【作者】 赵小波；

【导师】 夏建国；

【作者基本信息】 四川农业大学 ， 自然地理学， 2011， 硕士

【摘要】 根据1982汉源土壤普查资料和瀑布沟水电站消落区水位涨落形式,采集园地、旱地和水田利用方式下紫色土和冲积土耕作层(0-20cm)共18个样点,对三种不同土地利用方式下两种土壤类型进行土壤氮的等温吸附解吸研究,并在此基础上通过两次淹水期不同时间段对上覆水三氮(TN、氨氮、硝氮)的动态监测,研究吸附不同含量氮素的上壤淹水后向水体释放氮的特性及环境影响因素。研究结果分述如下。瀑电库区消落区不同土壤类型具有等温吸附和解吸特性。消落区821-841m高程带内园地、旱地、水田利用方式下的紫色上和冲积土对氮具有等温吸附特性,6种供试土壤的等温吸附曲线均能很好的拟合langmiur方程,且相关性较高,在0.9729-0.9971之间；淹水一落干后的6种供试土壤的吸附能力大于未淹水一落干上壤的吸附能力,循环淹水一落干后的供试上壤吸附能力与淹水一落干上壤的吸附能力差异不大。吸附一定浓度氨氮后消落带园地、旱地、水田利用方式下的紫色土和冲积上同时具有解吸氨氮的能力,未淹水一落干的供试土壤解吸能力强于淹水一落干土壤和循环淹水一落干上壤。土壤吸附的氨氮含量越高,其解吸能力越强,在浓度梯度为480mg/L-640mg/L范围内,各供试土壤的单次解吸率已达到65.51%-78.96%。吸附氨氮的含量越低,解吸能力越弱,在浓度梯度为20mg/L-160mg/L范围内单次解吸率仅为26.90%-56.95%,随着解吸次数的增多,上壤解吸量越少。从添加不同肥料水平和淹水一落干一淹水两个方面研究了瀑电库区消落区不同上壤类型向水体释放氮素的能力。在一次淹水过程中,未添加肥料水平的园地紫色土释放能力强于冲积土,上覆水TN以NH4+一N为主,当添加肥料水平后,冲积土的释放能力明显强于紫色土,上覆水TN以N03--N为主；未添加肥料水平和添加肥料水平的旱地冲积土释放能力强于紫色土,上覆水TN以N03--N为主；未添加肥料水平的水田冲积上释放能力强于紫色土,添加肥料水平后,淹水初期,水田紫色上释放能力较强,淹水后期(21d后),水田冲积上的释放能力略强于紫色土,上覆水TN含量以NH4+一N为主。二次淹水过程中,未添加肥料水平的园地紫色上的释放能力强于冲积土；添加低肥料水平的园地紫色土释放强度仍高于冲积土,而添加高肥料水平时,冲积上的释放能力较大,上覆水TN浓度以NH4+-N为主；旱地紫色上的释放能力较冲积土高,上覆水TN浓度主要以NH4+-N为主；水田冲积土的释放强度逐渐体现,不仅高于水田紫色土,同时高于园地两种土壤类型和旱地两种上壤类型,上覆水TN浓度主要以NO3--N为主。水体扰动对氮的释放具有明显作用。在一二次淹水过程中,水体扰动对氮的释放具有相似规律：在淹水初期,扰动水体,土壤氮的释放明显高于静止状态,随着时间的延长,扰动水体对氮的释放影响较弱,相对于静止组来说,基本处于平衡状态,甚至出现扰动体系上覆水TN含量低于静止体系的现象。淹水条件后测定上壤鲜样的NH4+-N和NO3--N表明,土壤中NH4+-N和NO3--N的含量会发生显著的改变,各供试土壤中NO3--N在还原条件下会还原成NH4+-N,同时以不同氮形态损失。更多还原

【Abstract】 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.更多还原