共查询到20条相似文献，搜索用时 109 毫秒
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Crop area planning plays significant role in agricultural water management. During the planning, because of ambiguous or uncertain information caused by the vagueness of decision makers’ subjective preference or the uncertainty of objective information, conventional multi-objective linear programming (MOLP) model is not suitable for such decision-making in such fuzzy environment. In this study, we proposed the fuzzy multi-objective linear programming (FMOLP) model with triangular fuzzy numbers and transformed the FMOLP model and its corresponding fuzzy goal programming (FGP) problem to crisp ones which can be solved by the conventional programming methods. The FMOLP model was applied to crop area planning of Liang Zhou region, Gansu province of northwest China, and then the optimal cropping patterns under different water-saving levels and satisfaction grades for water resources availability of the decision makers (DM) were obtained. Compared to the MOLP model, the FMOLP model itself expresses the fuzzy information effectively, and its solutions can represent the DMs satisfactory degree of the subjective preference and propose alternative solutions for better decision support when applied in the crop area planning. 相似文献
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A hybrid fuzzy-stochastic water-management (FSWM) model is developed for agricultural sustainability under uncertainty, based on advancement of a multistage fuzzy-stochastic quadratic programming (MFSQP) approach. In MFSQP, uncertainties presented in terms of fuzziness and randomness can be incorporated within a multilayer scenario tree, such that revised decisions are permitted in each time period based on the realized values of the uncertain events. Moreover, fuzzy quadratic terms are used in the objective function to minimize the variation of satisfaction degrees among the constraints; it allows an increased flexibility in controlling the system risk in the optimization process. Results of the case study indicate that useful solutions for the planning of agricultural water management have been obtained. In the FSWM model, a number of policies for agricultural water supply are conducted. The results obtained can help decision makers to identify desired water-allocation schemes for agricultural sustainability under uncertainty, particularly when limited water resources are available for multiple competing users. 相似文献
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A robust modeling approach for regional water management under multiple uncertainties 总被引：1，自引：0，他引：1
In regional water management systems, various uncertainties may be derived from random feature of resource conditions and natural processes, errors in estimated modeling parameters, as well as imprecision or fuzziness human-induced. This leads to difficulties in formulating and solving the resulting regional water management problems. In this study, a robust multistage interval-stochastic programming (RISP) method is developed for dealing with vague and random information in regional water management systems. The decision variables are useful for justifying and/or adjusting the decision schemes for agricultural activities through the incorporation of their implicit knowledge on regional water management. Different policies for agricultural water supply have been analyzed. The results can help to identify desired water-allocation schemes for agricultural sustainable development that the prerequisite water demand for supporting crops’ survival can be guaranteed when the water resource is scarce. 相似文献
