不同施肥下稻田土壤胶体磷的释放及运移规律

发布时间：2018-07-08 21:09

本文选题：施肥 + 稻田　；参考：《浙江大学》2015年硕士论文

【摘要】：胶体磷是磷素赋存的重要形态,广泛存在于多种环境介质中。土壤胶体磷是土壤磷库的重要构成部分,受到土壤理化性质、施肥、降雨、植被根系等多种因素影响。本文收集查阅了有关土壤胶体磷的文献资料,并对土壤胶体磷的释放及影响因素进行归纳总结。通过田间试验开展胶体磷在稻田生态系统内的赋存、释放、迁移、变化规律研究。对比分析不同施肥处理下稻田田面水中磷素粒径组成,无机磷与有机磷含量变化。探究稻田排水中胶体态元素的含量特征及相互关系,各粒级磷的活性强度。研究施肥对土壤剖面全磷、水提取态胶体释放量、胶体磷与溶解态磷含量的影响。通过此研究全面认识稻田系统环境中土壤胶体磷的释放及运移情况,主要得到以下结论：1.施肥促使稻田田面水总磷浓度迅速达到峰值,在第一周下降最快,后期稳定在0.12mg P/L以下；稻田田面水前期以溶解态磷形式为主,后期颗粒态磷占主要,胶体磷约占总磷的7%～18%,相对稳定存在,而有机肥施用增加了颗粒态磷和胶体态磷的比重；胶体磷含量小,且受施肥、吸附作用等因素影响,胶体无机磷及有机磷构成不稳定；利用拟合曲线可有效预测田面水中磷负荷的变化。2.稻田径流磷流失受施肥、降雨影响,颗粒态磷占到了总磷的50%以上,胶体磷浓度最低,一般在0.01～0.02 mg P/L之间；有机肥的施用分别增加了颗粒态磷6.0%和胶体磷29.4%的输出；胶体磷、胶体铁、胶体铝、胶体总有机碳之间存在一定的正相关性；各粒级磷活性强度为：颗粒态磷胶体磷溶解态磷。3.施肥对土壤磷含量的影响主要集中在0-30 cm的土层,长期过量施肥容易造成土壤磷素积累,增加磷素流失风险；土壤胶体释放量随土壤深度的增加而增加,有机肥处理下胶体释放量增加,而水稻淹水处理使土壤上层胶体释放量显著减少；土壤胶体磷含量约占全磷的0.1%～2.0%,但在土壤胶体溶液(1μm)总磷中占85%以上,有机肥对胶体磷的影响较无机肥显著；水稻种植前后剖面土壤胶体释放量和胶体磷的变化,表明了淹水处理下胶体磷可能存在的纵向迁移；油菜收割后的土壤剖面胶体磷以无机磷为主,水稻收割后各施肥处理表层土壤胶体磷中无机磷和有机磷之间并无差异,溶解态磷随施肥量的增加而增加。
[Abstract]:Colloidal phosphorus is an important form of phosphorus, which widely exists in many environmental media. Soil colloidal phosphorus is an important component of soil phosphorus pool, which is affected by soil physical and chemical properties, fertilization, rainfall, vegetation roots and other factors. In this paper, the literature about soil colloidal phosphorus was collected and reviewed, and the release of soil colloidal phosphorus and its influencing factors were summarized. Through field experiments, the occurrence, release, migration and variation of colloidal phosphorus in paddy ecosystem were studied. The changes of P particle size composition, inorganic phosphorus and organophosphorus contents in paddy field surface water under different fertilization treatments were compared and analyzed. The content and relationship of colloidal elements in paddy drainage and the activity intensity of phosphorus in each grain were studied. The effects of fertilization on total phosphorus in soil profile, the amount of colloid released from water extract, and the contents of colloidal phosphorus and dissolved phosphorus were studied. Through this study, the release and transport of soil colloidal phosphorus in paddy system environment were fully understood, and the following conclusions were obtained: 1. Fertilization promoted the concentration of total phosphorus in the surface water of paddy field to reach the peak rapidly, which decreased fastest in the first week, and stabilized below 0.12mg P / L in the later stage, and dissolved phosphorus was the main form in the early stage of rice field surface water, and the granular phosphorus was the main one in the later stage. Colloidal phosphorus accounts for about 718% of total phosphorus, which is relatively stable, while organic fertilizer application increases the proportion of granular phosphorus and colloidal phosphorus, colloidal phosphorus content is small, and affected by fertilization, adsorption and other factors, colloidal inorganic phosphorus and organic phosphorus constitute unstable. The fitting curve can be used to predict the change of phosphorus load in surface water. The loss of phosphorus in runoff was affected by fertilization and rainfall, the particle phosphorus accounted for more than 50% of total phosphorus, and the concentration of colloidal phosphorus was the lowest, generally in the range of 0.01 ~ 0.02 mg P / L. the application of organic fertilizer increased the output of particulate phosphorus by 6.0% and colloidal phosphorus by 29.4%, respectively. There was a positive correlation among colloidal phosphorus, colloidal iron, colloidal aluminum and total colloidal organic carbon. The effect of fertilization on soil phosphorus content was mainly concentrated in the soil layer of 0-30 cm. Long-term excessive fertilization would easily lead to the accumulation of phosphorus in soil and increase the risk of phosphorus loss, and the amount of soil colloid release would increase with the increase of soil depth. Under organic fertilizer treatment, colloid release increased, but rice flooded treatment significantly decreased the colloid release, soil colloidal phosphorus accounted for about 0.1% of total phosphorus, but accounted for more than 85% of total phosphorus in soil colloid solution (1 渭 m). The effect of organic fertilizer on colloidal phosphorus was more significant than that of inorganic fertilizer, and the changes of soil colloid release and colloidal phosphorus before and after rice cultivation indicated the possible vertical migration of colloidal phosphorus under flooding treatment. Inorganic phosphorus was the main colloidal phosphorus in soil profile after rape harvest, but there was no difference between inorganic phosphorus and organic phosphorus in surface soil after rice harvest. Dissolved phosphorus increased with the increase of fertilization amount.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S511;S153.6

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