Quantitative Simulation of Dynamic Changes in Cultivated Land in Areas of Reclamation and Returning Cultivated Land to Forest or Pastures under RCPs Climate Scenarios

Northeast China as one of important agricultural production bases is an area under reclamation and returning cultivated land to forests or pastures. Therefore, it is of great practical significance in guaranteeing the sustainable development and national food security to study the spatial and temporal variation of cultivated land in Northeast China under future climate scenarios. In this study, based on data of land use, natural environment and social-economy, dynamics of land system（DLS） model was used to to simulate the spatial distribution and changing trends of cultivated land in the typical areas of reclamation and returning cultivated land to forest or pastures in Northeast China during 2010-2030 under land use planning scenario and representative concentration pathways（RCPs） scenarios quantitatively.The results showed that the area of cultivated land had an overall decreasing trend under the land use planning scenario, but the area of upland field increased slightly from 2000 to 2010 and then declined greatly, while the area of paddy field continuously declined from 2000 to 2030. Under the Asia-Pacific Integrated model（AIM）scenario, the total area of cultivated land had a tendency to increase considerably,with the upland field expanding more obviously and the paddy field declining slightly.In addition, the cultivated land showed a greater decreasing trend under the model for energy supply strategy alternatives and their general environmental impact（MESSAGE） scenario compared to the land use planning scenario. Moreover, analysis on the conversion between different land use types indicated that the reclamation and returning cultivated land to forests or pastures was likely to continue under future scenarios, but the frequency of occurrence could decrease as the time goes by. The conclusions can provide significant decision-making information for the rational agricultural planning and cultivated land protection in Northeast China to adapt to the climate change.

Evaluation of the Land Production Potential in the Context of Returning Farmland to Forest in Karst Region:A Case Study of Guizhou Province

In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.

The Space Dissimilation of Stakeholders' Environment Cognitive and Behavior Preference Response in the Area from Returning Fazing Land to Grasslands

The cognition and attitudes of resources environment affect environmental behavior of behavior subject,the changes of attitude and behavior become one of the key factors of influencing harmonious and healthy development of ecological environment. With PRA survey method for obtaining questionnaire data and based on behavior geography and social psychology theory,farming-pastoral,dry grassland,desert grassland, typical project village alpine grassland of returning fazing land to grasslands as an example,with main body cognitive perspective of the aid of resources,the article analyzed space dissimilation of stakeholders environmental cognitive and behavior preference response in the area of returning grazing land to grasslands from ecological environment from policy environment,ecological environment and family economic environment aspects. The results showed that： stakeholders judgment of Grassland degradation in different ecological function area had obvious regularity,the cognitive proportion of Grassland degradation gradually increase from farming-pastora to alpine savanes. The satisfaction from returning grazing land to grasslands showed a changing tendency of reversed U. stakeholders had more strongly negative cognition in the area of dry steppe and desertsteppe. From farming-pastoral to alpine savanes,the economic environment tend to worse situation. Negative environmental behaviors tend to increase,Positive behavior on the contrary.

退耕还林地生态环境损害评估案例分析及应用

近年来,随着我国经济的高速发展,林地生态环境损害事件日益增加。不同类型的生态系统或同一生态系统在不同区域所提供的生态服务功能侧重均不同,鉴定评估林地生态系统的环境损害价值时应选用不同的测算方法。通过阐述理论公式法和实际监测法的原理和适用范围及其在生态环境损害评估中的应用,并对量化过程中参数的选取原则与方法进行说明。结合案例分析非法占用退耕还林地导致的生态环境损害范围和程度,计算出2012年~2019年的生态环境损害价值量为205万元。研究退耕还林地生态环境损害典型案例,并将其推广应用于小规模普通林地,对林地生态环境损害案件的鉴定评估环节具有重要引领作用。

乡村集体土地制度对返贫风险治理的影响及优化路径

乡村集体土地制度是一个承载着历史印记的制度安排,其变迁对中国农村经济社会发展产生了深远的影响。在乡村振兴战略背景下,乡村集体土地制度对治理返贫风险尤为关键。当前,乡村集体土地使用存在权属不清、流转不畅、利用效率低下等问题,制约了乡村经济的进一步发展。文章基于这些问题分析了乡村集体土地制度对返贫风险治理的多维效应,包括收入效应、就业效应、社会效应和环境效应,并针对乡村集体土地使用的问题和改革的局限性,从完善集体土地所有权制度、使用权制度、经营权制度,创新土地利用方式,强化土地空间规划布局等方面提出了一系列治理路径设计,以提高土地使用效率,保障农民权益,有效降低返贫风险,激活乡村内生动力,增强乡村发展韧性。

