滴灌条件下盐地碱蓬(Suaeda salsa)种植年限对盐碱地土壤盐分离子分布的影响

Effects of different planting years of Suaeda salsa on the soil ions distribution in saline-sodic soil under drip irrigation

采用时空转化的方法研究了滴灌条件下不同盐地碱蓬种植年限(0 a、1 a、2 a和3 a)对重度盐碱地土壤盐分及盐离子在0~120 cm土壤剖面的分布特征的影响,为盐地碱蓬在盐碱地中的改良利用提供理论依据。试验结果表明:滴灌种植盐地碱蓬后土壤盐分在剖面的分布发生明显变化,根区(0~40 cm)土壤含盐量随种植年限增加而下降,根底(40~120 cm)土壤则先增加后下降;Na+和Cl-因容易被水淋洗和植物选择性吸收多,根区土壤中Na+和Cl-含量随种植年限增加有显著降低,Ca2+和SO42-不易随水移动,淋洗程度低,HCO3-和Mg2+第2 a和第3 a的淋洗效果明显好于第1 a;经过3 a种植后土壤中毒害离子Na+与Cl-和在表层盐分组成中的比例下降,Ca2+比例上升,钠吸附比(SAR)值显著降低。

Soil salinization is a serious hazard of agriculture in agricultural exploitation regions of Karamay City,Xinjiang,China.The effects of different planting years on the soil ions distribution in 0-120 cm soil profile under drip irrigation were investigated by the method of time-space transformation.The results showed that the soil salt distribution in soil profile was significantly affected by planting years.The soil salinity in the upper layers(0-40 cm)of the soil was decreased gradually with the increase of planting years,while the soil salinity in the lower layer(40-120 cm)was increased first then decreased.It is easy for Na+ and Cl- to be leached and their selective uptake by the plant is abundant,and thus their contents were decreased considerably along with the increase of the planting age.The decreasing rates of the two ions in upper layer soil were all above 49% after three planting years.Since it was hard for Ca2+ and SO42- to move with water,the speed in leaching these two ions was slow.The speed in leaching Mg2+ was higher than that of Ca2+.The leaching effect of HCO-3 contents in the soil was influenced by hydrated radius,and was better in the second and the third planting years if compared with the first year.The percentage of Na+ and Cl- in salt content of upper layers was decreased while the percentage of Ca2+ was increased,and the SAR value and the soil salinity decreased significantly after three planting years.The research results pointed out that the characteristics of soil salinity and salt ions distribution in salt affected field was changed after planting Suaeda salsa under drip irrigation,the soil environment of root zone was improved which provided a good foundation in the future land use.The innovation of paper is to reveal the distribution of soil salinity and salt ions in the salt-affected field by planting Suaeda salsa under drip irrigation based on the investigation and analysis of 7 indicators for 210 soil samples.The previous researches mostly focused on the change of soil salinity and salt ions after planting halophytes,but few researches studied the characteristics of soil salinity and salt ions distribution.The result provided useful information for a seasonable reclamation of saline-sodic soil by planting Suaeda salsa.