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针对西北干旱区灌区生态环境脆弱、水资源短缺、复杂不确定性等问题,以石羊河流域红崖山灌区为例,耦合2型模糊集、模糊可信度约束规划和多目标规划等理论方法,构建了基于2型模糊集的多目标农业-生态水土资源优化配置模型。模型以灌溉水损失最小、生态植被灌溉水满意度最大、生态植被灌溉水费用最小和主要粮食作物经济效益最大为目标,对红崖山灌区10个决策单元的地表水、地下水和粮食作物种植面积进行优化配置。求解模型得到不同可信度水平和不确定性程度下的水土资源优化配置方案。结果表明：耦合2型模糊集的模型能够提供丰富的配置方案,水量对可信度水平的敏感性高于不确定性程度,作物种植结构对可信度水平不敏感。以不确定性程度参数为0.5、可信度水平为0.7时为例,生态植被均通过地表水灌溉,作物通过地表水、地下水联合灌溉,玉米的产量和经济效益均大于小麦。相比前人研究,本研究考虑生态植被灌溉需求,优化结果更加真实合理。本研究可为决策者提供较为符合灌区实际的配置方案,为西北干旱区灌区现代化建设提供科学指导。 相似文献
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Radial interval chance-constrained programming for agricultural non-point source water pollution control under uncertainty 总被引：2，自引：0，他引：2
Inherent uncertainties in agricultural non-point source water pollution control problems cause great difficulties in relevant modeling processes. A radial interval chance-constrained programming (RICCP) approach was developed in this study for supporting source-oriented non-point source pollution control under uncertainty. The proposed RICCP approach could tackle two-layer uncertainty resulting from temporal and spatial variability of many factors and their uncertain interactions. Based on the concept of radial intervals and chance-constrained programming, RICCP could reflect the randomness in the bounds of interval parameters, with or without known probability distributions. RICCP could also allow decision makers to adjust the conservativeness of solutions via protection and significance levels, helping satisfy environmental, economic and resource-conservation requirements in a holistic and interactive manner. The proposed methodology has been applied to an agricultural water pollution control case. The most-profit agricultural development strategies were explored while restricting environmental impacts to an acceptable level. A series of interval solutions for agricultural practices were generated corresponding to varied risk levels of constraint violations, which could help screen optimal alternatives according to decision makers’ profit and risk considerations as well as various system conditions. RICCP model was also compared to its alternatives. Significant differences in the solutions among the compared models further demonstrated the advantages of the proposed approach. 相似文献
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An inexact two-stage water management model for planning agricultural irrigation under uncertainty 总被引：2，自引：0，他引：2
In this study, an inexact two-stage water management (ITWM) model is developed for planning agricultural irrigation in the Zhangweinan River Basin, China. The ITWM model is derived from the incorporation of interval-parameter programming (IPP) within a two-stage stochastic programming (TSP) framework. It can reflect not only uncertainties expressed as probability distributions but also interval numbers. Moreover, it can provide an effective linkage between conflicting economic benefits and the associated penalties attributed to the violation of the predefined policies. Four decision scenarios associated with different water-resources management policies are examined. Targeted incomes, recourse costs, and net system benefits under different scenarios are analyzed, which indicates that different policies for agricultural irrigation targets correspond to different water shortages and surplus, and thus lead to varied system benefit and system-failure risk. The results are valuable for supporting the adjustment or justification of the existing irrigation patterns and identify a desired water-allocation plan for agricultural irrigation under uncertainty. 相似文献