发包方终止土地经营权流转合同探究

《农村土地承包法》第64条赋予了发包方终止土地经营权流转合同的权利,目的在于切实保护集体土地所有权,避免集体土地遭受损害。发包方终止土地经营权流转合同的权利属于形成权,但不是合同解除权,不仅适用于土地经营权流转合同,也适用于土地经营权再流转合同以及融资担保实现后流转的土地经营权,不适用于其他方式承包的承包合同。在土地经营权人擅自改变土地的农业用途、弃耕抛荒连续两年以上、给土地造成严重损害或者严重破坏土地生态环境的情形下,若承包方不行使合同解除权,则发包方有权终止土地经营权流转合同。发包方行使终止土地经营权流转合同的权利可以采取通知终止与诉讼终止两种方式行使。在合同终止后,土地经营权人应当向承包方返还承包地,地上物应当按照充分发挥物的效用原则处理,承包地的权利负担随之消灭,同时应当办理注销登记。

黄土高原退牧还草工程实施成效认知评价——以甘肃省环县为例

【目的】全面评估退牧还草工程实施以来黄土高原区域所取成效与面临问题,优化后续工程的实施。【方法】以黄土高原区的甘肃省环县为例,开展退牧还草工程实施成效认知评价。通过实地考察、入户调查和访问座谈,结合管理部门、实施对象的意见和建议,从退牧还草工程特点出发,构建基于层次分析(AHP)-模糊综合评价法的评估模型,对实施成效认知进行了评估。【结果】黄土高原区退牧还草项目农牧民认可度高,实施成效综合得分75.94,处于中等偏上水平,在生态修复方面取得了较好成就,对当地经济建设起到了促进作用。【结论】建议后期工程实施中加大对实施必要性的宣传,让生态保护观念更深入人心,结合社会变迁的情况,辅以科技支撑、产业结构调整、政策导向等方式,促进新时期黄土高原类似地区的生态建设与高质量发展。

玛曲县退牧还草工程实施效果评估

为了综合评价甘肃省玛曲县在第二轮退牧还草工程(2005~2020年)实施中取得的成效,本文构建经济效益、生态效益、社会效益、工程的可持续性、工程的自身特性5个准则层、17个指标层的综合评价体系。采取随机抽样的方法展开问卷调查,结合相关部门意见构建层次分析-模糊综合评价模型,对实施成效进行评估。评估结果表明,自退牧还草工程实施以来,当地生态效益(0.4274)上升最为显著,其次是经济效益(0.2658)、社会效益(0.1693)、工程的可持续性(0.0838)和工程的自身特性(0.0564)。虽然退牧还草工程取得了显著的生态成效,但如何使成果持续有效地延续下去至关重要。通过项目实施前后指标层的权重分析,建议政府需加大与科研院所的合作力度,采取近自然修复技术,选择适合高寒环境的乡土草种补播,提高草场的生物多样性和稳定性;引领牧民构建畜产品产业链,促进第二、三产业发展,向以非传统牧业为主的经济收入模式迈进;加大对牧民文化教育事业的投入,提高牧民保护草原的生态意识;构建以草定畜、草畜同步发展的自然-人文耦合系统下的放牧模式和“减畜不减产、减畜不减收”的草地农业模式,促进草场可持续发展。以上研究结果有助于政府对退牧还草工程制定科学的规划和宏观的管理措施。

Changes of Organic Carbon in Soil under Different Land Use Patterns in Alpine Agricultural Region of Qinghai

Using organic carbon density grouping method,the change trends of soil total organic carbon(SOC),light fraction content and light fraction organic carbon under 4 land use patterns of returning cultivated land to forest(cropland,artificial forest,inter-cropping of forest and grassland and original sample plot)in alpine agricultural region of Qinghai were studied.The content of SOC was in order:intercropping of forest and grassland > original sample plot > artificial forest > cropland.There was signi...

玉米秸秆还田对土壤地力及固碳能力的影响

为探明农产品化肥减量后土壤养分的变化,促进玉米秸秆还田,提升土壤肥力,从2019年开始在黑龙江省大庆市所属4个牧场连续3年进行玉米秸秆还田试验,期间随机选取31处采样点分别进行3次抽样,分析土壤样品中pH、碱解氮、有效磷、速效钾、有机质、有机碳和水溶性盐等指标,以此判断玉米秸秆还田对土壤地力和固碳能力的影响。结果表明,长期玉米秸秆还田土壤中有机质含量由21.2 g·kg^(-1)增长至23.6 g·kg^(-1);秸秆还田土壤中有效磷的含量平均增长约144.0%,而未还田土壤中有效磷含量的平均增长约138%;碱解氮含量由166.50 mg·kg^(-1)增长至194.50 mg·kg^(-1),且2022年与2021年测定的碱解氮含量差异显著。可见秸秆还田后土壤固碳能力增加,肥力增强,而pH一直维持在7.92~8.23。因此,合理运用玉米秸秆还田可改善土壤耕作环境,减少土壤中盐分聚集,提高土壤对有机碳的固定效果,调节土壤的酸碱稳定性,对东北土壤生产力的可持续发展具有重要意义。

