In 2016, the Central Deep Reform Group put forward the Reform Plan for Establishing Green and Ecological Oriented Agricultural Subsidy System, thus how to establish green and ecological oriented agricultural subsidies became the focus of hot discussion in academic circles. And this paper attempts to establish a precise agricultural green and ecological subsidy strategy from the perspective of the whole agricultural industry chain.Taking the whole agricultural industry chain as a perspective, this study discussed the agricultural green ecological subsidy links and promotion strategies from the agricultural production link, processing link, distribution link and brand building link. The results found that agricultural green ecological subsidies should be oriented to the sustainable use of resources and environment, and the green and high quality products should be the target, and the subsidy methods and amounts should be "linked" to the greening of agricultural industry. The subsidy mechanism was combined with incentive and control, and the precision and directivity of the subsidy were improved. Based on the above ideas, the strategies of green ecological subsidies in different links are proposed as follows.（1） Subsidies in the production link should be based on chemical input reduction, resource utilization of agricultural waste and green technology adoption producers as the main body, and the corresponding subsidies should be made according to the results of green production assessment;（2） Subsidies in the processing link should be based on the level of processed products and subsidies for resource utilization of waste, etc., so as to improve the precision and direction of subsidies in the processing link.（3） Subsidies in the circulation link should invest for the construction of infrastructure for the circulation, storage of agricultural products.（4） In the brand building process, the subsidy policies should be from the government and the market, and promote the formation of high-quality and low-price markets, so as to achieve high-quality development of agricultural products.
[目的]为充分了解"十一五""十二五""十三五"期间中国肉牛养殖及育肥养殖生产布局的阶段特征、变迁路径和影响机制.[方法]文章运用2008-2019年中国各地肉牛年末存栏量和牛肉产量数据,利用生产集中度、生产重心迁移轨迹阐述生产布局的阶段特征和变迁路径,利用莫兰指数、吉尔里指数和G指数分析空间相关性,利用空间面板模型分析影响因素及效应.[结果]肉牛养殖生产重心向西北方迁移了154.6km,自2017年空间正相关逐渐显著,粗饲料资源禀赋、劳动力质量、技术进步和非农就业机会是布局变迁的重要影响因素;肉牛育肥养殖生产重心向西迁移了119.15km,三大指数均具有显著性,饲料资源禀赋、劳动力质量、技术进步、市场价格、交通通达度、畜牧产业比较优势和非农就业机会是布局变迁的重要影响因素.[结论]肉牛养殖和育肥养殖均呈现出由农区向牧区迁移趋势,且存在空间正相关性,但具体变迁路径和影响机制有所差异,就此提出"合理编制肉牛生产规划、系统加强流通环节建设、强化科学技术支撑、保障饲料稳定供应"的政策建议.
[目的]摸清耕地"非粮化"类型的时序数量转移和空间动态分布特征,为实现耕地"非粮化"分类管控提供科学方法和依据.[方法]文章以西北旱区农业生产典型县陕西大荔为研究区域,基于2000年、2010年和2020年3期的遥感解译数据,运用土地利用转移矩阵和标准差椭圆的方法,探究大荔县耕地"非粮化"的时序数量转移及空间动态分布特征.[结果](1)数量变化上,20年间大荔县耕地"非粮化"类型呈多元化增加趋势,且近10年"非粮化"率急剧上升;(2)转移类型上,20年间粮食作物是耕地"非粮化"面积增加的最大转出者,其中2000-2010年主要转向杂果树类,增量较小;2010-2020年主要转向杂果树类、设施农业和水产养殖,增量巨大;(3)空间动态上,20年间大荔县耕地"非粮化"的空间集聚性特征加强,其中粮食作物和撂荒地向南部地势较低区域集聚;杂果树类、苗圃花卉和设施农业向北部海拔较高区域扩张;而水产养殖向东部河流集聚.[结论]根据西北旱区不同耕地"非粮化"类型的时空演变特征,为政府分类管控"非粮化"现象、优化区域布局和生产结构提供参考依据.
