【作者】 景卫华；

【导师】 罗纨； 贾忠华；

【作者基本信息】 西安理工大学 ， 水文学及水资源， 2010， 博士

【摘要】 促进农业生产的稳固发展对于我国经济繁荣有着非常重要的意义,其中改造中、低产田是实现农业可持续发展及环境保护的重要举措。我国有一半以上的中低产田是由于涝渍以及盐碱危害造成的。改良这些中低产田首先需要通过农田排水措施来实现。由于含有从土壤中淋洗出的盐分以及化肥和农药等化学物,农田排水是目前农业非点源污染的主要形式。因此,如何在提高农业生产的同时,尽量减少或避免对环境的不利影响是当前科学、合理的设计和管理农田排水系统中一个迫切需要解决的关键问题。农田排水系统的运行和管理涉及到气候、土壤与农作以及区域水利条件等多种因素,对于农田排水问题的研究很难通过单纯的田间试验来完成。为此而诞生的田间水文模型利用计算机快捷的特点,将田间水文要素的理论计算有机的结合起来,能够迅速的预测出气候、土壤等因素变化条件下排水系统的反应。相关部门可以此为依据制定相应的水管理措施。本论文在回顾国内外排水研究的基础上,结合我国农田排水研究的现状,以淮北砂姜黑土区为例,根据“九五”国家科技攻关项目“农业气象灾害防御技术研究”中“农业涝渍灾害防御技术研究”专题研究的基础数据和部分成果,利用国际上广泛使用的田间水文模型-DRAINMOD,研究了项目区提高粮食生产的最佳排水系统设计与管理模式；并结合当地生产与水利设施建设的特点,分析了兼顾生态环境的水管理措施和方案,为研究区农业生产的可持续发展提供了理论依据。主要研究成果如下：(1)根据有限的试验资料现状以及模型模拟原理,在分析了利用连续序列试验数据进行模型率定方法的基础上,利用降雨发生时段内实测数据的代表性,提出了基于代表性离散数据的模型率定方法,并成功应用于淮北地区的模型参数率定；(2)根据模型对作物蒸散量计算的原理,提出了用实际作物潜在蒸散量(PETcrop)代替参考作物潜在蒸散量(PET0)作为输入上限来计算作物实际蒸散量(AET)的改进方法。对淮北地区排水系统模拟的结果显示,对于旱季作物,模型排水量与产量对PET数据精度很敏感,改进后的模拟结果与实际更为相符,所得结论更为科学可靠；(3)在模型率定和改进的基础上,利用当地气象和土壤资料进行了长序列模拟,通过分析地表排水、地下排水对产量的影响,兼顾排水系统的经济性、环境保护以及节约耕地等多目标的要求,确定了淮北砂姜黑土区可供当地水管理部门参考的排水系统优化布置方案；(4)针对研究区旱情与涝渍灾害并存的实际情况,在保留排水系统传统功能的同时,为了防止在降雨稀少时段过度排水,实现缓解旱情、节约水资源以及避免水质污染等多重目标,利用模型分析了缓解旱、涝灾害的不同水管理方案,得出了淮北地区应采取干沟控制排水与少量勤灌的补充灌溉措施相结合的农田水管理方案。可以在提高产量的同时,减少排水对环境的不利影响；(5)根据研究区农田施肥与生产管理措施,利用DRAINMOD NII模型模拟了氮素随排水流失的情况。模拟结果显示研究区氮素流失形式90%以上为地下排水中的硝态氮；相对于传统排水模式,控制排水可以削减地下排水中硝态氮43%,总氮排放量的42%以上,表明控制排水措施对于当地生态环境保护具有十分积极的意义。更多还原

【Abstract】 Enhancing stable development of agricultural production has great importance for economic prosperity of China. One of the major steps is to improve production of the low and medium yielding lands, which covers over 65% of total farmland in China. About half of the low-yield farmland is affected by water logging and salinity hazards, these lands can be initially improved through farmland drainage.Because drainage discharge contains salt and agrichemicals leached through soils, it has been recognized as the primary contributor of agricultural non-point source pollution. In order to reduce or avoid negative impact of drainage on environment while maintaining agricultural production, rational design and management of agricultural drainage system are critical issues that need to be tackled immediately.Operation and management of agricultural drainage system involve multiple factors that range from weather, soil and crops, and existing hydrologic conditions. Drainage research is hard to accomplish through field studies only. Taking advantages of fast computers, field hydrology models have been developed to predict drainage system performance under varying climatic and soil conditions by combining computation theories of field hydrological components. The model simulations results may provide guidance for relevant management sectors to work out corresponding water management measures.Based on the drainage research conducted internationally, considering current status of drainage studies in China, this dissertation presents a case study in the vertisol soil district of Huaibei Plain, China using the widely applied field hydrology model-DRAINMOD. Model testing was based on the experimental results from the national "Ninth Five-Year Plan" scientific and technological project "Agricultural meteorological disaster prevention technology research" in "agricultural water logging disaster prevention technology research". DRAINMOD was used to analyze improved drainage system design for better crop production; the model was also used to analyze drainage water management that will both enhance crop production and environmental protection. The modeling results may provide theoretical basis from sustainable development of agricultural production of the study area. Major findings of the research are as below:(1) According to limited experimental data and model simulation principle, by analyzing model testing using continuous sequence of experimental data, considering representative data collected during rainfall events, a new model calibration method was proposed using discrete data points and the procedure was successfully applied in model calibration of the study area;(2) Based on the calculation methods for crop evapotranspiration (AET) used in DRAINMOD, the potential evapotranspiration inputs were modified from reference crop (PETo) to actual crop (PETcrop). Simulation results showed that changes in PET inputs are sensitive to drainage and yield predictions for dry season crop, the improved PET inputs generated more realistic predictions and the results are more scientifically reliable.(3) Based on the calibration and improvement of the model, the optimum subsurface drainage system design was derived by long term simulation with DRAINMOD considering the multiple objectives such as profit maximization, environment protection, land economization and sustainable development etc. Optimized drainage system design schemes for the study area were presented for local water management reference;(4) For achieving the multiple objectives of eliminating drought and over drainage, saving water resources, decreasing the stress of downstream flooding and water quality degradation etc, the combination of controlled drainage at the main ditch and irrigation scheme at a frequent and small amount mode were found to be the optimum water management practices through model simulations. These practices can significantly increase crop yields and mitigate negative impact of drainage;(5) Referring to local fertilization practices of the study area, DRAINMOD NII was used to simulate nitrogen losses through subsurface drainage in the Huaibei Plain. The results showed that 90% of total nitrogen losses are the nitrate form lost with the subsurface drainage, controlled drainage at the main ditch can reduce total nitrogen losses by 42% and nitrate losses with subsurface drainage by 43%, indicating that controlled drainage has significant importance for eco-environmental protection in the Huaibei Plain.更多还原