基于无人机机载激光雷达的退圩还湖实施效果监测

为弥补传统人工复核退圩还湖进度时空分辨率低、耗时长的缺点,利用无人机搭载高精度激光雷达对平旺湖退圩还湖实施效果进行监测。基于获取的激光点云数据,采用工作流的技术方法,建立平旺湖DEM和DSM及坡度精细化模型,实现退圩还湖区域内排泥场和成湖区空间信息的特征提取。采用同期GPS现场测量成果和高分遥感影像分别对高程、面积进行精度验证,结果显示:激光雷达高程总体中误差为0.023m,其中岸线高程提取精度略低于水面,提取的面积与高分影像人工目视解译结果对比精度达99.3%,且更加接近退圩还湖实施方案的要求,表明无人机机载激光雷达技术可有效运用于退圩还湖工程的动态监测,为掌握工程实施效果、科学调整工程进度提供技术支撑。

退牧还草政策下退牧户违规放牧与地方政府监管的演化博弈分析

退牧户违规放牧行为不利于退牧还草政策的可持续实施。违规放牧行为与地方政府监管之间的动态博弈分析能定量化理解二者行为的成本效益边界,有助于制定合理有效的监管对策。从微观主体的收益函数出发,构建地方政府监管与退牧户违规放牧的演化博弈模型,根据复制动态方程分析参与方的行为演化规律及稳定策略,利用Python仿真工具探讨草地有效治理的影响因素。研究发现:(1)在特定条件下,可实现地方政府监管、退牧户不违规放牧的动态均衡;(2)提高违规放牧罚款、增加工程补贴、加大政府监管压力、提高退牧户其他收入,均能有效减少违规放牧;(3)监管成本增加会延缓均衡达成;(4)违规放牧收益增加会延长退牧户达到均衡的时间,但缩短政府达到均衡的时间。基于此,本研究提出加大处罚力度、优化补贴政策、完善监督机制、提供就业培训等建议,为制定遏制违规放牧的政策提供科学依据,促进生态保护与民生福祉协调发展。

共同富裕愿景下农村土地捐赠问题研究

遵循第三次分配和共同富裕的理念与精神,创新地提出农村土地捐赠的概念。基于科学合理的激励机制,促使部分先富裕起来的农户将土地捐赠给本集体经济组织内低收入的无地少地农户,以达到先富带后富、促进共同富裕的目标。从此视角出发,构建起农村土地捐赠的运行机制,在农村土地捐赠执行过程中可能面临着三个方面的问题:土地捐赠的参与主体不积极和捐赠数量不充分、土地捐赠的管理主体和监督主体不明确、捐赠土地的再利用方式不清晰。这些问题的形成原因主要包括:农村土地捐赠的法律政策不健全不完善、农村土地捐赠实施机构的选择面临着自治和法治的困局、农村土地捐赠激励机制的严重缺位、农村土地捐赠的社会氛围尚未形成。据此,提出四条对策建议以助力农村土地捐赠的实现:建立并完善农村土地捐赠的法律政策体系、组建高效联动的农村土地捐赠执行机构、构建多层次的农村土地捐赠激励机制、倡导先富带后富的农村土地捐赠社会氛围。

秸秆生物炭还田对盐碱地土壤特性影响的研究

[目的]盐碱地作为重要的新增耕地后备资源,对于维持耕地数量稳定、保障粮食安全起到至关重要的作用。传统的秸秆处理方式会带来空气污染、土壤退化等一系列的负面影响,因此提高秸秆的综合利用率、推动秸秆资源的环保高效利用对于我国农业的可持续发展和环境保护都具有重要意义。[方法]系统阐述了盐碱地改良措施现状及存在问题,包括物理法、化学法、生物法、水利法等盐碱地土地整治改良的方法,研究了秸秆利用现状及潜力,并综合分析了秸秆生物炭还田对盐碱地土壤物理性质、化学性质、养分及酶活性等的影响。[结果]秸秆生物炭还田在盐碱地治理过程中可以有效抑制土壤表层盐分的积累,优化盐碱地的土壤结构,解决土壤盐碱化问题,同时能够改善土壤理化性质,提升土壤肥力。[结论]秸秆生物炭还田是促进农业可持续发展的重要途径,在盐碱地治理中具有广阔的应用前景,未来可以不断优化改进秸秆生物炭还田的技术和方法,提高其改良效果和经济效益。

