Fertilizer, Pesticide Usage & Nitrate Contamination Of Groundwater In The Vegetable Cultivation Area

From December 2001 to April 2003, 290 farmers were investigated and 84-136 wells were monitored for 3 times in Quzhou county, Hebei province. The study aimed to determine the farmer-level pesticide use, fertilizer use and the extent of nitrate contamination in groundwater in a vegetable cultivation area of Quzhou County, Hebei Province. The research results are as follows:1) The fertilizer use was 1650.4 kg/hm2, and N: P: K=5 : 2 : 1. The chemical fertilizer use was 845.9 kg/hm2 N, 240.5 kg/hm2 P, and 40.3 kg/hm2 K and the use of manure was 1.9t/hm2.2) In 2002, the total pesticide use was 21.42 kg/hm2 in the vegetable cultivation, with 15.84 kg/hm2 insecticides and 5.57 kg/hm2 fungicides. In autumn, Farmers applied 14.76 kg/hm2 pesticide in their vegetables, with 11.86 kg/hm2 organophosphates, 0.84kg/hm2 cypermethrin, 0.39 kg/hm2 other types of insecticides and 1.65 kg/hm2 fungicides.3) 70 percent of the total pesticide use was insecticide use. Organophosphates contributed to 64 percent of the total pesticide use.4) 19.5% of sites surveyed had groundwater NO3--N exceeding the China potable drinking water standard in February 2003, 14.0% in April 2003, and 5.7% in October 2002. And there are considerable variations within wells between the sampling times, but further monitoring is required. Not only the concentrations of NO3--N in shallow groundwater vary considerably temporally, but also spatially.5) Nearly all the sites that exceeded the potable drinking water standard are in the riparian of Fuyang River, which have a more than 30-year vegetable-planting history. Because of this, the south vegetable cultivation area of the county is more severely polluted than that of the north. It suggests a fact that a nitrate load in the groundwater can be caused by a long time vegetable planting.6) Depth to groundwater has little effect on the groundwater NO3--N.