沙土不同粒级微团聚体可解吸态磷释放通量  

Releasing flux of desorption-state phosphorus from micro-aggregates with different grain sizes in sandy soil

作　　者：王而力[1] 王嗣淇[1] 郑景华[1] 

机构地区：[1]辽宁工程技术大学环境科学与工程学院,阜新123000

出　　处：《环境科学学报》2013年第9期2597-2604,共8页Acta Scientiae Circumstantiae

基　　金：辽宁省教育厅科研项目(No.20060391)~~

摘　　要：流失的水土是污染物的重要载体,为了估算随水土流失的沙土中可解吸态磷对上覆水体的影响,采用平衡解吸法研究了沙土不同粒级微团聚体可解吸态磷的释放通量.结果表明,不同粒级沙土微团体吸附态磷的解吸比例为黏粒(0.21)<粉粒(0.29)<细砂(0.60)<粗砂(0.96).主要原因有二:细粒级中腐殖质含量显著高于粗粒级;细粒级中有机质是通过可溶有机质与黏土矿物相互结合形成复合体而富集(黏粒和粉粒级微团聚体的稳结态腐殖质所占比例显著高于其它粒级).磷在稳结态和紧结态腐殖质所形成的团聚体结构中引起的团聚体结构不可逆形变是导致黏粒级(解吸比例Dr=0.21,解吸迟滞性指数TⅡ=0.47)和粉粒级(Dr=0.29,TⅡ=0.45)微团聚体磷的解吸比例降低,解吸迟滞性指数增大的根本原因.沙土黏粒和粉粒级微团聚体携载的可解吸态磷对上覆水体的释放通量可分别按(99.52±3.54)mg·kg-1和(72.48±2.62)mg·kg-1进行估算.The loss of water and soil plays a significant role in carriers of pollutant. To estimate the effect of desorption-state phosphorus on overlying water, releasing flux from desorption-state phosphorus from micro-aggregates with different grain sizes in sandy soil was investigated by batch experiments of equilibrium desorption. The results indicated that desorption ratio of sorption-state phosphorus in sandy soil could be ranked as follows： clay（0.21）silt（0.29）fine sand（0.60）coarse sand（0.96）. This could be attributed to higher humus content of fine grain size aggregate and the enriched organic matter of fine grain size aggregates by soluble organic complex combined with clay mineral （stably combined humus of clay or silt was higher than that of others）. Irreversible transformation of aggregate structure on stable combined humus and tightly combined humus fundamentally resulted in reduced desorption ratio and increased hysteresis index of clay （Dr=0.21,TⅡ=0.47） and silt （Dr=0.29,TⅡ=0.45）. The releasing flux of desorption-state phosphorus on clay and silt aggregates from sandy soil were estimated as （99.52±3.54） mg · kg-1 and （72.48±2.62） mg · kg-1, respectively.

关 键 词：沙土 微团聚体 粒级 磷 最大解吸量 解吸比例 解吸迟滞性指数 释放通量 

分 类 号：X131.3[环境科学与工程—环境科学]