【作者】 丁菡；

【导师】 胡海波；

【作者基本信息】 南京林业大学 ， 生态学， 2003， 硕士

【摘要】 西部大开发倡导生态先行，为探讨我国干旱区土壤的生态特性，为土壤开发利用提供基础资料，本课题选择宁夏沙湖典型区域作为试验点，对土壤生态特性的各项指标进行了调查分析，其主要结果如下： (1)该地区土壤物理性质存在较大差异。土壤机械组成表现为粉粒含量最高，平均为45.03％；粘粒含量最低，平均为24.69％。砂粒含量居中，并且在各样地和各层间差异都很显著，可作为区别该地区土壤质地的主要因素。土壤含水量较低，最小的含水量不到1％，土壤含水量从表层至深层逐渐增加，且各层间差异显著。土壤容重在剖面中从上至下逐渐增大，相应的土壤孔隙度从上至下逐渐减小，它们在各样地间差异不显著，但在各层间差异达极显著水平。土壤抗蚀性随土层加深有增大的趋势。 (2)土壤化学性质也因不同土壤类型有一定的异质性。该地区土壤碱性较强，pH值均大于8。表土层pH值相对较低，植物根系含量丰富，枯枝落叶层较厚，改善了土壤酸碱性。该地区土壤有机质含量均很低，平均还不到1％。表土层有机质含量最高，且随着土层深度增加，有机质含量逐渐降低。土壤有效磷含量比较稳定，而速效钾各样地间具有显著差异，但土壤剖面各层间无显著差异。土壤含盐量较高，平均达到1110.34mS／cm，表土层最高，下层较低。 (3)土壤理化性质间关系错综复杂，各因素间均具有一定的相关性。pH值、有机质、粘粒含量均对土壤中速效钾含量产生极大的影响。总孔隙度与容重均与有效磷含量重有很大的相关性。含水量与容重、总孔隙度、粘粒含量、砂粒含量之间也具有密切的相关性。另外粉粒含量、砂粒含量、pH值均与抗蚀性关系密切。 (4)土壤微生物量及酶活性也存在一定的特点。土壤微生物量在各样地间具有显著差异，同时各样地随土层深度增加，微生物量总体呈减少趋势。土壤微生物量与土壤容重，总孔隙度和有机质含量有着非常密切的关系，与速效钾含量也有一定的关系，而含水量也在很大程度上影响到微生物的数量。该地区不同的土壤酶活性差异很显著，蔗糖酶活性较大，三种磷酸酶活性均较小。各种土壤酶活性在各样地的各层中变化趋势非常一致，随着土层深度增加而减少。制约各种酶活性的理化性质并不相同，其中，有机质含量与酶活性的正相关关系最密切。土壤微生物含量与各种酶活性之间均有密切的关系，可依据土壤微生物量与酶活性将该地区土壤分为两类进行考虑。更多还原

【Abstract】 As we know, ecology problem must be placed at the first in the west development. The experimental plots were located in Shahu of Ningxia autonomous region in order to investigate and analysis this area’ soil physical and chemical properties, biological activity and so on. This will be benefit the soil exploitation and utilization of these kinds of regions in the future through providing some basic data and materials. The main results obtained are as follows:1. The soil physical and chemical properties are very different in this region’s different plots. As far as soil texture is concerned, the content of silt particles is highest with the average of 45.03% and the content of clay particles is lowest with the average of 24.69% in every soil separates. The content of sandy particles is in middle and it was variation in all different plots and soil layers, so we can mainly dependent in the content of sandy particles to distinguish different soil texture in this region. The soil water content is very low, and the lowest value is less than 1%. The soil water increased from the top layer to the bottom layer with the great variances in different layers. The bulk density is increased from top layer to the bottom layer, meanwhile the soil porosity is decreased. The bulk density and the soil porosity are significant vary in different soil layers and are even in different plots. The soil erodibility presents a increased trend with the deepening of the layers.2. The soil’s chemical properties also present theirs distinguishing features. The PH value is very high in this region for all plots’ PH value are higher than 8. The top soil layer is lowest in pH value, because there are more trees or grasses’ organism that can improve the soil’s chemical properties. This region is short of soil organic matter for the average value is less than 1%. The content of soil organic matter is highest in the top layer and decreased from top layer to bottom layer. The soil available P is even in every plot’s soil, but the available K is obviously vary in different plots. The soil salinity is very high in this region with the average of 1110.34mS/cm. The highest salinity is discovered in the top layer, and the trend is decreasing with the deepening of soil layer.3. The relationships among all soil physical and chemical properties are very perplexed. pH value, organic matter and clay particles all take great effects on available K. There are significant correlation among porosity, bulk density and available P. The properties that mostly related with soil water content are bulk density, porosity, clay particles and sandy particles. Besides, clay particles, sandyparticles and PH value all exist closer relationship with soil erodibility.4. The soil microorganism amount and soil enzyme activity present diversity in all plots. There is significant discrepancy in different plots’ soil microorganism amount. The trend of soil microorganism amount in soil’s different layers is the amount decreasing when the layer deepen. The soil micro-organism amount is affected by soil bulk density, porosity and soil organic matter and exist some relationship with available K. The soil water content also affect microorganism amount by a large extent. In this region, different soil enzyme present different activities and principles. The invertase is mostly active, while three kinds of phosphates are all less active than other soil enzyme. Their trend in different soil layers of different plots is identical, they all decrease when the layer deepen. The factors of affecting each kind of soil enzyme are different. Especially, the soil enzyme present the closest relationship with the soil amount of organic matter. This region’ soil can be divided by two groups through their characteristics of microorganism amount and soil enzyme.更多还原