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.

Multi-scales Analysis of Driving Forces on Land Use/Cover Change in China:Taking Farmland Returning to Forest or Grassland as a Case

Increasing populations are causing an increase in food demands, and the area of cultivated land expands every year. Inappropriate land transition from ecology to production results in the constant decline of the ecological security level and influences the regional sustainable development. Adjusting unreasonable land use mode and reconstructing natural land cover are important ways to maintain and improve the ecological environment. Also reclaiming farmland as areas for forests and grasslands (FRFG) is another way. Successful implementation of FRFG in China is the result of comprehensive effect of the multi-scales driving forces. This paper analyses the driving forces of FRFG in China on a national (country) –regional (province) – local (county) – household (farmer) level scale, and the results are: driving forces at the national scale include ecological and food security and the western development of China; at the regional scale, ecological and economic benefits become the main factors to influence the dimension of FRFG under the same policy. The driving forces can be divided into 6 types: industrial structure adjustment, water source protection, flood prevention, the Three-Gorge Project protection, reduction of the amount of sediment flowing into the Yellow River and wind erosion desertification prevention. The driving forces at the local scale can be divided into 12 types with developing leading industries, increasing farmers’ income and improving agricultural production conditions as the main types; at the household scale, the nationalpolicy meeting farmers’ demands and the optimization of individual interests are all driving forces.

Returning Farmland to Forest, Forest Management and Permanent Forest : Thinking on High-quality Development of Returning Farmland to Forest

In the first round of returning farmland to forest,many places in Hubei Province have vigorously developed ecological forests dominated by pine,fir and cypress,to improve the fragile ecological situation as soon as possible.At present,this kind of ecological forests are facing the dilemma of more pure forests,higher density and less management,with worse economic benefits.To realize high-quality development of these stands,it is necessary to carry out forest management guided by the close-to-nature concept.These stands will be transformed into permanent forests with multi tree species,multi age classes,multi levels and continuous coverage,to realize organic unity of economic,ecological and social benefits.

Monitoring and Evaluation of Benefits of Project of Returning Farmland to Forests in Henan Province

The project of returning farmland to forest has been implemented and consolidated in Henan Province for 20 years.At present,it is in a critical transition period when the previous round of project of returning farmland to forests has completed and a new round of project of returning farmland to forests has started.Henan Province took counties(cities)with different representations as sample counties for monitoring the benefits of project of returning farmland to forests(key monitoring areas in Henan Province),and monitored social and ecological benefits every year,and has obtained real and scientific monitoring data.

Effects of Different Modes of Returning Farmland to Forest on Physicochemical Properties of Soil in Bashang Area of Northern Hebei Province

[Objective]The research aimed to understand the change rules of physicochemical properties of soil in the different modes of returning farmland to forest.[Method]The physicochemical properties of soil in three different types of returning farmland to forest(Hippophae rhamnoides Linn.forest,Caragana korshinskii forest and Ulmus pumila L.forest)were analyzed by taking the enclosed grassland as comparison in Bashang area of northern Hebei Province.[Result]The results showed that there were significant differences among different types.Order of the bulk density of soil:H.rhamnoides Linn.forest(1.17 g/cm^3)<U.pumila L.forest(1.24 g/cm^3)<C.korshinskii forest(1.26 g/cm^3)<enclosed grassland(1.61 g/cm^3);order of the total porosity of soil:H.rhamnoides Linn.forest(55.29%)>U.pumila L.forest(52.55%)>C.korshinskii forest(51.93%)<enclosed grassland(38.85%);order of the organic matter content of soil:H.rhamnoides Linn.forest(3.191%)>C.korshinskii forest(3.128%)>U.pumila L.forest(2.804%)>enclosed grassland(2.536%).[Conclusion]After returning farmland to forest,vegetation played a positive role in physicochemical properties of soil.There were significant differences in physicochemical properties of soil among different modes of returning farmland to forest,and the improvement effect of H.rhamnoides Linn.forest on physicochemical properties of soil was the best.

