荒漠绿洲农田盐渍化过程中的水盐动态

Water and Salt Dynamics in Farmland Salinization in Arid Oasis

以空间代替时间的方法,在干旱绿洲区选择大麦和苜蓿2种作物不同盐渍化阶段农田,并以非盐渍化农田作为对照,研究盐渍化过程中的水盐动态。结果表明:(1)不同盐渍化阶段的农田土壤含水量随土壤深度的变化有所不同,并且在大麦地10-40cm和80-100cm土层,苜蓿地20-120cm土层不同阶段农田间土壤含水量的差异显著性不同。在季节变化上,非盐渍化农田土壤含水量的变异显著高于盐渍化农田。(2)随着盐渍化程度的加剧,土壤电导率的峰值逐渐向上层移动;不同盐渍化阶段农田土壤电导率的垂直变化不同。在季节变化上,非盐渍化农田剖面电导率的变异要明显于其他盐渍化农田。(3)沿盐渍化梯度的增加,土壤中Na++K+含量表现为逐渐增加和表聚。(4)分析表明,盐渍化农田土壤水盐动态与作物生长状况、地下水电导率和土温有显著的相关性(P<0.05)。

By using the method of replacing time with space, water and salt dynamics in farmland salinization （from non-saline, to slightly, moderately, severely and to the abandoned field） were investigated in an arid oasis in northern China. Results showed that： （1） Soil water content in different salinization gradient farmlands showed different changes with the increase of soil depth. In the depth of 10--40 cm, 80--100 cm in barley farmland and 20--120 cm in alfalfa farmland, soil water content was significantly different between some salinization gradient fields（P〈0.05）. In non-saline field, variation of soil moisture was significant in different seasons than other salinization gradient fields. （2）The peak of average soil ECp gradually moved to the surface of soil layer, and different salinization gradient farmlands had different vertical changes of soil ECp. In non-saline field, variation of soil ECp was significant in different seasons than other salinization gradient fields. （3）Na- ＋ K＋ value in soil profile significantly increased along salinization gradients and gradually accumulated in the surface of soil layers. （4）Analysis showed that crop growth status, underground water salinity（EC） and soil temperature had significant correlation with dynamics of water and salt in soil profile （P〈0.05）.