景电灌区盐碱耕地土壤剖面盐分时空演替特征研究

Spatio-temporal succession characteristics of saline-alkali soilprofile salt in Jingdian Irrigation District

为了研究西北干旱引黄灌区长期综合改良条件下盐碱耕地土壤化学性质的时空演替特征,以甘肃省景泰川电力提灌灌区(以下称“景电灌区”)为例,采集灌区不同耕种年限(5、10、15 a)盐碱耕地0~80 cm土层土壤样品,同时选取试验地附近未耕作盐碱荒地作为对照。对土壤水溶性总盐(TS)、pH值和各盐分离子指标进行测定与分析,研究了不同耕种年限盐碱耕地土壤剖面盐分的时空演替特征。结果表明,随着耕种年限的增加盐碱耕地土壤脱盐效果明显,土壤TS由未耕种时的4.081 g·kg ^-1 下降到耕种15 a后的0.411 g·kg ^-1;而土壤pH值则随着耕种年限的增加呈现出缓慢增加趋势,由未耕种时的8.30上升至耕种15 a后的9.05,说明土壤在脱盐过程中出现了碱化趋势;其余盐分指标除HCO3^-随着耕种年限的增加呈现缓慢增加趋势,钠吸附比(SAR)、Cl^-/SO^2- 4以及其余各盐分离子均随着耕种年限的增加而降低。可见随着耕种年限的增加,土壤条件得到了很大的改善,有利于作物的生长,但长期的土壤脱盐改造同时也诱发了土壤碱化倾向。

Over a long-term comprehensive improvement of the saline-alkali land in the arid Yellow River Irrigation Districts in northwest China, the soil chemical properties have been changing temporally and spatially.The Jingtaichuan Electric Irrigation District (hereinafter referred to as “Jingdian Irrigation District”) was taken as the typical study area.The soil samples were collected from 0~80 cm layers of the selected areas on different cultivation years (5, 10, 15 a), and an uncultivated saline-alkali wasteland near the test site was selected as a control.The total soluble salts (TS), pH, and various salt ions were measured and analyzed to explore the spatio-temporal differentiation of salt in the saline-alkali soil profile.The results showed that with the extension of cultivation years, the salinity of soil profile was significantly decreasing that the TS of soil profile reduced from 4.081 g·kg ^-1 to 0.411 g·kg ^-1 with the 15a, while the pH was slowly increasing from 8.30 to 9.05 during the period.The concentration of HCO - 3 did not change much and the values of other salt ions and SAR, Cl -/SO 2- 4 were decreasing.It indicated that with the extension of cultivation years, the soil conditions had been greatly improved, which is beneficial to the crops growth.However, the long-term comprehensive improvement of the saline-alkali land resulted in the alkalization tendency of cultivated land.