敦煌市土壤理化性质分析及土壤质量评价

发布时间：2018-04-25 15:23

本文选题：敦煌市 + 土壤物理性质　；参考：《陕西师范大学》2015年硕士论文

【摘要】：土壤资源是一种非常脆弱的不可再生资源,维系土壤资源的数量和土壤的质量成为农业可持续发展的基础。敦煌地区生态环境极为脆弱,土壤盐渍化与荒漠化等退化现象严重,因此开展土壤性质的研究与土壤质量的评价对于缓解生态脆弱、提高环境质量、修复生态功能有着举足轻重的作用。本研究通过实地调研与土壤采样实测数据,采用相关分析、模糊综合评价等方法分析了敦煌土壤的粒度、含水量、盐分、PH、有机质、养分等理化性质特征,并对土壤质量进行了评价,得到以下结论：(1)研究区理化性质特征：土壤质地方面,土壤颗粒组成主要是粗粉粒和细沙粒所占比例最大,且随着土层深度的增加,有小幅度的波动变化。粘粒含量极低,介于中沙粒和粗砂粒含量之间。土壤含水量表层含量最低,随着深度的增加含水量增大。敦煌土壤均属于碱性土壤,PH均值范围为7.76～8.16。研究区有机质的含量随着深度的增加由良好变为缺乏。土壤养分纵向分布较为均一,土壤的全氮、有机质和有效氮含量低,全磷和速效磷的含量中等,全钾和有效钾的含量较高。总盐含量平均在7.7g/kg以上,各层土壤均为盐化状态,其中表层和中层属于盐分的积累层。土壤剖面的总盐含量与盐分离子含量具有很强的变异性,且离子的含量都是在表层表现出一定表聚作用,随着深度的增加呈现递减规律。敦煌表层土壤盐化情况较为严重,样品中约71%的土壤有盐渍化倾向和盐土倾向,是非盐渍化土的2.4倍之余。敦煌主要盐渍化土壤类型为硫酸盐盐化土,其次为硫酸盐-氯化物盐化土和氯化物-硫酸盐盐化土。(2)敦煌土壤性质相关分析特征：盐分离子中Mg2+、K+、NO3-与SO42-与中粉粒显著相关,Na+、Mg2+与粗砂粒有显著的相关性,其余盐分离子与各个粒级相关性不密切。总盐含量与黏粒、细粉粒、中粉粒呈显著正相关,而与粗粉粒、细沙粒、中沙粒和粗沙粒都呈显著负相关性。细颗粒对于盐分具有吸附作用,而较粗的颗粒不利于盐分的聚集。土壤总盐与各可溶性盐基离子、有机质之间呈显著正相关,其中有机质对Na+、Cl-的吸附性更明显,而对NO3-的吸附作用较弱。有机质与土壤含水量也具有显著相关性。土壤养分与土壤性质的关系：全钾、有效钾的含量与细粘粒、粗粘粒、细粉粒、中粉粒、粗粉粒这些较小粒径的含量呈显著正相关关系,有机质、全氮含量只与粗沙粒的含量呈负相关关系,与其他粒级含量相关性较弱。而全磷、有效氮、速效磷的含量与各粒级含量的关系都不密切。有机质与除钾之外的所有养分都呈显著相关。(3)不同环境下理化特征分析：敦煌主要采样地区中南泉湿地的土壤含水量最大,玉门关地区的最小,党河下游绿洲区和阳关地区含水量居中,含水量随深度变化不大,阳关地区的含水量小于党河下游绿洲区。敦煌主要采样地区中玉门关的盐分最高,其次是南泉附近地区和绿洲区,盐分最低的是阳关采样区。研究区不同植被群落土壤盐分中,生长黑果枸杞的土壤整体盐分最高,尤其是表层和上层,芦苇的土壤含盐量也较高,红柳和红柳+骆驼刺伴生的土壤含盐量均较小。研究区不同植被群落土壤养分中,红柳骆驼刺伴生的土壤有机质含量最多,黑果枸杞和红柳也较高,枯死的梭梭地有机质含量和全氮含量最少,各类型全钾和有效钾含量较高,且波动幅度较大。不同的土地利用类型对可溶性盐离子Na+、K+、Cl-、SO42-以及总盐均产生显著影响。盐分离子除Mg2+、NO3-之外其余离子与总盐都受土壤深度的影响较小,Na+、Cl-、SO42-和总盐的变化特征较为相似,由高到低排序都为荒地灌木林地农田果园,而K’与其他盐分离子不同,灌木林地含量高于荒地、农田和果园。土地利用方式对养分的影响中,果园和农田的全氮、全磷、全钾、有机质含量都比灌木林地的低,而物理性粘粒含量在农田中最高,荒地的有机质和物理性粘粒含量最少,农田和果园的速效养分中有效钾和有效氮的含量也比灌木林地低。荒地的全钾和有效钾都较高说明钾元素的含量与土壤的成土母质有关。(4)研究区土壤质量评价：敦煌四个不同采样区的土壤综合质量排序为南泉敦煌绿洲阳关玉门关,南泉地区土壤质量较高,敦煌绿洲区和阳关采样区土壤质量虽属于较高级别,但是由于人为活动的干扰导致质量次于南泉地区；玉门关采样区的土壤质量属于中等水平。不同植被群落土壤质量得分结果为：红柳+骆驼刺伴生红柳骆驼刺黑果枸杞梭梭芦苇枯死的梭梭,得分在0.54-0.86之间,土壤质量基本属于中等水平。不同土地利用类型对土壤质量的影响结果为：灌木林地果园农田荒地,有机质含量少导致农田和果园的土壤质量都低于灌木林地,同时也说明耕作活动会降低土壤的肥力质量,从而降低土壤质量。荒地由于生物量缺乏导致养分匮乏、盐分含量较高、土壤粒径较粗导致养分水分流失,故土壤质量最差。灌木林地和果园土壤的土壤都没有退化,而农田由于耕作有了轻微的退化,荒地的退化程度最严重。
[Abstract]:Soil resources are a very fragile non renewable resource. Maintaining the quantity of soil resources and the quality of soil has become the basis of sustainable agricultural development. The ecological environment in Dunhuang is extremely fragile, soil salinization and desertification are serious. Therefore, the study of soil properties and the evaluation of soil quality can be used to alleviate the ecology. This study has analyzed the characteristics of soil grain size, water content, salt, PH, PH, organic matter, nutrient and so on, and evaluated the soil quality by field investigation and soil sampling survey data, correlation analysis and fuzzy comprehensive evaluation. The following conclusions are as follows: (1) the characteristics of physical and chemical properties of the study area: soil texture, soil particle composition is the largest proportion of coarse particles and fine sand grains, and with the increase of soil depth, there is a small amplitude fluctuation. The content of clay particles is very low, between the medium sand and coarse sand