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基于GIS的数字西江水质预警预报系统设计和应用 总被引：4，自引：0，他引：4
数字西江水质预警预报系统是一个以地理信息系统（GIS）和数据库管理系统（DBMS）为开发平台，面向管理和决策层的可视化动态信息系统，采用集成GIS组件和水量水质数值模型的耦合方式。本系统一方面建立基于GIS的水环境评价、水环境容量计算和污染物总量控制。另一方面在发生水污染突发事故后，能够快速预报污染物向下游的扩散时间、扩散面积、确定污染范围、污染程度及对下游取水口等所造成的影响，为决策部门提供决策支持。 相似文献
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【目的】揭示土地利用变化下面源污染时空变化特征,探究流域景观格局与面源污染的关系。【方法】以布尔哈通河流域为研究对象,利用SWAT分布式水文模型模拟1986-2016年4期土地利用变化下面源污染分布特征,运用Fragstats4.2软件计算了1986年和2016年布尔哈通河各子流域的景观格局指数,最后使用CANOCO5.0软件分析子流域面源污染和景观指数之间的关系。【结果】①构建的SWAT模型模拟的径流量和总磷量在校准期和验证期的决定系数R2和纳什效率系数NSE都达到0.6以上,模型能很好地模拟流域水文水质状况,1986-2016年,SWAT模拟的总磷年负荷分别为74.04、73.78、82.50 t和128.31 t。②面源污染与景观格局存在密切关系,景观组成格局方面,林地面积与总磷负荷负相关,农田和建设用地面积与总磷负荷正相关;景观空间格局方面,林地斑块破碎化程度与总磷负荷正相关,而农田斑块的破碎化程度与总磷负荷负相关。流域斑块之间的越高流通性和聚集性,对养分流失改善有积极作用,而流域内景观异质性的增加和形状的复杂化,则会导致污染负荷输出风险的增加。【结论】流域面源污染负荷急剧增加,面源污染防治的关键控制区域在坡度较高的北部区域和农田及城镇集中的东部区域,该区域规划土地利用和优化景观格局时,应优先考虑防止林地斑块破碎化程度的提高和控制城镇面源污染源。 相似文献
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《Agricultural Systems》1998,57(2):161-195
The interactive use of experimentation and modeling is an efficient way to devise and test new agricultural management systems. The Root Zone Water Quality Model (RZWQM) is a comprehensive simulation model designed to predict the hydrologic response, including potential for groundwater contamination, of alternative crop-management systems. The model is one-dimensional (vertical into the soil profile) and integrates physical, biological and chemical processes. It simulates crop development and the movement of water, nutrients and pesticides over and through the root zone for a representative unit area of an agricultural field over multiple years. RZWQM allows for a variety of management practices: tillage; irrigation, fertilizer, manure and pesticide applications; tile drainage and crop rotations. Several significant validation efforts have shown the usefulness of RZWQM for evaluating and developing management scenarios. 相似文献
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通过种植两茬油菜,设置7种施肥模式:有机肥施氮量600 kg/hm2;有机肥施氮量300 kg/hm2;无机肥施氮量767 kg/hm2;无机肥施氮量383 kg/hm2;有机肥施氮量450 kg/hm2,无机肥施氮量153 kg/hm2;有机肥施氮量300 kg/hm2,无机肥施氮量383 kg/hm2;有机肥施氮量150 kg/hm2,无机肥施氮量191 kg/hm2,研究了日光温室0～200 cm土壤中NH4+-N和NO3--N的迁移累积。结果表明,不同施肥模式主要影响0～40 cm土壤中NH4+-N的平均累积量和平均质量比,单施无机肥的相应值大于单施有机肥;不同施肥模式主要影响0～40 cm土壤中NO3--N的平均累积量和平均质量比,当施氮量小于383 kg/hm2时,相应值从大到小依次为:单施无机肥、单施有机肥、有机肥和无机肥配施,不同施肥模式也影响40～160 cm土壤中NO3--N的迁移累积。从地下水污染风险和产量考虑,北京农业种植区日光温室油菜种植可按照有机肥150 kg/hm2、无机肥191 kg/hm2的施肥模式进行施肥。 相似文献
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在农业生产中,水分和肥料是不可或缺的两大基本要素。水肥耦合将水、肥有机结合,通过二者的协同效应实现作物高产优质目的。在分析水资源紧缺和肥料施用不合理的现状基础上,回顾了水肥耦合的发展历程、定义及水肥耦合灌溉模式,阐述了水肥耦合对茄子生长形态、光合特性、产量和品质等影响的研究进展。结果表明,水肥耦合是节约水肥资源,降低环境污染,实现茄子高效优质增产的有效措施。深入探究茄子水肥耦合机制,构建多因素水肥耦合模型,寻求最佳水肥配比实现精准化灌溉,可为指导茄子合理的水肥管理并使茄子达到高效优质生长提供参考。 相似文献
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基于多目标模糊规划的灌区多水源优化配置 总被引：2，自引：0，他引：2
以黑龙江省和平灌区为例,构建基于多目标模糊规划的灌区多水源优化配置模型,该模型能够在提高农业灌溉用水净效益的同时有效减少农业灌溉水量,促进和平灌区多水源高效配置。采用具有非线性隶属度函数的模糊多目标规划求解模型,得到不同流量不同水源下的最优配水方案。结果表明:不同流量水平下水稻不同生育阶段均存在缺水现象,低流量下需从柳河水库引入外调水才能保证水稻的最小需水量。为保证灌区整体效益,按照引水工程、提水工程、井灌工程的先后顺序进行配水,并得到多目标配水模型在不同情景下的运行稳定情况。该模型可以高效地进行灌区多水源在作物各生育阶段的优化配置。 相似文献