秸秆还田和有机肥对宁夏银北盐碱地改良效果研究

研究旨在评估农艺改良措施对宁夏银北灌区盐渍化土壤速效养分、土壤酶活性、土壤物理结构的影响。通过施用有机肥、秸秆还田2种改良措施,并与单施化肥的处理进行对比。结果表明,采取的有机肥(OM)和秸秆还田(RS)2种措施,土壤碱解氮、有效磷和速效钾含量得到有效提高,土壤脲酶和碱性磷酸酶活性显著增强。OM处理>5 mm粒径机械稳定性团聚体占比提高了22.3%,0.5~0.25 mm粒径机械稳定性团聚体占比降低了3.8%;RS处理>5 mm粒径机械稳定性团聚体占比提高了19.1%,0.5~0.25、<0.25 mm粒径机械稳定性团聚体占比分别降低了3.1%、3.2%;OM和RS处理>5 mm粒径水稳性团聚体占比分别提高了29.0%和43.3%,0.5~0.25 mm粒径水稳性团聚体占比分别降低了23.1%和30.1%;OM和RS处理平均重量直径(MWD)分别提高了105.9%和139.7%,团聚体水稳系数(K)分别提高了136.4%和150.5%,团聚体破坏率(PAD)分别降低了28.2%和31.1%,土壤物理结构得到有效改善。这些结果表明,有机肥和秸秆还田是改善宁夏银北灌区盐渍化土壤质量的有效措施。

土地一级开发项目财务评价指标研究

财务评价作为项目可行性研究的一个重要组成部分,是项目立项和决策的重要参考依据。与传统建设项目相比,土地一级开发项目有其自身特点,本文在总结土地一级开发项目财务评价特点的基础上,通过对影响财务评价指标敏感因子的分析,运用蒙特卡洛模拟找出关键敏感因子,并结合实际案例分析关键敏感因子对土地一级开发项目财务评价指标的影响,最终提出在基本财务评价指标的基础上,土地一级开发项目财务评价还应关注的指标。

Effects of Grazing Exclusion on Soil Carbon and Nitrogen Storage in Semi-arid Grassland in Inner Mongolia, China

The semi-arid grasslands in Inner Mongolia, China have been degraded by long-term grazing. A series of ecological restoration strategies have been implemented to improve grassland service. However, little is known about the effect of these ecological restoration practices on soil carbon and nitrogen storage. In this study, characteristics of vegetation and soil properties under continued grazing and exclusion of livestock for six years due to a nationwide conservation program—′Returning Grazing Lands to Grasslands(RGLG)′ were examined in semi-arid Hulun Buir grassland in Inner Mongolia, China. The results show that removal of grazing for six years resulted in a significant recovery in vegetation with higher above and below-ground biomass, but a lower soil bulk density and pH value. After six years of grazing exclusion, soil organic C and total N storage increased by 13.9% and 17.1%, respectively, which could be partly explained by decreased loss and increased input of C and N to soil. The effects of grazing exclusion on soil C and N concentration and storage primarily occurred in the upper soil depths. The results indicate that removal of grazing pressure within the RGLG program was an effective restoration approach to control grassland degradation in this region. However, more comprehensive studies are needed to evaluate the effectiveness of the RGLG program and to improve the management strategies for grassland restoration in this area.

Monitoring the Cultivated Slope Land in the Three Gorges Reservoir Area Based on Remote Sensing and GIS

By means of combining auto-extraction with manual interpretation, the current distribution information about cultivated land is obtained. The distribution information of 1992 is extracted from the dynamic polygons of 2002. The monitoring mini-system of the cultivated slope land is established. In the system, detailed surveys, focused on the resources of cultivated slope land, are carried out. The results indicate that the area of the cultivated slope land is very large. Meanwhile, there are lots of cultivated steep slopes with gradient above 35°. The areas of steep land cultivated had been slowly reduced from 1992 to 2002. At the same time, the pressures of returning farm land to forestry are great in all counties. The conflicts between population growth, insufficient grain supply and stagnant economic development sharpen increasingly. It is inevitable to improve the agricultural structure.

农村建设用地入市的农户期望收益阈值测算及其影响因素

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星历模型下地月自由返回全飞行过程轨道设计

面向载人登月任务需要,针对星历模型下具备自由返回能力的地月转移轨道设计问题进行了研究。在三体模型下对地月三维自由返回轨道进行了求解,得到了地月空间内的自由返回轨道分布情况。在二体模型假设下对近月段的三脉冲变轨进行了求解,给出了变平面机动的计算方法。进一步提出了两轮逐次优化修正策略,分别以高度和再入走廊为主要约束,采用内点法和SQP算法在高精度星历模型下对自由返回轨道初值进行逐次优化修正。之后,采用SQP算法在星历模型下对近月三脉冲变轨进行优化修正,得到了星历模型下的自由返回+近月三脉冲变轨地月转移策略。仿真校验结果表明本文提出的方法能够在给定约束下有效求解星历模型下具备自由返回能力的地月转移轨道,为载人登月任务的转移轨道设计提供参考。