Responses of vegetation cover to the Grain for Green Program and their driving forces in the He-Long region of the middle reaches of the Yellow River

The implementation of the Grain for Green Program is a great breakthrough in the history of China＇s ecological environment construction,which can control soil erosion effectively,increase land productivity and improve the ecological environment.To investigate the eco-environmental benefits brought by the Grain for Green Program,the spatiotemporal variations of vegetation cover in the growing season from 2000 to 2010 across the Hekou-Longmen （He-Long） region were analyzed by using remote sensing information,meteorological data and land use data.Moreover,the impacts of climate and human activities on vegetation change were evaluated objectively.Annual vegetation cover in the growing season increased very significantly.Increased vegetation cover occurred in 98.7％ of the region,of which the area for vegetation cover improved slightly constituted 79.8％ of the whole area.Vegetation moderately improved was mainly distributed in the south of the He-Long region,covering 9.6％ of the area,and the area for vegetation basically unchanged concentrated in the middle and upper reaches of the Wuding River.Precipitation was found to be an important natural factor influencing vegetation cover change.The area of vegetation cover showing a significantly positive correlation with precipitation occupied 22.14％ of the region.As driven by policies from the Grain for Green Program,forestland increased significantly and land use structure became more intensive.Human activities played a positive and effective role in the protection,restoration and improvement of vegetation in the places where vegetation cover was basically unchanged,even though precipitation declined greatly,and vegetation improved moderately with massive increases of forestland and grassland.

Changes in Land Use and Agricultural Production Structure Before and After the Implementation of Grain for Green Program in Western China–Taking Two Typical Counties as Examples

Soil erosion becomes a serious environmental problem in the world, especially in western China. An effective management practice called the Grain for Green Program(GGP), which was launched in 1999, aims to reduce soil and water loss and alleviate the ecological environment problem in western China. Two typical counties in western China, the Zhongxian(in Chongqing Municipality) and Ansai(in Shaanxi Province) were chosen to evaluate the dynamic changes of land use and agricultural production structure before and after the implementation of the Program in this paper. The results showed that the cultivated land area was reduced by 7.08% from 1989 to 2003. The cultivated land per person was decreased by 8.42% during 1999-2003. Moreover, the stability index of the secondary sector of the economy was increased from 0.91 in the period 1990-1999 to 0.94 in the following ten years. In addition, the stability index of tertiary economic sector increased from 0.88 to 0.92 in Zhongxian county. Meanwhile, the cultivated land area was reduced by 15.48% from 1990 to 1999. The soil erosion modulus was decreased by 33.33% from 1999 to 2006. Also, the stability index of secondary and tertiary economic sectors was 0.86 in the period 1998-2002. However, it decreased by 77% during 2002 to 2007 in Ansai County. These results imply that the Grain for Green Program had different impact on the two regions. Several effective strategies of soil and water conservation have been carried out to ameliorate the sustainable development of ecological environment and economy in these two counties of western China.

Coupling between the Grain for Green Program and a household level-based agricultural eco-economic system in Ansai,Shaanxi Province of China

The implementation of the Grain for Green Program(GGP)has changed the development track of the agricultural eco-economic system in China.In response to the results of a lag study that investigated the coupling between the GGP and the agricultural eco-economic system in a loess hilly region,we used a structural equation model to analyze the survey data from 494 households in Ansai,a district of Yan’an City in Shaanxi Province of China in 2015.The model clarified the direction and intensity of the coupling between the GGP and the agricultural eco-economic system.The coupling benefits were derived through linkages between the program and various chains in the agricultural eco-economic system.The GGP,the agroecosystem of Ansai and their potential coupling effects were in a state of general coordination.The agroecosystem directly affected the coupling effect,with the standardized path coefficient of 0.87,indicating that the agroecosystem in Ansai at this stage provided basic material support for the coupling between the GGP and the agricultural eco-economic system.The direct path coefficient of agroeconomic system impacted on the coupling effect was-0.76,indicating that partial contradictions occurred between the agroeconomic system and the coupling effect.Therefore,although the current agroecosystem in Ansai should be provided sufficient agroecological resources for the benign coupling between the program and the agricultural eco-economic system,agricultural development failed to effectively transform agroecological resources into agricultural economic advantages in this region,which resulted in a relative lag in the development of the agricultural economic system.Thus,the coupling between the GGP and the agricultural eco-economic system was poor.To improve the coupling and the sustainable development of the agricultural eco-economic system in cropland retirement areas,the industrial structure needs to be diversified,the agricultural resources(including agroecological resources,agricultural economic resources and agricultural social resources)need to be rationally allocated,and the chain structure of the agricultural eco-economic system needs to be continuously improved.