[目的]粮食安全事关经济健康发展、社会和谐稳定,是防范和化解系统性风险,维护国家安全的重要保障.对粮食安全发展水平进行评价研究是准确把握我国粮食安全发展现状、合理制定国家粮食安全相关政策措施的手段.[方法]随着我国进入新发展阶段,国家粮食安全被赋予新的时代内涵和新的发展目标.文章以我国粮食安全在新发展阶段所呈现出来的内涵和目标为导向,从供给能力、供给结构、绿色发展、经济效益以及基础支撑五个方面出发,构建了包括25个具体评价指标的粮食安全评价体系,并建立熵权TOPSIS模型对我国粮食安全发展水平的演变和现状进行评价研究.[结果]进入21世纪,我国粮食安全水平呈现出先下降后上升的发展态势,且对绿色发展、经济效益和基础支撑的重视程度逐年提升;提升我国粮食安全水平受到资源状况、科技水平、供给结构等因素的制约.[结论]保障和提升我国粮食安全水平,需要重点从耕地资源保护和利用、粮食科技支撑、国内外市场与资源整合等方面发力.
Rural residents pay is an effective way to bridge the funding gap for domestic waste management. A systematic study on the willingness to pay and the level of payment and the influencing factors of domestic waste management fees among rural residents is useful to promote the establishment of a payment system for domestic waste management among rural residents. The article is based on the survey data of 2420 rural households covering all prefecture-level cities in Jiangsu， and the empirical analysis is conducted using the Heckman two-stage model. （1） Rural residents mainly dispose of domestic waste without sorting， and about two-thirds of rural residents are willing to pay for the treatment of domestic waste and are willing to pay 49.31 yuan per household per month or 19.84 yuan per person per month. （2） Health status， resident population， net funds at the end of the year， incentives and penalties significantly affect rural residents’ willingness to pay for domestic waste treatment. （3） Age has a significant negative effect on the level of rural residents’ domestic waste treatment fee payment， and net funds at the end of the year， domestic waste treatment methods， the role of village organizations in habitat improvement， trust in relevant laws and regulations， incentives and punishments， personal environmental behavior determination， the impact of domestic waste on the community environment， and regional variables have a significant positive effect on the level of rural residents’ domestic waste treatment fee payment. Payment standards should be reasonably determined， rural domestic waste input mechanisms should be improved， and relevant policies and regulations should be formulated and implemented to guide rural residents to pay domestic waste treatment fees.
[目的]推广绿色农业技术是缓解生态环境恶化、保障农业高质量发展的重要途径.[方法]文章利用河北省436户设施蔬菜种植户的调研数据,选择5项绿色农业技术(抗病虫抗逆性强的新品种、生物防治、生物菌肥、生物农药和水肥一体化技术),基于培训主体异质性视角,运用有序 Probit 模型实证分析公益性和市场性两种不同性质农技培训主体对农户绿色农业技术采纳强度的影响.进一步,基于技术异质性视角,运用二元 Probit 模型分析两种不同性质主体对农户不同类型绿色农业技术采纳的影响.[结果](1)农技培训能够显著促进绿色农业技术采纳,其中公益性主体开展的技术培训对农户绿色技术采纳的促进效果更加显著.(2)针对不同绿色农业技术,不同性质主体开展的培训对技术采纳的促进效果存在差异,对商业化程度较高、有用性、易用性、适用性较高的技术(生物防治、生物菌肥和生物农药),市场性主体的培训对技术采纳的促进作用更强.(3)对于有用性、易用性和适用性不高的技术(抗病虫抗逆性强的新品种和水肥一体化),公益性主体的培训对技术采纳的促进作用更强.[结论]应加大农业绿色技术培训的普及力度,构建以公益性农技推广机构为主导,其他市场主体为补充的多元化农技培训体系,提高农业技术培训的针对性,建立农业技术培训的跟踪服务机制,促进绿色农业技术采纳.
