黔西强石漠化区小流域营养元素流失过程研究

发布时间：2018-05-14 06:41

本文选题：喀斯特小流域 + 降雨量　；参考：《贵州大学》2017年硕士论文

【摘要】：岩溶环境下氮、磷、钾等元素的流失必然造成土地生产力的下降甚至完全丧失,土壤养分随水土流失的迁移将直接影响相关水体的生态环境,因此喀斯特石漠化系统中氮、磷等元素的输出规律尤为重要。在裂隙发育的岩溶区,关于降雨和水土流失过程元素流失研究大部分属于模拟研究,现场观测相对较少,而喀斯特地区降雨过程营养元素流失研究则更加匮乏。本研究以黔西石漠化严重的喀斯特小流域为研究对象,对降雨过程进行监测,同时分析了溶洞水和溪水小流域在不同时间和空间尺度上氮、磷等营养元素输出特征,旨在研究自然降雨过程中喀斯特小流域地表和地下二维结构营养元素的输出特征,探讨养分动态迁移及输出规律,为喀斯特流域元素输出控制因素提供理论支撑。对岩溶泉水来源的研究有利于深入了解岩溶水文系统及泉水资源的可持续利用和管理。论文的主要研究结论如下:(1)通过分析当地大气降水δ18O-δD稳定同位素,确定大气降水是岩溶泉水及小流域溪流的主要来源,且丰水期降水在水源补给中占主导地位。(2)对不同降雨类型与降雨侵蚀力R进行相关性分析发现:雨量越大,降雨侵蚀力越明显,且夏季是控制水土流失的关键阶段。(3)通常径流量较大的汇水区河流氮、磷输出量也较大,且流域氮素输出量以NO3--N为主;NO3--N在春、冬两季输出浓度较高,NH4+-N与TN年输出浓度变化趋势类似,冬季高于其他三个季节;氮素主要是以可溶态形式流失,其中以硝态氮所占比例最多,且氮素流失伴随着磷素的输出;降雨初期是氮、磷养分流失的关键时期,且氮各形态流失均与降雨量成显著正相关。(4)降雨对加大会岩溶区Ca2+、Mg2+元素的流失,且Ca2+、Mg2+流失浓度之间表现为显性正相关,即Mg2+浓度会随着Ca2+输出量的增多而增大,反之亦然;
[Abstract]:The loss of nitrogen, phosphorus, potassium and other elements in karst environment will inevitably lead to the decrease or even total loss of land productivity, and soil nutrients will directly affect the ecological environment of relevant water bodies with the migration of soil and water loss, so nitrogen in karst rocky desertification system, The output rule of phosphorus and other elements is particularly important. In the karst area where the cracks are developed, most of the studies on rainfall and soil erosion process elements loss belong to the simulation study, the field observation is relatively few, but the study of nutrient element loss in karst area is even more scarce. In this study, a karst watershed with severe rocky desertification in western Guizhou was used to monitor the rainfall process, and the characteristics of nitrogen, phosphorus and other nutrient elements were analyzed at different time and spatial scales. The purpose of this paper is to study the output characteristics of nutrient elements in surface and underground structures of karst small watershed during natural rainfall, to discuss the dynamic transfer and output of nutrients, and to provide theoretical support for the controlling factors of element output in karst watershed. The study on the source of karst spring water is helpful to understand the karst hydrological system and the sustainable utilization and management of spring water resources. The main conclusions of this paper are as follows: (1) by analyzing the stable isotope of 未 18O- 未 D in local atmospheric precipitation, it is determined that precipitation is the main source of karst spring water and small watershed streams. The correlation analysis of different rainfall types and rainfall erosivity R shows that the greater the rainfall, the more obvious the rainfall erosivity. And summer is the key stage of controlling soil and water loss.) generally, river nitrogen and phosphorus output are larger in catchment areas with large runoff, and NO3--N is the main nitrogen output in spring. The annual output concentration of NH4-N in winter is similar to that of TN, and it is higher in winter than in the other three seasons, the nitrogen loss is mainly in the form of soluble form, in which nitrate is the most important, and the loss of nitrogen is accompanied by the output of phosphorus. The loss of nitrogen and phosphorus was the key period of nitrogen and phosphorus loss, and the loss of all forms of nitrogen was positively correlated with the rainfall. (4) the loss of Ca2 mg 2 in karst area was significantly correlated with rainfall, and the concentration of Ca2 mg 2 was positively correlated with the loss of N and P, and there was a significant positive correlation between the loss of N and P and the loss of mg 2. That is, the concentration of Mg2 increases with the increase of Ca2 output, and vice versa.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157

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