松嫩平原西部稻田回归水中污染物的输出规律

Conveying Rule of Pollutants in Paddy Drainage in Western Songnen Plain

对松嫩平原西部稻田回归水中盐分及N、P的可溶态、颗粒吸附态进行了分析。结果表明,洗盐水中主要污染物浓度相比灌溉水均明显增加,特别是Na+、HCO_3^(-)等;随洗盐次数增加,洗盐排水中盐分等污染物浓度呈降低趋势,第2次洗盐排水中盐分、NO_3^(-)-N、TP、PO_4^(3-)-P浓度相比第1次分别降低了4％～50％、72％～92％、80％～98％、9％～84％;洗盐水中盐分以可溶态为主,P以悬浮态为主,N的规律不明显,且N、P的形态变化受洗盐水中悬浮颗粒物及胶体多少的影响很大;洗盐回归水中污染物含量主要取决于土壤中的含盐量,耕作历史对其影响不明显,河水灌区回归水中Na+、HCO_3^(-)一般低于井水灌区;生长季稻田回归水中污染物浓度受降雨、施肥等影响变化较大,但生长季回归水中可溶盐离子含量均明显低于泡田期。

Through analyzing the contents of NFS pollutants in drainage from paddy in the Western Songnen Plain, conclusion has been drawn that their contents, especially sodium and bicarbonate in washing water before rice seeding were increased compared with irrigative water, and pollutants contents in washing water were dropped with increase of washing times. Dissolved substance was the dominant form of major ion, suspended substance was the dominant form of total phosphorus and phosphate, but distribution of nitrogen wasn't clear. Contents of suspended matters and colloid in washing water have an important effect on the distribution of nitrogen and phosphorus. Moreover, NFS pollutants contents in washing water were principally decided by their contents in soil of cultivated layer. Tillage history has a little influence on the pollutants contents in washing water. Contents of sodium and bicarbonate in drainage from paddy irrigated by river water were lower than those irrigated by well water, and the contents of major ion in drainage in growth season were obviously lower than that in washing water. Their increase or decrease depend on precipitation and fertilizer applied.