Trade-offs and Synergies of Ecosystem Services in Karst Area of China Driven by Grain-for-Green Program

As an important means regulating the relationship between human and natural ecosystem,ecological restoration program plays a key role in restoring ecosystem functions.The Grain-for-Green Program(GFGP,One of the world’s most ambitious ecosystem conservation set-aside programs aims to transfer farmland on steep slopes to forestland or grassland to increase vegetation coverage)has been widely implemented from 1999 to 2015 and exerted significant influence on land use and ecosystem services(ESs).In this study,three ecological models(In VEST,RUSLE,and CASA)were used to accurately calculate the three key types of ESs,water yield(WY),soil conservation(SC),and net primary production(NPP)in Karst area of southwestern China from 1982 to 2015.The impact of GFGP on ESs and trade-offs was analyzed.It provides practical guidance in carrying out ecological regulation in Karst area of China under global climate change.Results showed that ESs and trade-offs had changed dramatically driven by GFGP.In detail,temporally,SC and NPP exhibited an increasing trend,while WY exhibited a decreasing trend.Spatially,SC basically decreased from west to east;NPP basically increased from north to south;WY basically increased from west to east;NPP and SC,SC and WY developed in the direction of trade-offs driven by the GFGP,while NPP and WY developed in the direction of synergy.Therefore,future ecosystem management and restoration policy-making should consider trade-offs of ESs so as to achieve sustainable provision of ESs.

Impacts of Drought and Human Activity on Vegetation Growth in the Grain for Green Program Region,China

The Chinese government adopted six ecological restoration programs to improve its natural environments. Although these programs have proven successful in improving local environments, some studies have questioned their performance when regions suffer from drought. Whether we should consider the effects of drought on vegetation change in assessments of the benefits of ecological restoration programs is unclear. Therefore, taking the Grain for Green Program(GGP) region as a study area, we estimated vegetation growth in the region from 2000–2010 to clarify the trends in vegetation and their driving forces. Results showed that: 1) vegetation growth increased in the GGP region during 2000–2010, with 59.4% of the area showing an increase in the Normalized Difference Vegetation Index(NDVI). This confirmed the benefits of the ecological restoration program. 2) Drought can affect the vegetation change trend, but human activity plays a significant role in altering vegetation growth, and the slight downward trend in the NDVI was not consistent with the severity of the drought. Positive human activity led to increased NDVI in 89.13% of areas. Of these, 22.52% suffered drought, but positive human activity offset the damage in part. 3) Results of this research suggest that appropriate human activity can maximize the benefits of ecological restoration programs and minimize the effects of extreme weather. We therefore recommend incorporating eco-risk assessment and scientific management mechanisms in the design and management of ecosystem restoration programs.

Decomposition dynamics and ecological stoichiometry of Quercus acutissima and Pinus densiflora litter in the Grain to Green Program Area of northern China

Litter decomposition and ecological stoichiometry of nutrient release is an important part of material cycling and energy flow in forest ecosystems.In a study of the ecological stoichiometry and nutrient release during litter decomposition in a pine–oak forest ecosystem of the Grain to Green Program(GTGP)area of northern China,a typical pine and oak species(PDS:Pinus densiflora Sieb.,QAC:Quercus acutissima Carr.)were selected in the Taiyi Mountain study area.The ecological stoichiometry characteristics of carbon(C),nitrogen(N)and phosphorus(P)and litter decomposition dynamics were studied by field sampling and quantitative analyses.The results showed the following.(1)The decomposition dynamics of both litters was slow-fast-slow.The most important climatic factor affecting the litter decomposition rate from May to October was precipitation and temperature from November to April of the following year.(2)Throughout the 300-day study,in both litters,C of the two litters was released,N first accumulated and was then released,and P exhibited a release-accumulate-release pattern.(3)C:P was significantly higher than C:N and N:P(p<0.05);the C:N of PSD litter was higher than that of QAC(p<0.05),but the N:P of QAC litter was higher than that of PSD litter(p<0.05).The C:N of both litters was very high in the study area,indicating that the nutrient release ability during litter decomposition in the two typical pine–oak forest ecosystems was relatively weak;therefore,more attention should be paid to nitrogen-fixing species and mixed forests in the GTGP area of northern China.

