紫色土坡地硝态氮淋失过程研究

CORC > 成都山地灾害与环境研究所 > 中国科学院水利部成都山地灾害与环境研究所 > 成都山地所知识仓储（2009年以前）

题名	紫色土坡地硝态氮淋失过程研究
作者	汪涛
学位类别	博士
答辩日期	2007
授予单位	中国科学院水利部成都山地灾害与环境研究所
授予地点	成都
导师	朱波
关键词	紫色土坡地硝态氮淋失壤中流
其他题名	Research on nitrate leaching process from slope cropland in Purple Soil
学位专业	自然地理学
中文摘要	氮是农业生产最重要的养分限制因子，同时也是日益增长的环境污染因子。氮污染可能是仅次于气候变暖和生物多样性衰减的全球性环境威胁。其中，地下水中过多的硝酸盐能通过造成高铁血红蛋白症而影响人类健康。而农田氮素淋失是地下水硝酸盐污染的主要原因。目前，国内外关于农田氮素淋失的研究很多，但主要集中在平地，坡地氮素淋失是农田氮素淋失研究的难点，缺乏系统深入的研究。本文利用野外径流小区观测和人工模拟降雨试验，研究紫色土坡地硝态氮淋失过程，试图查明紫色土坡地硝酸盐淋失途径、通量及控制机制，探讨坡地硝态氮淋失的影响因素，为紫色土坡地化肥管理与长江上游水环境保护提供科学依据。论文主要结果与结论如下：（1）降雨是紫色土坡地硝态氮淋失的驱动因子。紫色土区雨季降雨丰富，坡地壤中流发育，壤中流占径流总量的58.25%。（2）紫色土坡地土壤硝态氮旱季在表土累积，雨季发生迁移。（3）硝态氮随壤中流迁移是紫色土坡地土壤氮素流失的主要途径。常规施肥下，紫色土坡地（7°）地表径流硝态氮流失通量为0.66 kg/hm2.a，而壤中流硝态氮流失通量达到29.87 kg/hm2.a。（4）硝态氮淋失量与降雨量之间存在明显的正相关关系，淋失量随着降雨量的增加而增加。影响紫色土坡地硝态氮淋失过程的降雨特性包括降雨强度和降雨历时，两者通过影响壤中流形成而影响坡地硝态氮的淋失过程。（5）紫色土坡地硝态氮淋失量随土层厚度的增加而减少。20 cm深度的渗漏池硝态氮淋失通量最高，达到41.46 kg/hm2.a，占当季施氮量的27.64%。40 cm深度的渗漏池硝态氮淋失通量次之，为27.13 kg/hm2.a，占当季施氮量的18.09%。60 cm深度的渗漏池最低，仅为16.00 kg/hm2.a，占当季施氮量的10.67%。（6）研究表明，与常规施肥处理相比，增施农家肥和秸秆后，硝态氮淋失量分别降低了51.63%、31.45%，说明在紫色土坡地增施农家肥和秸秆，有助于降低坡地硝态氮淋失量。与单施氮肥相比，增施磷、钾后，各处理硝态氮淋失量分别降低了19.96%、21.33%，说明在紫色土区进行平衡施肥有助于降低坡地硝态氮淋失量。(7)以坡地水量平衡过程为基础，构建紫色土坡地硝态氮淋失的经验模型。结果表明，该模型能较好的模拟紫色土坡地硝态氮淋失量。同时，应用改进的DNDC模型进行了模拟试验，结果表明，利用改进的DNDC模型对紫色土坡地硝态氮淋失量进行预测是可行的。
英文摘要	Nitrogen is the most important nutrient which could influence crop growth. But, environmental pollution could be arose by it. Nitrogen pollution could be the third major threaten to our planet after biodiversity loss and climate change. Specially, excessive nitrate of groundwater could adversely affect human health by causing methemoglobinemia. Nitrogen leaching from cropland is an important source of nitrate of groundwater. Now, there were a lot of researches on nitrogen leaching from flat cropland, however, nitrogen leaching from slope cropland is always the environmental focus and is difficult to explore because of complex hydrological pathway. So, nitrogen leaching process from slope cropland are rarely independently measured or quantified. Field experiments and observation in runoff plot with function of interflow monitoring and artificial rainfall modeling have been conducted to study nitrogen leaching process from slope cropland of purple soil from 2004 to 2006. Objectives of this research were to analyse nitrate leaching process and impacting factors,so as to find out the approach and flux of nitrate leaching. Nitrogen concentration and water leakage were measured at every rain events. Results of this research could be useful for local chemical fertilizer management and offsite water environment protection of upper reaches of Yangtize River. Results and conclusion were listed as follows: (1) Rainfall is the main driving force of nitrate leaching by forming runoff from the slope cropland in purple soil. Interflow flux was abundant accounted for 58.25% of total runoff (overland flow and interflow) in the slope cropland (with slope degree of 7°) in this region.(2) Nitrate accumulated at surface soil layer in dry season and moved in raining season.(3) Nitrogen leaching through interflow is the main approach of nitrate loss through runoff from slope cropland of purple soil. The nitrate leaching flux through interflow from slope cropland (with slope degree of 7°) is 29.87 kg N/hm2.a at usual N fertilization rate. But the nitrate loss flux through overland flow is only 0.66 kg/hm2.a.(4) The correlation between nitrate leaching flux and rainfall is significant in the slope cropland of purple soil because of more interflow flux followed by more rainfall . Nitrate leaching process could be influenced by both rain intensity and rain time. (5) Nitrate leaching increased with the decrease of soil layer in slope cropland of purple soil. Nitrate leaching flux of the lysimeter with 20cm, 40cm or 60cm soil layer was 41.46, 27.3, and 16.00 kg N/hm2.a, respectively (6) Application of manure and crop straw could reduce 51.63% and 31.45% of nitrate leaching flux through interflow compared with usual fertilization mode in these region so that, modification of fertilization mode by application of manure and crop straw could be used for mitigation nitrate leaching from slope cropland of purple soil.Application of N with P and K could reduce 21.33% of nitrate leaching flux compared with single N application. And application of N with P could reduce 19.96% of nitrate leaching flux compared with single N application. So that balance fertilization could reduce the nitrate leaching from slope cropland in purple soil.(7) Experiential model on nitrate leaching from slope cropland of purple soil is established based on the process of water balance in slope cropland. It could be concluded that nitrate leaching flux in slope cropland of purple soil could be simulated by it. Nitrate leaching flux could be also simulated by DNDC model in slope cropland of purple soil.
语种	中文
公开日期	2010-10-21
分类号	S15;S14
内容类型	学位论文
源URL	[http://ir.imde.ac.cn/handle/131551/2269]
专题	成都山地灾害与环境研究所_成都山地所知识仓储（2009年以前）成都山地灾害与环境研究所_山地表生过程与生态调控重点实验室
推荐引用方式 GB/T 7714	汪涛. 紫色土坡地硝态氮淋失过程研究[D]. 成都. 中国科学院水利部成都山地灾害与环境研究所. 2007.