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

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 9.1×107kg in 1996 to 1.1×108kg in 2003 with an increasing rate of 20.9%.It decreased 2.6×107kg 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 soilsurface waterground water.