Estimation of Relative Ecological Value of Returning Farmland to Forest & Mountain Enclosure for Grazing Prohibition——A case study in Yongxing Township of Jingyuan County,Gansu Province

[Objective]Returning farmland to forest and mountain enclosure for grazing prohibition ecological effect and economy rationality were explored.[Methods]A case study of returning farmland to forest and barren hills grazing prohibition in Yongxing Township of Jingyuan County was used to discuss and estimate the relative ecological function and relative ecological value.[Results]1）The ecological value of the forest of returning farmland was far more than the sum of the ecological value of farm crops and the agricultural output,and also more than the national subsidy standard.So the state policy of returning farmland to forests is not only favorable to local eco-environment restoration,but also reasonable in economic development.2）The ecological value of mountain enclosure for grazing prohibition was less than the opportunity cost of prohibiting grazing,also less than the national subsidy standard.The sum of the relative ecological value of prohibiting grazing and the state subsidies was more than the opportunity cost of prohibiting grazing.However,the ecological value of new vegetation through returning farmland to forest project was greater than the China＇s average ecological value of grassland.[Conclusion]The relative ecological value can be used to solve the problems in the equivalent conversion among various ecological indexes and between ecological indexes and economic indexes.

Eco-environment Restoration and Regional Differentiation Characteristics Based on “Building Terrace and Returning Slope Farmland to Forests and Grass”

Based on the scientific and technological achievements in the past decade in the Loess Hilly-gully Region and the successful demonstration experience in Yan'an Yangou watershed, we summarize the characteristics of eco-environment restoration pattern based on "building terrace and returning slope farmland to forests and grass". According to the data on land use, slope farmland and the agricultural population in 1999, we calculate the area of new terrace that needs to be built, the area of garden plot that needs to be extended, vegetation restoration area and investment demand in counties (cities, districts). Establishing and using some indicators, such as basic farmland extension indicator, garden plot extension indicator, vegetation restoration index and investment demand density, we conduct type classification and analysis of regional differentiation characteristics in 55 counties (cities, districts). The results show that in the Loess Hilly-gully Region, 691 600 hm2 of new terrace needs to be built, 792 000 hm2 of economic forests and orchards need to be extended, 5 410 200 hm2 of vegetation needs to be restored, and the total investment demand is 15.82 billion yuan; in terms of geographical distribution, obviously there are two key areas for eco-environment restoration (one is located in the border area between northern Shaanxi and northwestern Shanxi, and the other is located in the eastern Gansu and southern Ningxia area); the classified regional guidance policies should be formulated as soon as possible, and the limited funds should be concentrated in the key areas.

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。

塔河胡杨林核心区退耕地初始年土壤及植被养分特征数值分析

【目的】研究塔河中下游胡杨林核心区退耕地初始年土壤和植被的养分特征,为胡杨林公益林核心区退耕地生态恢复提供基础支撑数据。【方法】以塔河中下游胡杨林核心区退耕地初始年的土壤和植被为研究对象,运用“S”形布点法、野外标准木全株收割法、多点混合方法分别采集植被和土壤样品,结合室内测定植被和土壤养分特征数值进行分析。【结果】(1)土壤养分含量和植被营养成分积累量均集中分布在Ⅳ区和Ⅴ区。(2)土壤垂直深度上,养分集中在表层土壤,且随着土层深度增加,土壤养分含量依次递减,但是在60~100 cm土层处,呈现小幅增加。不同样地与不同土层深度之间土壤养分含量差异显著(P<0.05)。(3)不同样地中残存棉花(棉秆、根系)及草本植物中全N、全P、全K、有机碳含量均有显著差异(P<0.05)。【结论】胡杨林自然保护区核心区退耕地初始年土壤养分含量较高,有利于荒漠植被群落的生长和发育,提高群落演替速率,有利于塔河胡杨林退耕地植被恢复与环境变化及其相互作用、生态过渡带植被恢复与区域生态稳定。

