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为研究不同用地方式对三峡库区消落带土壤性质的影响,选取三峡库区重庆忠县汝溪河流域典型消落带为研究区域,研究不同用地类型(草地、弃耕地、耕地)、不同土层间(0—10 cm、10—20 cm)土壤微生物、土壤酶活性和土壤化学性质的各自特征及其相互关系,旨在为该地区消落带生态恢复实践提供理论依据。研究发现:除蛋白酶活性、全磷含量、碱解氮含量外,不同用地类型对土壤各生化特性均产生了显著影响;与之不同,土层仅对细菌数量、放线菌数量、真菌数量、蔗糖酶活性、脲酶活性以及土壤有机质含量产生显著影响,但对其他生化性质影响不显著;用地类型与土层两者的交互作用仅对蔗糖酶活性影响显著。同时,弃耕地土壤的细菌数量在3种用地类型中最高;真菌、放线菌数量在草地中最高,耕地次之,弃耕地最低。弃耕地中的过氧化氢酶、蔗糖酶、蛋白酶和脲酶活性与其他两种用地类型相比较高,而耕地中磷酸酶活性则显著高于弃耕地和草地土壤。草地土壤全氮、有效磷以及速效钾含量均显著低于耕地,而草地0—20 cm土层的有机质含量却显著高于弃耕地和耕地;3种用地类型的全磷、全钾、碱解氮含量差异均不显著,弃耕地的pH值显著高于另外两种用地类型。另一方面,三峡库区消落带土壤的各生化指标间存在一定的相关性。pH值和微生物数量及酶活性间的关系最为密切,土壤真菌和放线菌数量与土壤有机质含量呈极显著正相关。研究结果表明,与弃耕地和耕地相比,草地在稳定消落带土壤环境、固持土壤营养元素、提高土壤肥力方面作用更为显著;相对而言,耕地的土壤微生态环境较差,故在消落带实施退耕还草、恢复草本植被等具有重要意义。
In order to study the effect of different land use patterns on the soil properties of the hydro-fluctuation belt in the Three Gorges Reservoir area, the typical fluctuation zone of Ruxi River Basin in Chongqing Zhongxian County, Chongqing Three Gorges Reservoir Area was selected as the study area. Different types of land use (grassland, abandoned farmland and farmland) The characteristics of soil microorganisms, soil enzyme activities and soil chemical properties in the soil layer (0-10 cm, 10-20 cm) and their correlations are intended to provide a theoretical basis for ecological restoration practice in the hydro-fluctuation belt of the area. The results showed that except for the activity of protease, the content of total phosphorus and the content of alkaline hydrolysis nitrogen, different types of land use had significant effects on the biochemical characteristics of soils. In contrast, only the quantity of bacteria, actinomyces, fungi, Invertase activity, urease activity and soil organic matter content, but had no significant effect on other biochemical properties. The interaction between land type and soil layer only had a significant effect on invertase activity. At the same time, the amount of bacteria in abandoned soil was the highest among the three types of land use. The number of fungi and actinomycetes was highest in grassland, followed by arable land and lowest in abandoned land. The activities of catalase, invertase, protease and urease in abandoned farmland were higher than the other two types of land use, while the activity of phosphatase in cultivated land was significantly higher than that in abandoned farmland and grassland. The contents of total nitrogen, available phosphorus and available potassium in grassland were significantly lower than those in arable land, but the content of organic matter in 0-20 cm soil layer in grassland was significantly higher than that in abandoned land and arable land. The contents of total phosphorus, total potassium, The difference of nitrogen content was not significant. The pH value of abandoned farmland was significantly higher than the other two types of land use. On the other hand, there is a certain correlation between the biochemical indexes of soils in the hydro-fluctuation zone of the Three Gorges Reservoir area. The relationship between pH value, microbial quantity and enzyme activity was the most closely related. The numbers of soil fungi and actinomycetes were significantly and positively correlated with soil organic matter content. The results showed that compared with abandoned farmland and cultivated land, the grassland played a more significant role in stabilizing the soil environment, maintaining soil nutrient elements and improving soil fertility. Relatively speaking, the soil micro-ecological environment of cultivated land was poor, It is of great significance to implement the plan of returning farmland to grassland and restoring herbaceous vegetation in the ebb zone.