[目的]通过检索分析CNKI数据库,客观把握高标准农田建设研究现状及热点话题,揭示研究路径演变的内在逻辑,探索前沿课题,以期为未来进一步研究提供新视野新思路.[方法]文章运用文献计量方法,利用CiteSpace软件对2000-2022年高标准农田建设相关文献关键词进行检索,绘制发文量、关键词共现、聚类、突现、时间线图谱并进行可视化计量分析.[结果](1)近年来高标准农田建设领域内研究成果持续增长,研究内容呈现多元化发展.(2)在发文作者方面,该研究领域作者呈现出"集中度高、联系广泛"的特点.作者间的合作集中且普遍,以高产作者为中心,逐步形成了一些核心研究团队.但同时也存在相当比例的独立研究者.发文机构方面则展现出以核心研究机构为主导,带动其他机构协同研究的特点.各研究机构间的沟通交流密切且频繁.(3)关键词共现和聚类图谱显示土地利用、粮食安全、土地整治、耕地质量等主题热度最高.时间线图谱表明产能提升、科技创新、生态环境、监督管理等是未来新的研究方向.[结论]应深化高标准农田建设对粮食综合生产能力影响机制相关理论研究,加强高标准农田建设制度保障设计和重点环节实际建设相关研究,完善微观层面高标准农田建设效果评价研究.进一步挖掘政策潜力,构建与"藏粮于地、藏粮于技"战略、乡村振兴战略、农业农村现代化建设协同发展框架,以期最大程度发挥高标准农田建设成效.
Food security is one of the major challenges facing by human society, and it is also an important agenda of the United Nations Sustainable Development Goals. Ensuring food security is related to the national economy,people’s livelihood, and social stability. Reasonable regulation of planting structure, optimization of grain ratio and output play a decisive role in stabilizing food security. Farmers’ planting decision behavior is the main factor affecting the planting structure of staple grains. At present, the self-sufficiency rate of oil crops is low, especially the self-sufficiency of soybean. To optimize the planting structure, it is necessary to quantitatively evaluate the farmers’ planting decision behavior and its impact. This paper took the major food production region Songnen Plain in Heilongjiang province as the research area. By integrating farmer household survey data, socio-economic statistics, and land use data, we used an agent-based model to simulate farmers’ planting decision behavior and the spatial distribution pattern of crops from 2016 to 2020, with the simulation average overall accuracy of 63%. The results showed that planting decision behavior was strongly related to social norms. For example, if most of the farmers in the society of planting rice, the farmer would also choose to plant rice. Another significant factor was economic factors, such as planting net income. According to the prediction of the ABM model, the higher the degree of influence of farmers on the planting decisions of surrounding farmers, the more inclined they were to choose the planting structure of the surrounding farmers; and when the amount of soybean subsidy changed, farmers were more inclined to choose the planting structure with higher planting income. Therefore, the analysis provides method reference for the simulation of farmers’ planting decision behavior in other regions, so as to put forward targeted policy suggestions, and ensure food security and social stability.
Agricultural resources and environment are the basis for quality assurance of agricultural products.Agro-scientific and technology innovation empowers the development of agricultural industry. Exploring the influence factors and economic benefits of agricultural green production technology is of great significance to ensure the green development of agricultural industry and improving famers’ adoption of green production. Based on the data of 219 farmer households obtained from the field survey in Dingxing county, Hebei province in 2020, we analyzed the factors affecting farmers’ adoption of green production technology through a binary Logistic model.Then we studied the effect level of technology adoption on the economic benefits of farmers’ households by using a propensity score matching method. The results were listed as follows.（1） Our analyses indicated that although the promotion of green production technology in Dingxing county had led to a total of 67.58% of farmers adopting at least one or more green production technologies, the degree of adoption needed to be improved.（2） Farmers’ age,education level, type of greenhouse, joining cooperatives, technical training, and government’s guidance significantly affected farmers’ decision on technology adoption.（3） Compared with the non-adoption group, the average income of farmers who adopted green production technology had increased 28.44% per hm2; soil testing formula technology and green pest control technology brought 26.52% and 14.90% of the income increase effect respectively. Water-saving irrigation technology and waste recycling technology had no significant effect on increasing income. Therefore, because the green production technology has significantly increased the income of farmers, the government should strengthen the promotion of green production technology, and improve farmer’s adoption of green production technology through technical training, economic incentives, and the establishment of a technology promotion system.