都匀市刺梨产业发展现状及对策探讨

于2023年4月对都匀市2013-2022年刺梨基地发展现状进行调查,了解基地抚育管理及挂果情况,并分析刺梨鲜果产量、销售及加工状况,总结刺梨产业发展存在困难、问题。结果表明:都匀市刺梨基地发展主要有3种方式,一是退耕还林(刺梨),其中以2017年造林面积最大;二是企业流转土地后纳入其他林业工程营造刺梨,以巩固退耕还林成果项目造林面积最大;三企业流转土地自己出资营造刺梨,主要集中在2015-2017年,造林面积达到8376亩。刺梨基地营建后普遍存在抚育管理次数少,挂果少问题。2019-2022年,刺梨鲜果产量呈逐年上升趋势,主要采收区为平浪镇、墨冲镇,销售则以个体户收购后倒卖外县刺梨加工厂为主。指出了都匀市刺梨产业发展存在诸多问题,如总体种植规模小、缺乏持续资金投入、后续抚育管理未跟上等,应结合刺梨产业发展现状及时作出调整。

新一轮退耕还林还草工程对土地利用效率的影响——基于黄河流域的实证研究

[目的]分析新一轮退耕还林还草工程实施对黄河流域土地利用效率的影响机制与政策效果,为深刻理解土地利用效率与持续推进退耕还林还草工程提供理论参考。[方法]以黄河流域新一轮退耕还林还草工程政策实施作为自然实验,采用包含非期望产出指标的Super-Window-DEA模型测度土地利用效率,采用双重差分模型与中介效应模型分析政策效果与传导途径。[结果](1)2009—2020年黄河流域69个城市的土地利用效率略有下降,上游(0.546 5)和下游(0.419 9)的土地利用效率高于中游(0.279 5);(2)新一轮退耕还林还草工程显著抑制了土地利用效率的提高,且政策的负向影响存在异质性,同时,经济发展和人口密度也分别促进和抑制土地利用效率;(3)耕地所占比例与财政支出是新一轮退耕还林还草工程影响土地利用效率的中介变量,且耕地比例是部分中介。[结论]建议在肥力较差、劳动力投入匮乏的土地上推进退耕还林还草工程,鼓励黄河流域各城市开展未利用土地的开荒复绿工作,后续退耕还林还草工程实施过程中根据流域之间土地利用的不同功能开展黄河流域上中下游之间、流域内城市之间的生态补偿,并充分借助信贷资金,引入生态产业化发展,推动绿色产业升级,探索退耕还林还草工程生态补偿的新模式。

灵宝市退耕还林工程阶段性监测与评价

对灵宝市退耕还林工程持续17年的效益监测表明:退耕还林工程的顺利实施,有效促进了工程区森林资源持续增长、粮食安全不断巩固、林业产值不断提升、退耕农户生活条件明显改善。

退耕还林补贴政策的实施状况与完善建议

文章以广西壮族自治区为调研对象,以其西南地区扶绥县为典型案例,采用实地调查、文献调查、对比分析等方法,重点分析了第二轮退耕还林补贴实施状况、成效与问题,以及在新形势、新要求下具体落实第三轮退耕还林补贴应做出的工作调整与措施改进。结果表明,由于实施退耕还林补贴,广西生态恶化趋势扭转、环境质量提高,林业产业结构改善,退耕农户实现增收;但政策实施也面临持续推进压力大、退耕还林成果巩固难、历史遗留问题多等困境,根源在于补贴地类有限、补贴标准偏低、补贴可持续性不足、政策整改办法不灵活等。在落实第三轮退耕还林补贴工作中,应强化资源调查、规划协调,优化补贴政策体系,调整整改措施,解决历史遗留问题,夯实新一轮补贴政策的落实基础,提高退耕还林成果巩固成效,促进退耕还林内生性发展。

