The Simulation Experiment Study Of Nitrogen And Phosphorus Migration Of Farmland In Little Zhegaohe

Agricultural non-point source pollution is already an important cause of eutrophication. Relying on the national project of water pollution control and management (2008ZX07103-002-005),the paper chooses paddy soil, upland soil and vegetable soil in typical watershed in Chaohu lake basin, little Zhegaohe watershed, as the research odject to analyze the rule of nutrient loss.Adopted indoor simulated rainfall method, the experiments set three rainfall intensities and two fertilizer levels to measure nitrogen and phosphorus content in soil and water and analyze the distribution feature and loss rule in order to provide theoretical basis of scientific agriculture management and control non-point pollution.The background values of nutrient in soil and water were measured. Ammonium nitrogen,total nitrogen,Olsen-P,total phosphorus and orgnic matter of paddy soil was the highest, while nitrate nitrogen and average orgnic matter in vegetable soil was highest and the pH value of the upland soil was highest.The infulence of fertilizer amount was investigated. With the increase of fertilizer amount, content of ammonium nitrogen, nitrate nitrogen and total nitrogen all grew. Ammonium nitrogen was easily absorbed by soil,while nitrate nitrogen was easily lost with rainfall.Mobility of phosphorus was relatively inferior, but content of phosphorus in deeper soil increased with more fertilizer. The pH value decreased with fertilizing and decreased more greatly after adding fertilizer. The orgnic matter and CODMn both increase with fertilizing.The infulence of rainfall intensity was investigated. With the increase of rainfall intensity, content of ammonium nitrogen, nitrate nitrogen and total nitrogen in soil decreased while ammonium nitrogen and nitrate nitrogen in water increased.Olsen-P in both solid and liquild phase increased; total phosphorus accumulated mainly on the surface layer; the orgnic matter increased first and then decreased; CODMn decreased.The rule of nitrient content changed with soil depth was studied. With deeper soil layer, content of ammonium nitrogen, nitrate nitrogen, total nitrogen, Olsen-P, total phosphorus and orgnic matter all decreased, meanwhile the pH value increased. The CODMn in leachate was generally higher than that in through flow.The feature of nitrogen and phosphorus loss amount was quested. It's found that ammonium nitrogen, nitrate nitrogen, total nitrogen, Olsen-P, total phosphorus loss amount correlated with fertilizer amount and rainfall intensity. The linear correlation coefficient between loss amount of nitrate nitrogen in soil and rainfall intensity is above 0.96. The total nitrogen loss amount notably increased with added fertilizer amount, and surpassed the corresponding multiple of added fertilizer amount.At last the outlook of future research is proposed:non-point pollution database and model should be established through actual field test combined with field runoff and drain; pollution load should be calculated to determine keypoint reducing object and degree; economic,policy and engineering measures advice should be put forward.