Research On Effect Of Fe On The Transportation And Transition Of Nitrogen In Zone Of Aeration And Mass Balance Model

Nitrogen in soil is not only the terraneous plants's main nitrogen nourishment supply fountain, but also a very important nitrogen exist form in biosphere. In soil and groundwater there are four nitrogen's exist form: organic nitrogen, ammonia, nitrate and gaseity nitrogen. In soil there are many nitrogen's transition route, these diversified route are also contact and effect each other. This thesis main consider nitrogen's adsorption, nitration, denitrification, mineralization. Fe as a familiar metal element in soil and groundwater, is a familiar changed valence element, it's exist form in soil and water is multifarious, and in different acid and alkalescence or oxidation and deoxidize condition diversified forms can transit each other, thus change nitrogen's exist form. This thesis select Fe as an effect factor to nitrogen'transportation and transition, qualitatively study different chroma'Fe to find their effects on nitrogen transition in different soil texture and different soil layer, and use black-box theory set a mass balance model.The experiment consists of there parts: effect of Fe on nitrogen transition in different soil texture, effect of Fe on nitrogen transition in different soil layer, static state simulate experiment, eluviate experiment.Effect of Fe on nitrogen transition in different soil texture's experiment select sand and farm, experiment find due to texture mucosity soil have more denitrification active, nitrogen in sand is more than farm, Fe accelerate nitration, increase nitrite's amount. Chroma of Fe'accretion have little effect on nitrate, effect trend of Fe on nitrite is accretion, effect trend of Fe on ammonia is minish. Effect of Fe on nitrogen transition in different soil layer's experiment select 0～20cm,20～30cm,30～50cm farm soil. Every layer's organic matter content and ventilate character is different, 0～20cm layer's ventilate is the best, have the least denitrification active, nitrate's content is the most; 20～30cm layer's have the most organic matter, adsorption action to ammonia is the strongest, and because of the bad ventilate, little nitration active make ammonia'chroma retain high, so 20～30cm layer's have the most ammonia. static state simulate experiment fill farm soil according to fill pillar's volume scale, in a week every day get sample to mensurate, experiment find because of adsorption, nitration, denitrification, mineralization happen synchronization, three species nitrogens'chroma change everyday. Nitrate have little change with time's increase, nitrite reduce with time's increase, ammonia increase first then reduce with time's increase. Fe have little effet to nitrate and nitrite, the effect trend to ammonia is reduce. Set simultaneous equations and calculate K, get the collectivity reaction trend in liquor are identical with experiment.Eluviate experiment use different chroma of Fe eluviate six days, get sample to mensurate everyday. Because of different chroma of Fe and different flux sample's three species nitrogens's migration quantity and chroma have big differentiate. set a mass balance model, and validate the model, get a good result, it's explain mass balance model almost embody the change of nitrogen in system, its apply to forecast nitrogen pollution in unsaturated zone.