Crop remote sensing classification is a key issue in crop area monitoring, which is of great significance for further monitoring crop growth and yield. Feature selection is an important step in crop remote sensing classification, which can effectively improve the accuracy and efficiency of crop remote sensing classification. In this paper, backward elimination feature selection method was used to determine the size and content of the optimal feature subset, and the classification accuracies of different optimal feature subsets was compared to analyze the strengths and weaknesses of four feature ranking methods. Firstly, 3 types of features, 114 in total, were extracted from RADARSAT-2 data during the key growth period（June 3rd, June 27th, July 21st） of dryland crops in Shenzhou city, Hebei province. Then, the importance of the features was ranked based on four measures. And the backward elimination method was used to simplify the feature variables, determine the optimal number of features,and obtain the optimal feature subsets. Finally, the classification results of different optimal feature subsets under random forest were compared. The results showed that Extremely Randomized Trees was the best method in feature selection. When the feature subset selected by Extremely Randomized Trees algorithm participates in the random forest classification, the highest accuracy（92.63%） could be achieved with only 11 features. In addition, compared with the classification results of all 114 features, the overall accuracy was only reduced by 1.78%. In summary, this study demonstrated the optimal feature subsets selected by backward elimination feature selection can confirm the number of the optimal features. When used for dryland crop classification, the optimal feature subsets can effectively improve the classification efficiency on the premise of ensuring the classification accuracy. The optimized feature subset can provide reference for dryland crop classification under the same planting structure.
Ecological development is one of the main trends of agricultural development in China, including tea industry in the future. At present, China is vigorously promoting the construction of ecological tea garden. However,research on evaluation of ecological development level of tea garden is not much, which cannot meet the practical needs of evaluation towards transformation of ecological value in tea industry. Therefore, it is of great theoretical and practical significance to construct a comprehensive evaluation system for ecological development level of tea gardens. This paper established an evaluation index system of tea garden ecological development level from five dimensions, namely ecological environment level, technology and management level, economic benefit, ecological benefit, and social benefit, respectively. The index weight was calculated by the methods of expert consultation and Analytic Hierarchy Process（AHP）. We carried out an empirical research on 17 sample tea gardens, calculated the comprehensive index of tea garden ecological development level and adopted the obstacle degree model to identify the factors hindering the improvement of the ecological level. The results were showed as follows. The evaluation results of 17 sample tea gardens we basically consistent with the original judgment. The main obstacles to ecological development of the sampled tea gardens were soil and water conservation, and the diversity of soil microorganisms（bacteria and fungi） in the dimension of ecological benefits, and whether there was zero detection of pesticide residues in the dimension of tea product safety and quality. Therefore, the evaluation system of tea garden ecological development level constructed in this paper shows strong operability and good practical value, and can be applied to evaluate the ecological level of tea garden.
Fertilization is an effective management practice to maintain the nutrient balance of grassland ecosystems. A field study was used to study the effects of different organic fertilizer application rates on plant communities, aiming to provide reference and to reveal mechanisms for the restoration and improvement of degraded grasslands. And the study was conducted on the Leymus chinensis meadow steppe for fertilization control experiment in Hulunbuir, Inner Mongolian from 2014 to 2021. There were four fertilizer application rates for the experiment: no fertilizer application, the low level of application, the medium level of application and the high level of application correlations and interactions among plant species importance values, functional groups and community species diversity under different fertilizer application rates were analyzed. The results were listed as follows. The important value of Leymus chinensis showed a trend of the parabolic function with fertilizer application rates, reaching its highest value at the medium level; the plant characteristic values of community and Leymus chinensis after organic fertilizer addition were significantly higher than those of the non-fertilized treatment; the plant community species diversity index decreased with fertilizer application rates. The response ratios of community height, density, coverage and above-ground biomass with fertilizer amendment were significantly higher than those without fertilizer application; the tendency for the plant community species diversity index response ratio to decrease with increasing levels of fertilizer application was relatively significant. The interactions between community functional groups and fertilizer rates were significant, and the important values of Gramineae, Leguminosae and Ranunculaceae were significantly different between without and with fertilizer applications; there was a highly significant negative correlation between the important values of Gramineae and the diversity index, a highly significant positive correlation between the important values of Leguminosae, Gentianaceae, Ranunculaceae, Umbelliferae, and Cyperaceae and the diversity index, and a significantly positive correlation between the important values of Liliaceae and Iridaceae and the Pielou evenness index. In summary, there is a significant interaction and correlation between the major functional groups of Gramineae, Leguminosae and Ranunculaceae in the community and fertilizer amendment. Organic fertilizer applications resulted in reducing the species diversity index and its response ratio of the Leymus chinensis meadow steppe plant community, and increasing the important values of Gramineae and Leymus chinensis and grassland productivity.
