土壤全氮之间显著正相关,全磷与三种酶活性都极显著相关,三种酶之间达到显著或极显著正相关关系。表明磷酸酶、脲酶和过氧化氢酶活性的大小可以敏感地表征宁夏引黄灌区土壤肥力和生产力的高低。

Soil enzyme activities and spatial variances in Yellow River irrigated area of Ningxia

It is widely accepted that high levels of microbial activity are fundamental in maintaining soil fertility. The microorganism is responsible for the nutrient cycling and the development and functionality of the soil system. Microorganisms play a fundamental role in carrying out biogeochemical cycles in soil and in maintaining soil fertility. There is growing evidence that soil microbiological and biochemical parameters may be used as early and sensitive indicators of soil ecological stress. Several microbiological parameters have been used to describe the status and sustainable development of soil productivity in agricultural ecosystems. Enzyme activity in the soil environment is considered to be a major factor contributing to overall soil microbial activity. Soil enzymes are biological catalysts of specific reactions and these reactions, in turn, depend on a variety of factors. Numerous studies on enzymes exist and comparisons have been made in various soils subjected to different management practices. Many studies have been showed that soil urease, phosphatase and catalase activity can be used to describe soil microbial activity. However, soil enzyme activities in relation to land cultivation changes has not been studied in Yinchuan plain. Such studies can provide a better understanding of sol fertility change following the change of land tillage. A laboratory analysis of soil phosphatase, urease, and catalase activities of irrigated area under different farmland cultivation was carried out. The result indicated that soil enzyme activities were greatly influenced by land management practices. Orchard has the highest level of phosphatase activity. Glebe has the highest urease and catalase activities. Yet paddy-field has the lowest phosphatase, urease and catalase activities. Regression analysis showed that significant correlation exist between urease and soil total N. Significant correlation has found between phosphatase and the three soil enzyme activities, and among the three enzymes. The results indicated that phosphatase, urease and catalase activity can be used as an earlier and sensitive indicator to indicate the soil fertility of Ningxia Yellow River irrigated area.