content. The soil moisture content is the lowest, with the depth of the soil, with the depth of the soil. The water content of Dunhuang soil is increased. The soil of Dunhuang belongs to alkaline soil. The content of organic matter in the range of 7.76 ~ 8.16. is from good to lack. The vertical distribution of soil nutrients is relatively uniform, the total nitrogen, organic matter and available nitrogen in the soil are low, the content of total phosphorus and available phosphorus is moderate, and all potassium and available potassium are available. The total salt content is above 7.7g/kg, and the soil of each layer is salinization. The surface and middle layer belong to the accumulation layer of salt. The total salt content of the soil section and the salt ion content have strong variability, and the content of the ions shows a certain aggregation effect on the surface. With the increase of the depth, it presents a decreasing rule. Law. The salinization of the surface soil in Dunhuang is more serious. About 71% of the soil samples are salinized and salinized, 2.4 times more than that of non salinized soil. The main salinized soil in Dunhuang is kraft salinized soil, followed by sulfate chloride salinized soil and chloride thiate salinized soil. (2) the characteristics of soil properties in Dunhuang Mg2+, K+, NO3- and SO42- have significant correlation with the medium particles in salt ions. Na+ and Mg2+ have a significant correlation with coarse sand particles. The other salt ions are not closely related to the grain size. The total salt content is significantly positively correlated with the clay particles, fine particles and medium particles, but is negatively correlated with the coarse particles, fine sand grains, medium sand grains and coarse sand grains. The grain has an adsorption effect on salt, and the coarser particles are not conducive to the accumulation of salt. There is a significant positive correlation between the total salt of the soil and the soluble salt base ions and the organic matter. The adsorption of organic matter to Na+ and Cl- is more obvious, but the adsorption of NO3- is weak. The relationship between soil properties: total potassium, the content of effective potassium and fine clay particles, coarse clay particles, fine powder, medium powder and coarse silt have a significant positive correlation. The content of organic matter and total nitrogen is only negatively correlated with the content of coarse sand, and the content of total phosphorus, available nitrogen and available phosphorus is very weak. The relationship between the grain level content is not close. The organic matter and all nutrients except for potassium removal are significantly related. (3) the analysis of physical and chemical characteristics under different environment: the soil moisture content of Zhongnan spring wetland in Dunhuang main sampling area is the largest, the smallest in Yumen Pass area, the water content in the oasis and Yang Guan area of the lower reaches of the party river is middle, and the water content varies with the depth. The water content of Yang Guan area is less than