| In this research,the submerged area of Danjiangkou Reservoir in Xichuan was selected as the research,field study and lab simulation were comprehensivey applied into investigating the distribution characteristics and the release influence factors of nitrogen and phosphor in soil-water interface. The research results are as follows:⑴The contents of nutritive elements all show Normal distribution in the submerged area of Danjiangkou reservoir. The NO3-N content range of topsoil (0-20cm) is from 5.8 to 77.9mg/kg, and the average is 25.02mg/kg; NH4-N is between 5.2 and 25.6mg/kg, the average is 13.53mg/kg; TN from 181.5 to 1640.6mg/kg, the average 671.92; TP between 457.9 and 1473.2 mg/kg, the average 877.3mg/kg; Organic matter from 1.7 to 45.3g/kg, the average 18.08g/kg. The content of NO3-N, NH4-N, TN, TP and Organic matter decreases from the top to the bottom of soil profiles, and it is bigger than the content of subsoil. The content of Organic matter is relatively high, and can be classified as grade I; the TN low and grade III; the TP higher than the nationwide average. The average contents of TN and TP are higher than the concentration of TN and TP in sediment, which can cause the lowest level ecological toxic effects.⑵The variation of NO3-N content is village > sediment > farmland > water fluctuating zone > woodland > paddy. The influence of land use type on the distribution of NH4-N is not remarkable. The contents of NH4-N in each land use type are nearly same but the content of woodland topsoil is relatively high; the content of TN in paddy is far bigger than other land use types, which maybe relative to the organic matter in soil. The content of TN in sediment is a little higher than other land use types for accumulation effect. The influence of land use type on TP in the soil is not too remarkable, and the average contents in farmland, village, sediment and paddy show little difference except water fluctuating zone and woodland. The influence of land use type on the organic matter in sampling sites is relatively remarkable, the content distribution is paddy > village > sediment > farmland >water fluctuating zone > woodland.⑶After the division research, the content distribution of nitrogen and phosphor in space is little affected by the distance of riverbank, the average content of nitrogen, phosphor and organic matter in the fourth division is a little higher than other division, however, the third and fifth divisions a little lower. It demonstrates that soil in submerged area is greatly affected by cropping activities.⑷The influence of land use type on the release of nitrogen and phosphor in soil-water interface is relatively low; the release of nitrogen and phosphor is remarkably affected by the concentration gradient of nutrient salts in the interstitial water between overlying water and soil-water interface. Neutral pH conditions are favorable to the release of NO3-N and NH4-N to overlying water. In contrast, the release strength of TP under neutral pH conditions is lower than the acid and alkaline conditions. The rise of temperature can promote the release of NO3-N, NH4-N and TP. The disturbance can also promote the release of NO3-N, NH4-N and TP. when the release is the biggest, the release strength decreases. Under the living circumstance of aquatic plants without algae, light shows a little influence on the release of NO3-N, NH4-N, and TP, the release strength of light group is a little higher then dodging group.
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