开垦年限对新疆岳普湖县盐渍化土壤理化特性影响

发布时间：2018-03-20 09:04

本文选题：盐分　切入点：有机质　出处：《新疆农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：土壤盐渍化是新疆农业可持续发展的主要障碍因素。本文以岳普湖县不同开垦年限盐渍化土壤为研究对象,运用空间置换时间和统计学相关的方法,探索原始荒地和开垦农田土壤特性变化规律、剖面分布特征及其影响因素。主要结果如下:(1)岳普湖县不同开垦年限农田与荒地土壤之间总盐含量差异显著,而不同开垦年限之间差异不明显,表明该区域开垦0~5a是土壤总盐快速降低期,在10a后土壤总盐基本趋于稳定。其中,研究区荒地土壤盐渍化程度达到盐土指标,而开垦农田土壤盐渍化程度则由中度盐化向非盐化过渡;原始荒地随着土层深度的增加,在0~20 cm土层深度总盐含量迅速减少,并且表层(0~10 cm)总盐含量(161.2 g/kg)占整个剖面的62.6%。开垦5年以内的农田土壤盐分在0~90 cm比下层高,而其它开垦年限土壤0~20 cm总盐低于下层,表明荒地开垦后土壤剖面盐分总体表现出“表聚—底聚—均低”的变化特征;所调查的不同乡镇开垦20a后盐分普遍降到非盐化或轻度盐化水平。(2)研究区开垦前后土壤阴离子含量最多的均是SO42-,其次是Cl-。开垦0~5a土壤为氯化物-硫酸盐盐渍化土,而开垦10a~60a农田土壤为硫酸盐盐渍化土。原始荒地阳离子含量最多的是Na+,其次是Ca2+。而开垦后的农田土壤阳离子含量最多的是Ca2+,其次是Na+;随着开垦年限的增加土壤pH总体上表现为降低的趋势,而随着土层深度的增加,则表现为先降低后增加的趋势。研究区土壤机械组成主要以砂粒和粉粒为主,其中粉粒最多(约占70%),砂粒次之(约占20%),粘粒最少(约占10%)。(3)不同开垦年限与土壤有机质具有显著差异,开垦10a有机质含量最多,原始荒地有机质含量最少,土壤有机质在开垦0~5a内以2.2 g·kg-1a-1迅速增加;不同开垦年限与土壤碱解氮具有显著差异,在新开垦5a内土壤碱解氮以7.3 mg·kg-1a-1迅速增加,并且碱解氮的变化土层主要发生在0~20 cm。开垦5a后土壤碱解氮含量保持稳定。研究结果可为南疆极端干旱区岳普湖县盐渍化土壤改良提供数据支持和新思路。
[Abstract]:Soil salinization is the main obstacle to the sustainable development of agriculture in Xinjiang. The changes of soil characteristics, profile distribution and influencing factors of the original wasteland and reclaimed farmland were explored. The main results were as follows: 1) the total salt content of farmland and wasteland soil in Yuepuhu County was significantly different from that in different years of reclamation. However, the difference between different reclamation years is not obvious, which indicates that the period of 0 ~ 5 years of reclamation in this area is the period of rapid reduction of soil total salt, and after 10 years, the total salt of soil tends to be stable, among which, the salinization degree of waste land in the study area reaches the index of salinized soil. The salinization degree of cultivated farmland changed from moderate salinization to non-salinization, and the total salt content of the original wasteland decreased rapidly with the increase of soil depth. Total salt content (161.2 g / kg) accounted for 62.6% of the total salt content in the whole section. The salt content of the farmland soil within 5 years was higher than that of the lower layer, while the total salt content of the soil in other reclamation years was lower than that in the lower layer. The results show that the salt content in soil profile after reclamation of wasteland shows the characteristics of "surface polymerization-bottom accumulation-low average" as a whole. After 20 years of reclamation in different villages and towns, the salt content generally decreased to non-salinization or light salinization level. The most anionic content of soil before and after reclamation was so _ 42-, followed by Cl-.Reclamation for 0 ~ 5a, the soil was chlorine-sulfate salinized soil. On the other hand, the cultivated farmland soil for 10 years or 60 years was sulfate salinized soil. The most cationic content in the original wasteland was Na, followed by Ca2, and the most cationic content in cultivated farmland was Ca2, followed by Na. Soil pH decreased with the increase of reclamation years, but decreased first and then increased with the increase of soil depth. The soil mechanical composition in the study area was mainly composed of sand and silt. The most of them were silt grains (about 70%), sand grains (about 20%), clay grains (about 10%), and soil organic matter content in different reclamation years (about 10%). The content of organic matter was the highest in 10 years of reclamation, and the lowest in primitive wasteland. Soil organic matter increased rapidly with 2.2 g 路kg-1a-1 within 5 years of reclamation, and there was significant difference between different reclamation years and soil alkaline hydrolyzed nitrogen, and the soil alkaline hydrolyzed nitrogen increased rapidly at 7.3 mg 路kg-1a-1 within 5 years of new reclamation. And the change of soil layer occurred mainly in 0 ~ 20 cm soil layer. After 5 years of reclamation, the soil alkaline hydrolyzed nitrogen content remained stable. The results can provide data support and new ideas for the improvement of salinized soil in Yuepu Lake County, the extreme arid region of southern Xinjiang.
【学位授予单位】：新疆农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S156.4

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