三峡库区农田的化肥面源污染状况研究

Non-Point Pollution from Farmland of the Three Gorges Reservoir Region

通过对三峡库区19个县市1996年至2003年化肥的施用情况调查分析,发现库区化肥施用总量(折纯量)由1996年的9.1×107kg增加到2003年的1.1×108kg,增幅为20.9%;但由于库区蓄水的影响,2003年比2002年减少了2.6×107kg。8年来,氮肥、磷肥、钾肥的年递增率分别为4.5%、6.2%和25.4%。库区化肥施用存在偏施氮肥的不合理现象,8年中氮肥、磷肥、钾肥占施用总量的比例总体上分别为73.6%、21.0%、5.4%。农田径流监测结果表明,氮肥、磷肥在土壤中的平均残留率分别为30.3%、13.2%,地面径流率分别为9.5%、5.3%,地下淋溶率分别为0.54%和0.75%。三峡库区化肥的施用对环境有潜在的污染,其中氮肥对面源污染的贡献比磷肥和钾肥多。库区19个县市农田施用氮肥和磷肥后的污染源强总体为:土壤>地表水>地下水。

Consumption of chemical fertilizers from 1996 to 2003 was investigated to point out the non - point pollution statuts in Three Gorges Reservoir Region （TGRR）. The results showed that usage of chemical fertilizer increased from 9.1 × 10^7 kg in 1996 to 1.1 × 10^8kg in 2003 with an increasing rate of 20.9%. It decreased 2.6 × 10^7kg in 2003 compared with that in 2002, because of the dam, s drowning. The annual increasing percentage of nitrogenous, phosphorus and potassium fertilizer was 4.5% , 6.2% and 25.4% , respectively. Nitrogenous fertilizer was partial used in TGRR. The consumption ratios of nitrogenous, phosphorus and potassium fertilizers in total were 73.6% , 21.0% , 5.4% , reapectively during eight years. The runoff test in farmland showed that average soil remnant rate, ground flow rate, underground eluviate rate of nitrogen and phosphorus fertilizers were 30.3% , 9.5% , 0.54% and 13.2%, 5.3%, 0.75% , respectively. These showed that the use of chemical fertilizer could lead to environment pollution, and the contribution of nitrogenous fertilizer to non - point pollution was bigger than that of phosphorus and potassium fertilizers in TGRR. The sequence in pollution intensity of nitrogen and phosphorus used of chemical fertilizers in 19 cities or counties of the TGRR was soil 〉 surface water 〉 ground water.