多源土地利用/覆被产品在黄土高原应用和精度评估

为准确掌握黄土高原土地利用/覆被的时空格局,基于6种不同来源的土地利用/覆盖数据产品,MCD12Q1,ESA-CCI-LC,GlobeLand30,GLASS,CAS-LUCC和ChinaCover,开展了黄土高原地区退耕还林(草)实施以来土地利用/地表覆被时空格局和转类特征的研究,对不同来源数据产品的精度进行了验证分析。结果表明:(1)分类特征和变化趋势上,MCD12Q1和GLASS产品与其他产品的差异最大,其次为ESA-CCI-LC产品,GlobeLand30,CAS-LUCC和ChinaCover产品的差异相对较小。(2)除MCD12Q1产品外,不同来源土地利用/覆被产品各类型面积随时间变化趋势基本一致。(3)空间转类上,GLASS产品与其他产品的差异最大,解译类型明显错误;其次为MCD12Q1产品,转林类和转草类也存在明显错误,退耕还林(草)特征表现不明显;ESA-CCI-LC和GlobeLand30在黄土丘陵沟壑区退耕还林(草)的转类特征表现不足;CAS-LUCC和ChinaCover退耕还林(草)特征明显。(4)抽样精度上,GlobeLand30,CAS-LUCC,ChinaCover产品的总体精度最高,分别为86.61%(K=0.84),91.68%(K=0.90),89.45%(K=0.87);其次为ESA-CCI-LC(73.83%,K=0.69);MCD12Q1,GLASS产品的精度最低,分别为59.43%(K=0.51),36.31%(K=0.24)。(5)土地利用/覆被多源数据产品的融合有利于提高产品的精度,与融合前产品GlobeLand30,CAS-LUCC和ChinaCover相比,融合产品总精度可提高了2.25%~7.30%。综上,CAS-LUCC产品的精度最高,且2000—2010年退耕还林(草)表现与实际较为相符。

异质性人力资本对农户经济林经营行为的影响——基于退耕还林政策调节效应的分析

经济林兼具生态效益和经济效益,是我国生态建设、环境保护和乡村振兴中不可或缺的重要组成部分。文章结合农户个人禀赋和退耕还林政策两个方面,研究在农村劳动力迁移背景下人力资本与农户经济林经营行为的关系。基于2018-2019年在陕西省和四川省的实地调研数据,采用条件混合过程方法探究人力资本对农户经济林经营决策的影响及其作用机理。研究结果显示:(1)农户人力资本能够促进农户参与经济林经营,并呈现出倒U型的特点,拐点为7.98年。(2)退耕还林政策具有显著的正向调节作用,人力资本水平越高调节效果越强,参与退耕还林的农户拐点为9.18年,高于未参与农户的6.29年。(3)农户参与非农就业的收入效应较弱,替代效应并不显著,退耕还林政策在一定程度上弥补了该功能的缺失。人力资本对农户经济林种植具有促进作用,但是内生动力不足,因此现阶段我国农村经济林发展仍需政策引导。基于上述研究结论,本文给出政策启示:一是重视林业专业技术培训,加强人力资本对经济林产业的促进作用;二是加强政策引导作用,通过模范带动的方式,促进人力和资金投入经济林产业;三是增强市场服务和农机普及,以降低劳动力流失的影响。

黄土丘陵区刺槐林土壤团聚体稳定性和土壤可蚀性动态变化

退耕还林工程是黄土高原控制水土流失的主要措施之一,探讨退耕还林对土壤团聚体稳定性与土壤可蚀性的影响,可为黄土高原地区生态恢复和水土保持效益评价提供科学依据。以农田为对照,选取不同退耕年限(5,10,15,20,25,30年)刺槐林为研究对象,研究退耕还林后0—30 cm土层土壤团聚体稳定性和土壤可蚀性动态变化,并探讨土壤可蚀性与土壤团聚体稳定性之间的关系。结果表明:(1)>0.25 mm水稳性团聚体含量、平均重量直径、几何平均直径随着退耕年限增加呈递增趋势,三者相比退耕前(农田)分别增加32%~79%,32%~98%,2%~60%。(2)土壤团聚体分形维数随着退耕年限增加呈递减趋势,较退耕前减少0.6%~6.0%;土壤有机质随着退耕年限增加呈递增趋势,较退耕前增加8.4%~38.9%。(3)土壤可蚀性因子(K)随着土层增加而增加,但随退耕年限增加呈递减趋势,随退耕年限递增(K)分别减少1.0%,2.7%,3.6%,3.9%,5.0%,7.9%。(4)退耕还林后,>0.25 mm水稳性团聚体含量和土壤团聚体分形维数是土壤可蚀性变化的主要驱动因子;地上生物量通过影响>0.25 mm水稳性团聚体含量和土壤团聚体分形维数间接影响土壤可蚀性因子(K),且总效应最大。退耕还林后地上生物量增加对土壤团聚体的形成与稳定,以及土壤可蚀性降低起着重要作用,且退耕还林可显著提高团聚体稳定性,降低土壤可蚀性。