Trade-off analyses between food provision and soil conservation service of Grain for Green Program in Mountainous Area

The Grain for Green Program and soil and water conservation engineering initiatives are crucial for controlling erosion in steep-slope agriculture.However,it is still unclear how these two management methods should be carried out in respect to the situation in mountainous areas.Therefore,taking a typical mountainous area in southwest China as an example,we simulated six scenarios in order to compare the food provisioning service(FPS)and soil conservation service of the Grain for Green Program(converting to grassland)and Construction Measures(converting to sloping terrace)under different slopes.Results showed that when farmland with a>25°slope was converted into grassland,the amount of soil erosion(M)decreased by 21.0%,while FPS decreased by only 0.7%.However,when farmland with a>25°slope was converted into sloping terrace,M decreased by 31.3%while FPS increased by 18.7%.With the increases of farmland slope ranges in the Construction Measures scenario,M gradually decreased and FPS gradually increased.Particularly when farmland>15°was converted into sloping terrace,M decreased by 63.9%and FPS increased by 52.7%.Furthermore,the trade-offs of Construction Measures are lower than that of Grain for Green on different slope ranges.Therefore,we conclude that Construction Measures are a more suitable method in mountainous areas than the Grain for Green,and we suggest that further research be conducted to consider the ecological risks of construction engineering measures.

Issues and Challenges in Implementing China’sGreen Public Procurement Program

Sustainable development and environmental protection are the themes of the day. One popular policy tool that government uses to promote sustainable development and to protect the environment is green public procurement. Chinese government established its public procurement system in the late 1990s. It has moved to implement green procurement since 2004. In this paper, the authors will first trace the development of Chinese green public procurement program. The authors will then examine the issues involved in its implementation and make suggestions as to how to make green public procurement program more effective. This is one of the first papers examining China’s green public procurement program.

Effect of the Grain for Green Project on freshwater ecosystem services under drought stress

The Grain for Green Project(GGP) is an important measure for the prevention of sloping farmland and the restoration of natural vegetation.This project has been critical to the restoration of ecological environments in western China. However,the effect of the GGP on freshwater ecosystem services under extreme climates remains unclear. Thus, taking the middle and upper reaches of the Wujiang River Basin in western China as an example, this study assessed the variation of three freshwater ecosystem services(e.g., water yield, soil retention and nutrient retention) impacted by the GGP under drought stress by employing the Integrated Valuation of Ecosystem Services and Tradeoffs(In VEST) model. In addition,the trade-off/synergistic relationship between three freshwater ecosystem services was analyzed based on the Pearson correlation coefficient. As revealed from the results, the effect of the GGP on the water yield and nutrient retention under drought stress was significantly higher than that on the soil retention.With the increase in the drought degree, the variation rate of the water yield and nutrient retention impacted by the GGP increased, whereas that of the soil retention decreased. The GGP in droughts of different seasons resulted in a significant heterogeneity in the changes of three freshwater ecosystem services. The correlation coefficients between the water yield and soil retention as well as that between the water yield and the nutrient retention increased, and the correlation coefficients declined between soil and nutrient retention under different drought degrees following the GGP. Unlike for the summer drought case, there were no significant changes in the correlation coefficients between three freshwater ecosystem services in spring, autumn and winter droughts. The results suggest that the amount of farmland converted to shrubland should be regulated to reduce the trade-off intensity between freshwater ecosystem services. In addition, food security and ecological environment protection should be balanced during the implementation of the GGP, and the most concentrated distribution region of farmland-to-forest conversion will be the key area of ecological management in the future.

