上海地区氮素湿沉降及其对农业生态系统的影响

Nitrogen in wet deposition in Shanghai area and its effects on agriculture ecosystem

试验研究上海地区N素湿沉降及其对农业生态系统的影响结果表明,上海地区湿沉降中N营养盐含量较高,其中NO3-为2.587mg/L,NH4+达2.155mg/L,TIN的含量均在4.000mg/L以上。湿沉降输入到上海地区农业生态系统N营养盐的年通量较高,其中NH4+平均为26.580kg/hm2,1999年达到38.930kg/hm2;NO3-平均为31.545kg/hm2;TIN平均为58.123kg/hm2,相当于124.549kg/hm2尿素或327.980kg/hm2碳酸氢铵,1999年TIN输入量为77.750kg/hm2,相当于166.607kg/hm2尿素或438.732kg/hm2碳酸氢铵,占1998年全国化肥(N)平均施用量的35%。湿沉降中N的输入对农业生产有重要影响。

N is the necessary nutrition for plant growth and NH4^＋ , NO3^- are two major forms when N is absorbed by plants. NH4^＋ and NO3^- in wet deposition are two very important factors to compensate the N loss of agricultural ecosystem. In order to learn the situation of N in the wet deposition of Shanghai District and its effects on agricultural ecosystem in this area, the amount, forms and ecological effects of N in the wet deposition were studied. Results show that in recent years, the content of N nutrition in the precipitation is fairly high in the region, among which NO3^- is 2. 587mg/L, NH4^＋ 2.155mg/L and TIN more than 4.000mg/L. The N imported to the agriculture ecosystem of the area by wet deposition is abundant, with 26.580kg/hm^2 ·a NH4^＋ . In 1999, NH4^＋ was 38.930kg/hm^2, NO3^- was 31.545kg/hm^2, The average annual TIN imported from wet deposition is 58.123kg/hm^2· a equal to 124.549kg/hm^2 ·a CO（NH2）2 or 327.980kg/hm^2·a NH4HCO3 and in 1999 the quantity of TIN was 77.750kg/hm^2 equal to 166.607kg/hm^2 CO（NH2）2 or 438.732kg/hm^2 NH4HCO3, accouting for 35 96 of the national average application amount of fertilizer（N） in 1998.