不同灌溉方式棉田土壤含盐量的分布特征——以玛纳斯河中游灌区为例

Spatial Distribution of Salt in Cotton Field under Different Irrigations:Taking the Irrigation District in Middle Reaches of Manas River as an Example

【目的】为干旱区节水灌溉和土壤盐渍化的预防提供依据。【方法】采用野外采样、实验室分析以及统计分析等方法,并基于空间换时间的研究方法,以玛纳斯河中游灌区为例,开展了灌溉方式(荒地、漫灌、滴灌)对棉田土壤盐分分布特征的研究。【结果】各灌溉方式变化过程0~40 cm及0~100 cm剖面内各层土壤含盐量分布特征大致为:荒地最高,滴灌棉田灌溉初期次之,漫灌棉田相对最低;随滴灌年限增加,土壤含盐量呈波动上升趋势;随着土层深度增加,各样地土壤含盐量大致呈现出:荒地各层土壤含盐量均比较高,漫灌棉田土壤含盐量主要集中在20~60 cm土层,0~20、60~100 cm土层相对较少,滴灌棉田各层土壤含盐量规律不明显。不同灌溉方式棉田纵剖面土壤含盐量的变异性为:荒地最低,漫灌棉田最高,而滴灌棉田变异性位于荒地和漫灌棉田之间,并且随滴灌年限增加土壤含盐量变异性呈现出1~4 a内波动减小,4~5 a间达到最小,4~5 a后波动增大的趋势;在灌溉方式变化过程中随土层深度增加各层土壤含盐量变异性呈波动下降的趋势。【结论】综上可知,不同灌溉方式以及灌溉年限的变化对棉田各层土壤含盐量及其变异性会有明显的影响。

【Objective】Poorly managed irrigations could give rise to soil salinity and this paper is to analyse the spatial distribution of salt under different irrigation in a cotton field aimed to provide guidance for water-saving irrigation without leading to salinization in arid regions.【Method】We took the middle stretch of Manas River as an example, from which we measured salt content in soil samples taken across a field under different irrigation methods.【Result】（1） Under different irrigation methods, salt contents in 0-40 cm and 0-100 cm soil were the highest in farrow land, moderate in cropland under drip irrigation, and least in field under flood irrigation; soil salt content increased as the time of the drip irrigation elapsed.（2）The vertical salt distribution varied. In farrow land, salt distributed approximately uniformly, while under flooding irrigation, the salt accumulated within 20-60 cm. There was no specific pattern for salt distribution under drip irrigation.（3）The variation coefficient of salt in soil also depended on irrigations, being highest in the flooding irrigated land and least in the farrow land, with the drip irrigated land between. Temporally, the variation coefficient decreased in the first five years then increased from Year 5 in the drip irrigated land. Vertically, the average variation coefficient decreased with increasing depth.【Conclusion】Irrigation methods had noticeable effects on soil salinity and spatiotemporal distribution of salt in the fields.