大孔隙和优先水流及其对污染物在土壤中迁移行为的影响

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在水稻和大豆土壤中的优选迁移。

MACROPORES AND PREFERENTIAL FLOW AND THEIR EFFECTS ON POLLUTANT MIGRATION IN SOILS

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 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 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. This phenomenon of preferential migration could not be obsearved in repacked soil monolith without macropores.