摘要
本文研究了冻融和干湿交替过程对土壤大孔隙及由其导致的优先水流形成的作用，以及表面活性剂直链烷基苯磺酸盐（LAS）在水稻和大豆土壤中的优先迁移。结果表明，冻融和干湿交替均可使土壤产生大孔隙和优先水流，而且前者的作用比后者强，LAS在1．5m水稻土体和大豆土体的优先穿透时间均为23天，而优先穿透淋洗水量却相差甚大，前者为69mm，后者仅为9mm。优先迁移过程不受土壤吸附／解吸过程的制约。受土壤吸附／解吸过程制约的平衡穿透淋洗水量，水稻系统和大豆系统分别185mm和178mm，两者很为接近。在水稻和大豆土壤，LAS的优先穿透时间比平衡穿透时间分别提前了21天和35天。优先穿透峰浓度在大豆系统可达平衡穿透峰浓度的20％～30％，在水稻系统则高达30％～86％。在没有大孔隙的填充土柱中，观察不到这种优先迁移的现象。
In this paper, effects of freeze-thawing and dry-wetting processes on the formation of soil macropores and preferential flow under simulative conditions in laboratry, and preferential migration of linear alkylbenzene sulfonate (LAS) in soils growing rice and soybean in field lysimeter were studied. Results showed that both freeze--thawing and dry--wetting processes could cause macropores and preferential flow This work was funded by the National Natural Science Foundation of China (Project No. 49771044) and the Open Laboratory of Ecological Process of Trace Substance in Terrestrial Ecosystem, Institute of Applied Ecology,Chinese Academy of Sciences, to which the authors are very grateful.in soils and that the former was stronger than the latter. The duration of preferential penetration of LAS through 1.5m soil monolith was 23 days for both soils growing rice and soybean. However, their leachate volumes of preferential penetration were much different i.e., 69 mm for soil growing rice and only 9 mm for soil growing soybean. Preferential migration process was not governed by soil adsorption/desorption processes. The leachate volumes in equilibium governed by adsorption/desorption processes in soil were very similar for paddy rice (185mm) and soybean (178mm). The duration of preferential penetration of LAS was 21 and 35 days ahead of equilibium penetration for soils growing rice and soybean, respectively. The peak concentrations of preferential penetration of LAS amounted to 20%-30% of peak concentration of equilibrium penetration in soil growing soybean. This ratio was as high as 30%-- 86% in soil growing rice. iiis phenomenon of preferential migration could not be obsearved in repacked soil monolith without macropores.
出处
《土壤学报》
CAS
CSCD
北大核心
1999年第3期341-347,共7页
Acta Pedologica Sinica
基金
国家自然科学基金!49771044
中国科学院陆地生态系统痕量物质生态过程开放实验室基金
关键词
土壤
大孔隙
优先水流
冻融交替
LAS
迁移行为
Soil, Macropore, Preferential flow, Freeze--thawing process, Drywetting process, LAS, Migration