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在对常用经济评价方法广泛研究的基础上，分析了常用评价方法在进行方案比选时存在的一些缺陷，针对这些缺陷，建立了水利工程项目综合经济评价模型。该模型在建立评价指标体系的基础上，将层次分析法和模糊数学理论结合起来，运用层次分析法确定评价指标的权重，采用模糊数学方法对各比选方案进行综合评价，得出评价结论。同时，结合水利工程的实际特点，将所建立的评价模型应用于具体的水利工程项目进行实例分析，验证了模型的正确性。结果表明，使用该模型可以使水利工程项目经济评价更全面、更科学、更符合实际，为正确的项目决策提供了可靠依据，为决策者提供了有力的参考和支持。 相似文献
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Application of the Soil and Water Assessment Tool (SWAT) to predict the impact of alternative management practices on water quality and quantity 总被引：10，自引：0，他引：10
Alternative land management practices such as conservation or no-tillage, contour farming, terraces, and buffer strips are increasingly used to reduce nonpoint source and water pollution resulting from agricultural activities. Models are useful tools to investigate effects of such management practice alternatives on the watershed level. However, there is a lack of knowledge about the sensitivity of such models to parameters used to represent these conservation practices. Knowledge about the sensitivity to these parameters would help models better simulate the effects of land management. Hence, this paper presents in the first step a sensitivity analysis for conservation management parameters (specifically tillage depth, mechanical soil mixing efficiency, biological soil mixing efficiency, curve number, Manning's roughness coefficient for overland flow, USLE support practice factor, and filter strip width) in the Soil and Water Assessment Tool (SWAT). With this analysis we aimed to improve model parameterisation and calibration efficiency. In contrast to less sensitive parameters such as tillage depth and mixing efficiency we parameterised sensitive parameters such as curve number values in detail.In the second step the analysis consisted of varying management practices (conventional tillage, conservation tillage, and no-tillage) for different crops (spring barley, winter barley, and sugar beet) and varying operation dates. Results showed that the model is very sensitive to applied crop rotations and in some cases even to small variations of management practices. But the different settings do not have the same sensitivity. Duration of vegetation period and soil cover over time was most sensitive followed by soil cover characteristics of applied crops. 相似文献
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在作物的生长过程中,水和肥是必不可少的两大要素,合理的灌溉和施肥对作物减投增效十分有利。传统的“大水大肥”方式不仅会降低水肥利用率,而且还加剧了农田土壤环境的污染问题。水肥一体化技术作为一项将水分和养分耦合运筹的新技术,可达到精准施肥、改善土壤环境、节水增产等目的,从而有效缓解资源与环境的矛盾问题,推动绿色农业的可持续发展。本文先综述了辣椒的生长发育、干物质积累、水肥利用、产量及品质指标对水肥一体化的响应,并针对该技术在农业生产中的实践应用,提出合理利用智能系统、多要素一体化技术和耦合模型规划建议,以期为水肥一体化在辣椒高产栽培中的应用提供参考。 相似文献
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Information about soil nutrient carryover dynamics can assist cotton producers with the optimal management of potassium (K) fertilizer. Optimal K management promotes cotton plant health, may decrease input costs, and increases cotton lint yields. A dynamic programming model was developed to determine optimal K application rates and economic returns under different soil information scenarios based on cotton yield response to K fertilizer and fertilizer carryover estimates from a multi-year field trial. A Monte Carlo analysis was conducted to simulate the impact of stochastic input and lint prices and cotton yield on K management over a five-period planning horizon. Results suggest that soil test data could provide important information about K carryover potential, which may lead to more efficient fertilizer use and higher profit margins for cotton producers. 相似文献