不同坡度及降雨强度下面源污染中磷素流失特征研究

发布时间：2018-03-22 02:31

本文选题：面源污染　切入点：磷素流失　出处：《西南交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：水体富营养化的日益加剧与农业面源污染问题中氮、磷等的排放问题密切相关。施肥结构不合理、过度且过量的施用化肥等都会使得土壤中的磷素处于富集状态。土壤中滞留的磷素会随着土壤侵蚀、地表径流和渗漏淋溶这几种方式进入地表及地下水体环境中并不断累积,最终引起水体富营养化。因此,对于面源污染中磷素流失规律的研究就显得尤为重要。本论文通过模拟耕作地块进行小白菜种植,运用人工降雨系统,进行了实验。分别测定在不同降雨强度和不同坡度条件下随地表径流水和土壤渗漏水流失的总磷、溶解态磷和颗粒态磷的浓度,总结分析其变化规律及影响因素。本论文首先研究了不同坡度条件对于土壤中磷素流失的影响。研究得出,随着地表径流水流失的总磷和颗粒态磷的浓度与坡度呈正相关;而溶解态磷浓度与坡度呈负相关。土壤20 cm渗漏水中总磷、溶解态磷,土壤40 cm渗漏水中总磷、溶解态磷和颗粒态磷浓度与坡度呈负相关。同时,研究得出,不同坡度下,总磷、溶解态磷和颗粒态磷的浓度均随着土壤层次的加深而呈现递减的分布规律。坡度较大(15°、20°)时,颗粒态磷是地表径流水中磷素流失的主要形态,坡度较小(5°、10°)时,地表径流水中溶解态磷和颗粒态磷流失程度相当。在不同坡度条件下,土壤20 cm和40 cm渗漏水中磷素流失的主要形态均为溶解态磷。然后,本论文研究了不同降雨强度条件对土壤中磷素流失的影响。研究得出,地表径流水、土壤20 cm和40 cm渗漏水中总磷、溶解态磷和颗粒态磷的浓度与降雨强度呈正相关。不同降雨强度下,随水流失的总磷、溶解态磷和颗粒态磷的浓度随着土壤层次的加深而呈现递减的分布规律。雨强较小(30 mm/h和60 mm/h)时,地表径流水中溶解态磷和颗粒态磷流失程度相当。雨强较大(90 mm/h和120 mm/h)时,随着地表径流水流失的磷素的主要形态是颗粒态磷。在不同降雨强度条件下,溶解态磷是土壤20 cm和40 cm渗漏水中总磷流失的主要形态。通过以上研究,了解了土壤中磷素在特定条件下的去向特征规律以及影响因素,这为实际生产中不同降雨强度、不同坡度地形对农村面源污染的影响研究提供了一定的理论方面的支持和指导作用。
[Abstract]:The increasing eutrophication of water body is closely related to the discharge of nitrogen and phosphorus in agricultural non-point source pollution. Excessive and excessive application of chemical fertilizers will lead to the accumulation of phosphorus in the soil, and the remaining phosphorus in the soil will enter and accumulate in the surface and underground water environment with soil erosion, surface runoff and leakage leaching. Therefore, it is very important to study the regularity of phosphorus loss in non-point source pollution. In this paper, we use artificial rainfall system to plant pakchoi on simulated tillage plots. Experiments were carried out. The concentrations of total phosphorus, dissolved phosphorus and particulate phosphorus in the topographic diameter income and soil leakage water were determined under different rainfall intensity and slope. Firstly, the effects of different slope conditions on the loss of phosphorus in soil were studied. The results showed that the total phosphorus and the concentration of particulate phosphorus were positively correlated with the slope with the loss of total phosphorus and particulate phosphorus by income. However, the concentration of dissolved phosphorus was negatively correlated with the gradient. The total phosphorus, dissolved phosphorus, total phosphorus and dissolved phosphorus and particulate phosphorus were negatively correlated with the slope degree in 20 cm soil leakage water, 40 cm soil leakage water, and 40 cm soil leakage water, respectively. At the same time, it was found that under different slopes, the concentration of dissolved phosphorus and particulate phosphorus was negatively correlated with the slope. The concentration of total phosphorus, dissolved phosphorus and particulate phosphorus decreased with the deepening of soil layer. When the slope was larger than 15 掳~ 20 掳, granular phosphorus was the main form of phosphorus loss in surface runoff water, and the slope was lower than 5 掳~ 10 掳. Under different slope conditions, the main forms of phosphorus loss in 20 cm and 40 cm soil leakage water were dissolved phosphorus. In this paper, the effects of different rainfall intensity on phosphorus loss in soil were studied. The results showed that the topsoil diameter income, soil 20 cm and 40 cm leakage water total phosphorus, The concentrations of dissolved phosphorus and particulate phosphorus were positively correlated with rainfall intensity. The concentration of dissolved phosphorus and particulate phosphorus decreased with the deepening of soil layer. When the rainfall intensity was less than 30 mm/h and 60 mm / h, the amount of dissolved phosphorus and particulate phosphorus in surface runoff water was the same as that in the surface runoff water. When the rainfall intensity was higher than 90 mm/h and 120 mm / h, the concentration of dissolved phosphorus and particulate phosphorus in surface runoff water was about 90 mm/h and 120 mm / h, respectively. Under different rainfall intensity, dissolved phosphorus is the main form of total phosphorus loss in 20 cm and 40 cm soil leakage water. The characteristics of phosphorus in soil under certain conditions and the influencing factors are understood. This is different rainfall intensity in actual production. The research on the influence of different slope topography on rural non-point source pollution provides some theoretical support and guidance.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X52

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