that in the oasis area of the lower reaches of the party river. The salt content of Yumen Pass is the highest in the main sampling areas in Dunhuang, followed by the South Spring and the oasis, the lowest salt is the Yang Guan sampling area. In the soil salt of the different vegetation communities, the soil overall salinity is highest, especially in the surface and upper layer. The soil salt content of the soil in the reed is also high. The soil salt content of the red willow and the red willow and camel spines is smaller. In the soil nutrients of the different vegetation communities in the study area, the soil organic matter content is the most, the black fruit and the wolfberry and the red willow are higher, the organic matter content and the total nitrogen content of the dead Haloxylon ammodendron are the least, and all types of potassium and available potassium are all types. The different types of land use have significant effects on soluble salt ions Na+, K+, Cl-, SO42- and total salt. The salt ions are less affected by the soil depth except Mg2+, NO3-, and the changes of Na+, Cl-, SO42- and total salt are similar, and all from high to low are the wasteland. Shrub woodland farmland orchard, while K 'is different from other salt ions, shrub forest land content is higher than wasteland, farmland and orchard. In the influence of land use way to nutrient, the total nitrogen, total phosphorus, total potassium and organic matter content of orchard and farmland are lower than that of shrub, and the physical clay content is the highest in farmland, and the organic matter and physical property of wasteland The content of clay particles is the least, the content of available potassium and available nitrogen in the available nutrients in farmland and orchard is also lower than that of shrub land. The total potassium and effective potassium in the wasteland indicate that the content of potassium is related to the soil parent material. (4) the evaluation of soil quality in the study area: the comprehensive quality of soil quality in the four different sampling areas in Dunhuang is the South Spring of Dunhuang. The soil quality of the South Spring Area of the oasis Yang Guan Yumen Pass is high, although the soil quality of the Dunhuang oasis area and Yang Guan sampling area is higher, the quality of the soil in the Yumen Pass sampling area belongs to the middle level. The results of the soil quality score of the different vegetation communities are: the red willow + camel. The effect of different land use types on soil quality is that the soil quality of shrub woodland orchard is less than that of shrub land, and the soil quality of farmland and orchard is lower than that of shrub forestland. It also shows that farming activities can reduce the quality of soil fertility and thus reduce the quality of soil. The wasteland is poor because of lack of nutrients, high salinity and coarse soil size, resulting in the loss of nutrients, so the soil quality is the worst. The degradation of the wasteland is the most serious.

【学位授予单位】：陕西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S153;S158

【参考文献】