| Along with the developmont of country and agricultural modernize, the problem of water eutrophication in South of China is become serious, its representation is that TN and TP in water is high. Many researchs make clear that nitrogen losing is one of the reasons why water eutrophication in South of China, and nitrogen loss by runoff possess a big proportion.This text research of surface water TN dynamic change on the condition of different levels of fertilization,different modes of fertilization and other agriculture measure by potted plant test,field test and exactness control simulate test. Get the result of the rule that the dynamic change of surface water TN after feitilizatio, and fitting the rule.Built on the former of lose by rainfall- runoff-lose of TN. Make sure of parameter from the experiment date and then research the point of rainfall and water runoff,lose of TN simulate with the precipitation date from 1951 to 2007 with self-plait formality. Simulate the date of different growth time of rice by the former of lose by rainfall- runoff-lose of TN, analyze the rule of nitrogen lose by runoff, search the consideration and way to control nitrogen lose by runoff.The primary conclusion is that:1,dynamic change of TN on surface water with different measureTN on surface water is snap depress, and descend to a low level 7-9 days after fertilization. The downtrend can be fitting by stair reactivity equation(y=C0×ekt) , the result is that except CK and some disposes other results reach markedness level by fitting, a majority reach damned markedness.The fertilization level and the TN on surface water is positive correlativity, the fertilization mode has a big affect on TN on surface water, TN on surface water would depress with the deeper of fertilization deepness; different kind of fertilization has affect on TN on surface water, the consistence would reach the biggest by employ complex fat, it would get the least by employ complex fat+ ammonium bicarbonate; organic fertilizer has little contribute to the content of TN; the content by disposal of sandy soil is bigger than the disposal of loam, because that the adsorb ability of sandy soil is weak; with the hoist of temperature, the content of TN on surface water has a tide of depress.The content of TN have a high level 9 days after employ radical fat because of that there is no leakage of TN in the disposal of potted plant, so it has a additive effect to the content of TN of tillering fertilizer; the otherness is minish on field condition because that the effect of environment and the one another effect of different section.2,evaluate of runoff loss of rice field nitrogen in NanjingHaving 57 times of simulate experiment for insert rice on June , the result is that on the insert condition,the gross of nitrogen by runoff loss is 24.2 kg/hm2,the rate of runoff lose is 9%, which is inosculate with forward research.The simulate result shows that the relationship between rainfall and runoff amount has a damned marked diversity, but some years the relationship between rainfall and runoff amount have a very warp. The relationship between rainfall and TN runoff amount is the same with those two indexs, though they have a good pertinence, but some years have a big departure.Except rainfall,runoff,fertilization amount and kinds of fertilization, the alternation of the date of force runoff appear and fertilization would effect runoff of TN on rice field. Force runoff appear 7days after fertilization,if we can control the TN cunoff on this date, wo could abstain force runoff appearment.3,risk research of different insert time runoff of riceAfter Statistic the simulation of 30 disposals from June 1 to June 30, the date of fertilization has a big effect to the runoff of TN, with the delay of insent time, the amount of runoff has a trend of raise. The amont of runoff is small from Jun 1 to June 10 in Nanjing, the risk is second from June 11 to Jun 20, the risk is the biggest from June 21 to June 30.
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