基于遥感技术的河套灌区典型灌域盐分运移研究

发布时间：2018-05-20 04:28

本文选题：河套灌区 + 遥感　；参考：《西北农林科技大学》2017年硕士论文

【摘要】：内蒙古河套灌区属于干旱半干旱地区,农业的发展主要依赖于引黄灌溉,而近年来灌区农业灌溉的发展面临着许多问题。在相当长的一段时间内,相对缺水和盐渍化是制约河套灌区可持续发展的两大因素。每年通过引黄灌溉等途径,约有170万吨的盐分滞留在灌区内,但是近年来耕地土壤盐分没有明显变化,盐荒地面积并没有逐年增加。那么,流入灌区的盐分到底去了哪里,不同种类的离子各有什么运移规律,耕地的盐分又如何变化是当前亟待厘清的关键问题。前人对河套灌区的水盐平衡进行了大量的研究,但大多都忽略了作物携带的盐分在区域盐分运移当中的作用。此外,由于不同作物携带盐分能力的不同,需要对区域内不同作物的种植面积进行划分,据此计算出由作物带走的盐分。本文以河套灌区典型灌域为例,结合高分辨率的World View遥感卫星影像和实测数据实现对土地利用类型的划分,对研究区内影响盐分运移的各个主要因素进行研究,分析不同盐分的来源与排出特征,得到以下结果:(1)利用遥感卫星影像将研究区内土地分为玉米、葵花和非种植区三种主要利用类型,对2011年、2013年、2014年3个年份的分类结果进行分类统计和精度评价。结果显示,从2011年到2014年的4年间,研究区内非种植区的占地面积从34%降低到24%,年平均降幅为2.5%。因此,每年都有更多的土地投入到农业生产中。对3个年份基于实地调研的高分辨卫星影像的分类结果分别进行了精度评价,其总体精度分别为93.9%、96.4%和95.9%,Kappa系数分别为0.90、0.94和0.94。说明利用高分辨率的遥感影像结合实地调查可以更加准确地对乡镇尺度的区域土地利用类型进行划分,使量化区域内不同作物携带的盐分和衡量作物携盐对盐分运移的贡献大小成为了可能。(2)对影响河套灌区典型灌域盐分平衡的因素(灌溉、降水、作物携盐以及地下水等)进行分析研究。通过引黄灌溉,共有512.97万m3的灌溉水带来了约2667.44吨的盐分,是区域盐分的最大来源。降水年内分布极不均匀且总降水量十分稀少,带来的阳离子总量约为35.50吨。2014年,研究区内玉米种植面积为13.22km2,收获时携带的盐分为705.95吨;葵花的种植面积为7.21km2,收获时携带的盐分为228.56吨。作物携带盐分总量约为934.51吨,是引黄灌溉输入盐分总量的35%,对区域排盐起到了不可忽略的重要作用。(3)灌溉水中的盐分在土壤剖面迁移过程中发生了再分配,总体表现为非饱和区主要集聚Ca2+、SO42-,地下水中主要以Cl-、SO42-和Na+为主。本研究研究的主要创新点在于:以河套灌区典型灌域为例,基于高分辨率遥感卫星影像对区域作物种植类型分类并对种植面积进行计算,结合灌溉、降水、地下水等其他影响盐分运移的因素,分析区域盐分动态,对灌区科学调整种植结构发展农业经济具有重要的现实意义,为进一步的河套灌区节水灌溉和土壤盐渍化研究提供了科学依据。
[Abstract]:The Inner Mongolia Hetao irrigation area belongs to the arid and semi-arid area. The development of agriculture mainly depends on the irrigation of the Yellow River. In recent years, the development of agricultural irrigation in the irrigation area is facing many problems. In a long period of time, the relative water shortage and salinization are the two factors restricting the sustainable development of the river irrigation area. There are 1 million 700 thousand tons of salt in the irrigation area, but in recent years, the salt of cultivated land has not changed obviously, the area of salt wasteland has not increased year by year. Water and salt balance in Hetao irrigation area has been studied in a large amount, but most of the effects of salt in regional salt migration are ignored. In addition, the planting area of different crops in the region should be divided because of the different salt capacity of different crops. According to this, the salt of crops carried away is calculated. The typical irrigation area of the irrigation area is taken as an example, combining the high resolution World View remote sensing satellite image and the measured data to divide the land use types, study the main factors affecting the salt migration in the study area, analyze the source and discharge characteristics of different salt, and get the results: (1) using remote sensing satellite image to study the area The land is divided into three main types of corn, sunflower and non planting area. The classification results of the 3 years in 2011, 2013 and 2014 are classified and evaluated. The results show that the area of the non planting area in the study area decreased from 34% to 24% from 2011 to 2014, and the average annual decline is 2.5%., so there are more than one year. A lot of land was put into agricultural production. The accuracy of the classification results of high resolution satellite images based on field investigation in 3 years was evaluated respectively. The overall accuracy was 93.9%, 96.4% and 95.9% respectively. The Kappa coefficients were 0.90,0.94 and 0.94., respectively, which showed that the high resolution remote sensing image combined with the field investigation could be more accurate. The classification of land use types in the village and township scale makes it possible to make the contribution of salt to different crops in the quantified region and to measure the contribution of salt carrying salt to salt transport. (2) analysis and Research on the factors (irrigation, precipitation, salt carrying and groundwater) affecting the salt balance in the typical irrigation area of the Hetao irrigation area. Irrigation, with a total of 5 million 129 thousand and 700 m3 of irrigated water, brought about 2667.44 tons of salt, the largest source of regional salinity. In the year of precipitation, the distribution is very uneven and the total precipitation is very scarce. The total amount of cations brought about is about 35.50 tons.2014 years. The maize planting area in the study area is 13.22km2, the salt of the harvest is 705.95 tons; the sunflower planting is planted. The area is 7.21km2, with 228.56 tons of salt carried at the harvest. The total amount of salt in the crop is about 934.51 tons, which is 35% of the total input salt of the irrigated Yellow River. It plays an important role in the regional salt drainage. (3) the salinity of the water in the irrigation water redistributed in the process of soil profile migration, and the overall performance is that the unsaturated zone mainly concentrated on the C. A2+, SO42-, and groundwater are mainly Cl-, SO42- and Na+. The main innovation of this study is: Taking the typical irrigation area of Hetao irrigation area as an example, based on the classification of regional crop planting types and calculation of planting area based on high resolution remote sensing satellite images, combined with other factors affecting salt migration, such as irrigation, precipitation, and groundwater, and so on. The regional salinity dynamics is of great practical significance to the scientific adjustment of the planting structure and the development of agricultural economy in the irrigation area. It provides a scientific basis for the further study of water saving irrigation and soil salinization in the Hetao irrigation 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】：S274;S156.4;S127

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