陕西渭北农田土壤盐碱化空间分布及影响因素

发布时间：2018-06-13 08:28

本文选题：渭北地区 + 盐碱化　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：为明确陕西省渭北地区农田土壤盐碱化空间分布和主要影响因素,给区域耕地资源合理利用和低产田改良提供决策支持,以渭河以北、渭北低山及两侧的黄土高原和台塬为研究中心,通过实地调查、土壤采样和室内分析的方式,获得渭北地区0~60 cm土层的盐碱化数据及相对应的空间、土壤性质、地下水、作物产量数据,对土壤盐碱化程度的分布状况进行定量评价,结合GIS软件绘制不同土壤层次的盐碱化分布图,结果表明:渭北地区0~60 cm农田土壤盐碱化主要以轻度盐土和非碱化土为主,轻度盐土约占农田总面积的93.48%,非碱化土占总面积95.36%。各土层盐碱量从上到下逐渐增加,含盐量平均值在1.29~2.06 g/kg之间,碱化度平均值在2.92~4.93 g/kg之间。渭北地区土壤含盐量相对较高值分布在地势相对较低、地形平坦、河流湖泊密集区域,土壤含盐量较高区域主要出现在黄河、渭河、洛河三河交汇的大荔县部分区域(盐池洼周边);临渭区、富平县、蒲城县交界区域(卤泊滩周边);黄河沿岸的韩城市部分区域。土壤含盐量最高值分布在大荔盐池洼周边和蒲城卤泊滩周边。土壤碱化度较高值分布在临渭区、富平县和蒲城县交界区域(卤泊滩周边),黄河、渭河、洛河交汇的大荔县部分区域(盐池洼周边);最高值集中在临渭区、富平县和蒲城县交界区域(卤泊滩周边)。农田0~20 cm土层土壤含盐量受空间因素的影响较大,贡献率达49.22%,20~40 cm和40~60 cm土层土壤含盐量受土壤因素影响较大,贡献率分别达到48.33%和55.60%,其中起到决定性作用的是土壤质地、土壤团聚体、容重。研究区大部分区域的盐碱化概率较高,形成较严重的危害趋势。研究区矿化度、水埋深、盐含量和综合指标,满足对应阈值条件的高风险概率面积分别为5395 km2、1490km2、6249km2和6605 km2,占渭北地区总面积的比例分别为52%、14%、60%和64%。总体分析,土壤中盐含量随水埋深变浅、矿化度升高而增高,土壤盐碱化风险也随之增高。尤其是满足阈值条件下,综合三项指标得出的6605 km2盐碱化高概率发生区,要着重强化监测预警工作。通过对渭北地区农田土壤盐碱化进行分布调查、影响因素分析、趋势预测,可以有针对性地采取盐碱地改良措施,包括配套适宜的排灌设施、改良耕作管理技术、施入化学改良剂和生物改良等方式,治理改良渭北地区农田土壤盐碱化。
[Abstract]:In order to clarify the spatial distribution and main influencing factors of soil salinization in Weibei region of Shaanxi Province, and to provide decision support for rational utilization of regional cultivated land resources and improvement of low yield fields, the north of Weihe River was used to support the development of the soil salinization. Through field investigation, soil sampling and indoor analysis, the salinization data and corresponding space, soil properties and groundwater of the 0 ~ 60 cm soil layer in Weibei area were obtained through field investigation, soil sampling and laboratory analysis, with the Loess Plateau and tableland on both sides of Weibei Mountain as the research center. Crop yield data were used to quantitatively evaluate the distribution of soil salinization, and GIS software was used to map the salinization distribution of different soil levels. The results showed that the soil salinization was mainly composed of mild saline soil and non-alkaline soil, which accounted for 93.48% of the total area of farmland, and 95.36% of the total area of non-alkaline soil. The salt and alkali content of each soil layer increased gradually from top to bottom, the average salt content was between 1.29 and 2.06 g/kg, and the average alkalinity was between 2.92 ~ 4.93 g/kg. The relatively high values of soil salinity in Weibei area are distributed in the areas with relatively low topography, flat terrain, dense rivers and lakes, and high soil salinity mainly in the Yellow River and Weihe River. Some areas of Dali County where the three rivers of Luohe River meet (Yanchi Wagao periphery; Linwei District, Fuping County, Pucheng County Junction area (Haloga Beach periphery); Han City area along the Yellow River. The highest value of soil salt content was distributed around Dali Yanchi and Pucheng Halogen Beach. The higher soil alkalinity is distributed in Linwei area, the border area of Fuping County and Pucheng County (the area around Haloguotan, part of Dali County where the Huanghe River, Weihe River and Luohe River meet) (Yanchi Wagao area, the highest value is concentrated in Linwei District). Fuping County and Pucheng County junction area (halogen park beach around. The soil salt content in the soil layer of 0 ~ 20 cm was greatly affected by spatial factors, and the contribution rate was 49.22 ~ 40 cm and 40 ~ 60 cm, respectively, and the contribution rate was 48.33% and 55.60%, respectively, and the decisive effect was the soil texture. Soil aggregate, bulk density. The probability of salinization is relatively high in most areas of the study area, resulting in a more serious harm trend. In the study area, the high risk probability area of salinity, water depth, salt content and comprehensive index, meeting the corresponding threshold condition, is 5395 km ~ 2, 1490 km ~ 2, 6249 km ~ 2 and 6605 km ~ 2, respectively, accounting for 521460% and 64 km ~ 2 of the total area of Weibei area, respectively. As a whole, the salt content in the soil increases with the water depth, the salinity increases, and the risk of soil salinization increases. Especially under the condition of satisfying the threshold value, it is necessary to strengthen the monitoring and early warning work by synthesizing the high probability area of 6605 km2 salinization based on three indexes. By investigating the distribution of soil salinization in Weibei area, analyzing the influencing factors and forecasting the trend, we can take the measures of saline-alkali land improvement, including appropriate drainage and irrigation facilities, and improve tillage and management technology. Chemical modifier and biological improvement were applied to improve soil salinization in Weibei area.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S156.4

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