Stimulation Study On Nitrogen Release At Water Fluctuation Zone Of Pu Bu Gou Hydroelectri Power Station In Hanyuan

According to the General Detailed Soil Survey date on Han Yuan in 1982 and the fluctuation of water in water fluctuation zone at Pu Bu Gou Hydroelectric power station, this experiment collected 18 spots of soil samples from plough layer(0-20cm) of purple soil and alluvial soil of garden land,dry land and paddy field.The isothermal adsorption and desorption of the soil nitrogen of two soil types under three different land utilization was studied.Based on this, dynamic monitoring on TN, ammonia nitrogen and nitrate nitrogen of the overlying water of two periods of flooding was conducted to study the characteristics and in environmental influencing factors of the N release to the water after absorbing different N contents. The results were as follows.The different types of soil in water fluctuation zone of Pu Bu Gou Hydroelectric power station had the characteristics of isothermal adsorption and desorption. In the garden land, dry land and paddy field, the purple soil and alluvial soil in 821-841 elevation of water fluctuation zone had the characteristic of isothermal adsorption of nitrogen. The isothermal adsorption curves of the 6 kinds of experiment soil were fit the Langmiur equation and had a high correlation between 0.9729-0.9971. The ability of isothermal adsorption after inundate-drain was higher than that before inundate-drain.There was no obvious difference between circulating inundate-drain and inundate-drain. After certain adsorption of ammonia nitrogen, both of the purple soil and alluvium soil under the three land utilization had the ability of desorption of ammonia nitrogen. The experimental soils which were never inundate-drain was stronger than the inundate-drain and circulating inundate-drain. The more ammonia nitrogen the soil adsorbed, the stronger the desorption would be. When the concentration was between 480mg/L-640mg/L, all of the experimental soils'single desorption rate reached 65.51%-78.96%. The lower the adsorption of ammonia nitrogen, the weaker the desorption ability would be. When the concentration was between 20mg/L-160mg/L, all of the experimental soils'single desorption rate were only 26.90%-56.95%, Along with the increase of desorption times, the soil desorption were less.This experiment studied the ability of nitrogen release into water among the different types of soils in water fluctuation zone of Pu Bu Gou Hydroelectric power station, and the research was based on three aspects:fertilization, inundate-drain-inundate and the water perturbation condition. In the process of one time flooding, the release ability of purple soil of garden land was stronger than alluvial soil;the main form of overlying water TN was NH4+-N. After increasing fertilizer level, the ability of release in alluvial soil was stronger than purple soil and the main form of overlying water TN was NO3-N. The release ability of alluvial soil of dry land which did not increase fertilizer level and increased fertilizer was stronger than purple soil, and the main form of overlying water IN was NO3-N. The release ability of alluvial soil in paddy field which never increased fertilizer level was stronger than purple soil, but after increasing fertilizer level, at the beginning of inundation, the release ability of purple soil of paddy field was strong, and at the end of inundation(21d), the release ability in alluvial soil of paddy field was stronger than purple soil; the main form of the overlying water TN was NH4+-N. The release ability of purple soil in garden land which never increased fertilizer level was stronger than alluvial soil. The release ability of purple soil in garden land which increased low fertilizer level was also stronger than alluvial soil. But when increase high fertilizer level, the release ability of alluvial soil was bigger;the main overlying water TN was NH4+-N. The release ability of purple soil was stronger than alluvial soil in day land, and the main overlying water TN was NH4+-N. Gradually, the release ability of alluvial soil in paddy field demonstrated, not only higher than purple soil in paddy field, but also higher than both of the soils in garden plot and dry land, the main overlying water IN was NO3--N.The water perturbation had effective effect on nitrogen release. At first and second inundate process, there was a similar regular pattern in nitrogen release of the water perturbation. At the beginning of inundation, obviously,the release of soil nitrogen was higher than static condition when perturbing water. With the time extension, perturbing of the water had little effect on nitrogen release. Relative to the static group, based on the balance condition, A phenomenon that the perturbation system of overlying water TN was lower than static system appeared. The NH4+-N and N03-N of the soil after inundation condition showed the content of NH4+-N and NO3-N in soil significantly changed, and the NO3-N in all of the experimental soil would turn into NH4+-N at the reducing condition and losing at the different form of nitrogen in the same time.