Empirical Study On Chemical Fertilizer Non-point Source Pollution

In recent 30 years, fertilizer consumption is continuously increasing year by year in China. From 1980 to 2007, chemical fertilizer consumption rose to 332.84 kg from 86.72 kg, equals per hectare. Fertilizer consumption is about 3 times of the world average level, exceed the international safety limit of 225 kg/hm2 fertilizer used to prevent water pollution. Highly-intensive input of fertilizer, on the one hand, ensuring the sustainable and stably development of agricultural product and the safety of food product in China, on the other hand, caused ecological environment deterioration. The serious agricultural Non-Point Source (NPS) Pollution has been taken by the government and insight peoples'high attention. This article select one city in Jiangsu province as the research object, using investigation method of statistical analysis, investigation and analysis the condition of chemical fertilizer and characteristics of application in agricultural production, analysis and evaluation the possibility and reasons of fertilizer (Nitrogen) in agricultural NPS pollution effects. Based on the control technology of NPS pollution and its research progress summary, it proposed the control countermeasure and suggestion on agricultural NPS pollution. The main research results were as follows:1. The fertilizer consumption in Jiangsu was 461.72 kg/hm2, 128.88 kg/hm2 seriously higher than nation's level in the same period. The average application of the three years (2006-2008) was 316.98 kg/hm2 in a city of Jiangsu province. Although the level is lower than those in the southern part and the northern part of Jiangsu province, but exceed the international safety limit of 225 kg/hm2. Further analysis on the relation between fertilizer consumption and crop yield proved that high-intensity fertilizer input has not generated high yield. For instance, input-output ratio per unit area in northern part of Jiangsu province was the lowest, contrary to the highest in the middle part of Jiangsu province. It showed that increasing fertilizer was not only way of yield in agriculture when reached a certain fertilizer level. Severely excessive fertilizer consumption did not only reach the target of yield, but also add the possibility hidden troubles of NPS pollution in local area.2. Analysis of the fertilizer input in a city of the middle part of Jiangsu province between 2007 and 2008 showed fertilization constitution was unreasonable. N:P:K=1:0.14:0.07 in 2007, N:P:K=1:0.2:0.16 in 2008, the city's condition of heavy N application and light P, K application was relatively severe, comparing with the the national rate (1:0.5:0.4) and the average rate in Jiangsu (1:0.3:0.2). The average ratio from organic fertilizer and from chemical fertilizer was 1:3.94 in 2007, 1:3.69 in 2008, which was significantly lower in input of organic fertilizer. The disproportion of N and P, K, and the unbalance of organic and chemical fertilizer was an important problem of fertilizer application.3. Looking from the relations of fertilization and yield, the fertilizer inputs per unit area increased, while the yield per unit area had no increase. Looking from fertilizer loss, adding fertilizer could increase fertilizer loss by runoff, and reducing fertilizer could decrease fertilizer loss by runoff. When fertilizer level reached a certain level, adding fertilizer could not increase crop yield. The nutrient elements will loss in the environment if the chemical fertilizer inputs obviously exceeded uptake and utilization, which may cause the chemical fertilizer NPS pollution.4. To proceed on profit and loss analysis, 10.64 kg/667m2 nitrogen was superabundance comparing with 30.56 kg/667m2, the average input of nitrogen in whole years, and 19.92 kg/667m2, the average uptake of nitrogen in whole years. It showed that fertilizer inputs obviously exceeded uptake and utilization lead to nutrients running off, and excessive input of nitrogen may be the mainly reason that fertilizer caused NPS pollution. Through analyzing fertilization treatment, the organic fertilizer investment are few, the chemical fertilizer investment are more, the NPK constitution was unreasonable, and the organic-chemical nutrient ratio imbalance, lead to the nutrient uptake to be low. It was an important reason led to the chemical fertilizer NPS pollution.5. Comprehensive analysis of fertilizer condition, it showed that reduced the fertilizer consumption, balanced nutrient and improved fertilization technique is the way of control the chemical fertilizer NPS pollution in a city of the middle part of Jiangsu province although fertilizer inputs per unit area is the minimum rate, from its fertilization characteristic and may caused agricultural NPS pollution. However, taking comprehensive measures for protect the agricultural NPS pollution is necessary because the agricultural NPS pollution is the multi-factor complex result, and chemical fertilizer is only a factor.