Sorghum is an important multi-purpose economic crop in dryland in China. In the context of its wide production area, complex ecological conditions, and diverse cultivation methods, it is very imperative to establish an evaluation index system for ecological adaptability of sorghum variety, which is of significance for guiding variety selection and planting planning. Through literature research, production research and expert questionnaire, the hierarchical structure of the index system of variety ecological adaptability evaluation was constructed by using analytic hierarchy process, and the Delphi method and orange office software were used to design the questionnaire,the expert WeChat group was used to investigate the relative importance of each index, then the SPSSAU priority chart method was used to calculate the weight of each index. According to repeated consultation, the scoring principles and standards of various indicators were determined, and based on the comprehensive score, the ecological adaptability of sorghum varieties was divided into three categories: adaptation（≥ 90 points）, relatively adaptation（76～89 points） and non-adaptation（≤ 75 points）. According to the established evaluation method, six representative varieties was comprehensively scored and evaluated in 6 regions. It concludes that the results are proved to be in line with the reality.
Agricultural branding has become a core symbol of agricultural modernization. Digital identification provides digital information and technical support in promoting brand building of agricultural products. However,there is still a lack of systematic and scientific research on the collaboration between them. Using literature review,comparative analysis, case analysis and other methods, the present study clarified the concepts of the two areas of digital identification and brand strategy of green agricultural products, analyzed the achievements and issues in the above two areas in China, and proposed approaches to promoting collaboration between these two areas in China.The present study clarified the essence and extension for the areas of digital identification and brand strategy of green agricultural products, as well as the relationship between the two areas. Based on the synergetic theory, the conceptualization and mechanisms were presented for the collaboration between the two areas. It pointed out that the digital identification of green agricultural products promoted agricultural brand strategy and brand value, and the agricultural brand strategy promoted the innovation and upgrading of the digital identification of green agricultural products. China had made remarkable achievements in the collaboration between digital identification and brand strategy of green agricultural products. However, there were some problems, such as the incomplete agricultural standards system, rudimentary infrastructure, lack of standardized systems for both agricultural product quality certification and certification management, etc. Therefore, the collaboration between digitalizing green agricultural products and brand strategy can be promoted by the enhancement in the following aspects:establishment of a lively agricultural branding ecosystem, development of standardized platforms for traceability systems and pertinent technology, innovation as well as independent R ＆ D and implementation, brand promotion and marketing, pilot work, etc.
Public participation is the key to building a grassroots governance community. An in-depth analysis of the factors influencing farmers’ willingness to participate in democratic decision-making is important for improving rural self-governance and achieving effective governance. Based on the data from the China Comprehensive Social Situation Survey in 2019（CSS2019）, this paper analyzed the influence of social capital on farmers’ willingness to participate in democratic decision-making and its mechanism by using logistic regression, mediating effect and moderating effect tests. The results showed that（1） Social capital had a significant positive influence on farmers’ willingness to participate in democratic decision-making and promoted farmers’ democratic participation effectively.（2） Political efficacy was the intermediary variable of social capital’s influence on farmers’ willingness to participate in democratic decision-making, with its indirect influence accounting for 78.1%.（3） Income level moderate the influence of political efficacy on farmers’ willingness to participate in democratic decision-making.The higher the farmers’ income level, the stronger the contribution of political efficacy to farmers’ willingness to participate in democratic decision-making. Therefore, social capital, political efficacy and income level are important factors influencing farmers’ willingness to participate in democratic decision-making. More attention should be paid to the cultivation and enhancement of farmers’ social capital, and efforts should be made to improve farmers’ political efficacy and income level.
[目的]提升植被碳汇被视为应对气候变化、如期实现"双碳"目标的重要抓手.尽可能全面地识别农地细碎化对植被碳汇的影响,能够从侧面展示农地细碎化治理蕴藏的生态价值.[方法]文章基于卫星遥感数据,测算2001-2019年中国省级农地细碎化和植被碳汇水平,采用双向固定效应模型和空间计量模型实证考察农地细碎化对植被碳汇的影响.[结果](1)农地细碎化会显著降低植被碳汇,农地细碎化指数每增加1%,植被碳汇降低0.127 4%.(2)从农地细碎化维度来看,面积和分布细碎化均会显著降低植被碳汇.(3)从土地覆被类型来看,农地细碎化的影响并非局限于农地,同样会降低林地和草地碳汇,农地细碎化指数每增加1%,林草碳汇降低0.138 5%.(4)从空间关联来看,农地细碎化的影响并非局限于当地,同样会降低周边地区植被碳汇,存在空间溢出效应.(5)农业综合开发的土地治理项目能够降低农地细碎化对植被碳汇的负面影响,且相较于自筹资金,财政资金的治理效应更优,相较于农地治理,生态综合治理的治理效应更优.[结论]应加强"生命共同体"系统思维,全面认知农地细碎化影响植被碳汇的广度和深度,重视农地细碎化治理的生态价值.在农地细碎化治理中充分发挥政府的主导作用,将生态保护和修复列为农地细碎化治理的前提.