新一轮退耕还林对农户收入与消费的影响

以京津风沙源治理二期工程为例,采用随机效应模型和中介效应模型,分析研究了新一轮退耕还林对农户收入和消费的影响以及对消费的影响机制。结果表明:新一轮退耕还林显著增加农户总收入和经营性收入,但未显著改善农户收入结构;新一轮退耕还林显著增加农户总消费、基础性消费和生产性消费,但未显著优化农户消费结构;新一轮退耕还林通过增加农户收入这一中介变量对农户消费产生作用,经济效益显而易见。为进一步巩固退耕还林成果,政府应因地制宜提高补贴标准、整合细碎土地、推进林权改革、引导和鼓励农户多渠道增收与就业,内外双联动提升农民生活水平。

基于CiteSpace可视化分析的我国新一轮退耕还林工程发展脉络及展望

为进一步发掘新一轮退耕还林工程的研究热点及趋势,以新一轮退耕还林为主题,基于2012-2022年CNKI平台中的数据库,取300条样本,运用CiteSpace可视化分析的方法,深入解析我国新一轮退耕还林相关研究,包括研究机构合作网络、作者合作网络、关键词聚类图谱、关键词时区图谱和关键词突现图谱等方面。结果表明:(1)有关退耕还林的相关文献数量呈现先增加后下降的趋势。(2)有关我国新一轮退耕还林的研究文献主要围绕“后续产业”“农户收入”“生态效益”等问题展开,高频关键词显示新一轮退耕还林需要转变发展方式,要向高质量、可持续发展的方向转变,一味地扩大生态林规模并不可取。(3)退耕还林研究以对社会经济状况与初期退耕还林措施的综合改进分析为始发点,逐渐转变为以社会经济和生态效益的相互交织并存,并逐渐向以生态效益为主题逐步细分进行发展。所以,科研理念、方法之间的交融与并行以及怎样继续巩固和拓展退耕还林成果,如何合理的扩大退耕还林规模、保障农村环境安全、提高退耕农户增收,成为了今后科学研究发展的重要关键。

基于PMC指数模型的我国退耕还林还草专项政策量化评价

文中在梳理我国现行的退耕还林还草政策文件的基础上,借助Python软件并通过构建PMC指数模型对我国6份退耕还林还草专项政策文件进行量化评价。结果发现:1)2000-2008年我国退耕还林还草政策文件年均发布数量快速增加,这一时期发布的现行有效的政策文件占总有效文件的66.67%;2009-2020年政策文件年均发布量的变化相对较小,退耕还林还草政策体系逐渐健全成熟。2)依据PMC指数结果,将所选择的6份政策文件划分为完美、优秀、良好和可接受4个等级。其中,完美等级政策1份,优秀和良好等级分别为2份和3份。政策总体水平处在优秀等级,政策设计较为合理。3)对单项政策而言,有效的工作着力点能显著提高政策得分等级。此外,对政策的适时修订,多样化的政策措施和明确的政策目标可提高政策评分等级。4)现行政策内容突出了退耕还林还草的生态效益,而对工程的经济效益、科技创新主体的作用和价值的重视程度相对欠缺。据此,提出以下3条建议:1)退耕还林还草政策的制定应明确工作抓手,综合考虑退耕还林还草的生态、经济和社会效益;2)对政策内容进行适时调整;3)综合运用人事任免、财税支持、行政监管和信息引导等多种政策措施,并注意退耕还林还草的实际效果,量化政策目标。