摘要
本文对渤海西岸重黏质盐渍土进行土柱淋溶脱盐过程的研究,结果表明:在淋溶过程中,随着土壤含盐量的下降,在整个过程中,Na+、Cl-随土壤含盐量的下降而下降;由于土壤盐离子的初始含量和迁移能力的不同,K+、Ca2+、Mg2+、SO42-的含量随淋溶水增加而减小,在淋溶水接近土壤质量后含量稳定;而HCO3-与其它离子不同,出现随淋溶液增加而缓慢增加的趋势。随着土壤盐离子的迁移,土壤的pH值随土壤含盐量的的减小而呈现增大的趋势,从原土的8.50增加到土壤含盐量为1.6g/kg时的9.86,并在土壤含盐量小于1g/kg后又略有下降,但仍保持在一个较高的水平上。淋溶实验表明,在滨海重黏性盐渍土的淋溶改良过程中,需要注意因脱盐而造成的土壤碱性增加的现象,控制淋溶水的数量和采取其他相应的降碱措施。
In order to obtain characteristics of coastal heavily saline soil in leaching processes under controlled conditions, a method of soil column was adopted in the study. Different amount of water was used in the soil column experiment to leach salt from the saline soil. For increasing the experiment efficiency and simulating the outdoor soil structure, the experiment was carried out under the conditions of air-drying and absence of crushing of soil. Certain reeds were put into the saline soil to make the density of the experimental soil similar to that of the outdoor soil, which could make water horizontally go through the soil columns to accelerate the experimental processes. The experiments on indoor imitating processes of soil column leaching for desaltification were conducted on heavily saline soil over the west of the Bohai Bay coast. The results showed that in the leaching process, with decreases in soil salinity, the amount of Na^＋ and Cl^-, the primary contents of the soil salt, would decrease during the whole process whereas the amount of K^＋, Ca^2＋, Mg^2＋ and SO4^2-, the subordinate contents of the soil salinity, would decrease with increases in the amount of leaching water due to the initial concentration of salt ions and varied migration ability. However, their amount would be steady when the quality of the leaching water approached the quality of the soil. The amount of HCO3- would increase slowly with increases in the amount of the leaching water. With the migration of soil salt ions, the soil pH values would increase progressively. The pH values would increase from 8.50 initially to 9.86 when the soil salinity decreased to 1.6g/kg. The pH values of the soil would decrease slowly when the soil salinity reduced to 1g/kg. The study showed that soil alkalization could be caused by desalination when the saline soil was ameliorated to certain degree. As such, measures should be taken to decrease the soil alkalization and the amount of the leaching water should be controlled as well. The leaching water was found to be a leading factor affecting soil alkalization. Due to the lack of groundwater in the east of Hebei province near the Bohai Bay, water from deep wells have become a primary water source for drinking and irrigation. The deep groundwater is generally considered high in alkaline and contains higher amount of fluoride; hence the long-term utilization of groundwater for drinking and irrigation would result in a series of adverse effects on the health of people and soil. It is suggested that utilization of sea ice water be a promising alternative to substitute groundwater in the future because of its neutral quality, low fluoride and huge amount.
出处
《资源科学》
CSSCI
CSCD
北大核心
2010年第3期448-451,共4页
Resources Science
基金
国家"863"计划重点项目课题(编号:2006AA100206)
国家科技支撑计划重大项目课题(编号:2006BAB03A03)
国家自然科学基金项目(编号:40801230
30870467)
关键词
滨海
重黏质盐渍土
淋溶
盐分
碱分
Heavy viscosity saline soil
Leaching
Salinity
Alkaline
Marina