[目的]探索数字乡村发展对农业绿色全要素生产率的影响及作用机制,为实现农业高质量发展提供新的经验依据.[方法]文章基于2014-2020年中国31个省(市、自治区,不含港澳台)面板数据,分别利用信息熵指数法和数据包络分析法对数字乡村发展水平和农业绿色全要素生产率进行测度,运用修正的引力模型和社会网络分析法识别数字乡村发展水平的网络关联特征,在此基础上通过所识别的非对称空间网络权重,构建时空双固定的空间杜宾模型探讨数字乡村发展对农业绿色全要素生产率的网络溢出效应.[结果](1)数字乡村发展水平较高的省份主要分布在长三角、京津冀及珠三角地区,分省数字乡村发展水平在样本期内均呈不同程度的上升趋势,但省份间差异明显.(2)省际之间数字乡村发展水平的联系,已超越地缘意义上的相近,呈现为复杂、多线程的空间网络结构,网络溢出效应较为明显.(3)基于空间关联网络,数字乡村存在显著的空间自相关性,能显著提高当地农业绿色全要素生产率,但对相关联省份具有负向溢出效应.[结论]各地应将数字乡村作为推动农业高质量发展的重要抓手,适度有序推进自身的数字乡村发展进程;与此同时,重视数字乡村的协调发展,减少因区域发展不平衡而产生的空间负外部性,根据各省域数字乡村发展的空间关联规律,制定差异化的数字乡村发展政策.
[目的]促进共同富裕的重点和难点仍然在农村,文章旨在探讨农村劳动力流动对农户共同富裕的影响机制与效应.[方法]基于2018年中国家庭追踪调查(CFPS)数据,首先从经济水平、精神富裕和生活质量等5个维度对农户共同富裕水平进行了测度,然后检验了农村劳动力流动对农户共同富裕的影响效应,并进一步讨论了劳动力流动范围和就业稳定性对农户共同富裕的影响.[结果](1)农村劳动力的流动显著促进了农户共同富裕,在通过采用有序响应模型Ologit和倾向值匹配(PSM)方法检验后,研究结论依然稳健.(2)从农村劳动力流动的范围来看,县域内的流动对农户共同富裕的促进效应最大,而跨省流动的促进效应最小.(3)从农村劳动力就业的稳定性来看,稳定就业对农户共同富裕的促进效应大于非稳定就业.[结论]要加快推进县域城镇化发展,完善农民工市民化的政策,提升农村劳动力就业的稳定性,确保其在教育、医疗和社保等方面的同等待遇,真正实现农村转移人口的城市社会融合,从而促进共同富裕.
[目的]在奶业振兴背景下,分析当前我国乳制品供给能力提升与奶源自给率下降等问题,是完善乳制品供给安全的重要保障.[方法]文章基于美国农业部、联合国粮农组织、国家统计局、海关总署与《奶业年鉴》等数据,通过分析国内外乳制品生产、消费和贸易格局变化,梳理并分析全球乳制品供需背景下中国乳制品供给安全所面临的挑战.[结果](1)全球原料奶产量增长乏力,国际乳制品供给增长空间有限.(2)我国奶源自给率明显下降,供需缺口进一步扩大.(3)国内乳制品生产与消费结构相对单一,乳制品行业仍具备较大提升空间.(4)乳制品进口贸易对外依赖度加大,进口集中度高,风险分散能力弱.[结论]应确立保障我国乳制品供给安全战略导向,优化产需结构;统筹内外发展,平衡乳制品供给对外依存度;完善市场稳定机制,强化风险防控能力;促进奶业技术进步和绿色发展,缓解资源环境约束问题.