Green resource allocation for mobile edge computing

We investigate the green resource allocation to minimize the energy consumption of the users in mobile edge computing systems,where task offloading decisions,transmit power,and computation resource allocation are jointly optimized.The considered energy consumption minimization problem is a non-convex mixed-integer nonlinear programming problem,which is challenging to solve.Therefore,we develop a joint search and Successive Convex Approximation(SCA)scheme to optimize the non-integer variables and integer variables in the inner loop and outer loop,respectively.Specifically,in the inner loop,we solve the optimization problem with fixed task offloading decisions.Due to the non-convex objective function and constraints,this optimization problem is still non-convex,and thus we employ the SCA method to obtain a solution satisfying the Karush-Kuhn-Tucker conditions.In the outer loop,we optimize the offloading decisions through exhaustive search.However,the computational complexity of the exhaustive search method is greatly high.To reduce the complexity,a heuristic scheme is proposed to obtain a sub-optimal solution.Simulation results demonstrate the effectiveness of the developed schemes.

Partnership in the Community“Going Green”Program

On the lawns and central garden of a community in the Haidian District of Beijing, called ＂Enjili＂, one can see a number of signs with the ＂Michelin＂ logo standing as tall as a man.

Cultivated-land change in Mu Us Sandy Land of China before and after the first-stage grain-for-green policy

Mu Us Sandy Land(MUSL) of China, as a typical eco-fragile and farming-pastoral transitional region, shows great vulnerability to disturbances from cultivation activity. In this region, the conflict between cultivation activity and environmental protection has not attracted great importance until the implementation of China's Grain-for-Green Policy(CGGP) since2000. Here, using Landsat5 TM/Landsat7 ETM+ images from 1990, 2000, and 2010, we monitor the cultivation activity and land-use/cover changes(LUCC) resulting from cultivation activity in the MUSL region. Based on the data from images, we developed a series of databases of cultivated activity-induced LUCC and use them to discuss comparatively the spatio-temporal evolution trends of cultivation activity before and after CGGP implementation. These results provide evidence for managers to evaluate the implementation effectiveness of governmental policy and the influence of cultivation activity on the ecological environment of the MUSL region.

风光制氢合成氨系统的多时段可调度域分析

为直观描述风光发电制氢合成氨(power-to-ammonia,P2A)系统的柔性负荷调节潜力,计及制氢、合成氨化工过程的负载调控特性,基于动态规划思想和计算几何理论,提出其多时段可调度域(multi-stagedispatchableregion,MSDR)的刻画方法。所提方法将多时段间相互耦合的鲁棒约束变换为“氢缓冲罐贮量–合成氨产率”状态空间中的确定性多面体约束,使得对于可调度域内的任意系统状态,均存在满足完整调度过程安全约束的“制氢流量–氨产率爬坡速率”控制序列,从而实现P2A系统可调度能力的可视化。所提MSDR模型可进一步用于构造多时段鲁棒优化调度,在保证可行性的前提下优化P2A系统的经济收益。最后,基于内蒙古自治区某在建示范工程构造算例,验证所提方法的有效性。

“千万工程”经验助推乡村建设的历史逻辑与实践路径

“千万工程”成功推进了浙江整省全域的乡村振兴,对于当下推进乡村建设工作具有重大的指导意义:第一,“千万工程”经验具有深厚的历史逻辑,它继承并创新了马克思主义经典作家的论断和党在乡村建设中的宝贵经验,传承并发展了中华五千年乡村建设史中的优秀传统,总结了世界乡村建设的普遍规律和经验教训,并在自身21年的实践史中不断自我完善,展示了强大的包容性和旺盛的生命力。第二,“千万工程”明确了乡村建设的目标原则,对于破除当前乡村建设中忽视农民主体地位、破坏生态环境、无视历史传承等问题具有重要的警示意义,为我们解答了“建设什么样的乡村”的重要问题。第三,各地在推广运用“千万工程”经验的实践中,必须坚持久久为功、量力而行和因地制宜的原则,不能将“千万工程”视为一种刻板的教条,而要深刻参悟其中蕴含的理念方法和价值取向。

2024年中央一号文件的突出亮点

2024年中央一号文件以习近平新时代中国特色社会主义思想为指导,为2024年乃至今后一段时期的“三农”工作进行了系统部署和具体安排,呈现了一系列突出亮点。即:凸显了贯彻中央经济工作会议精神和深化对“三农”工作的规律性认识,明确了学习运用“千万工程”经验引领乡村全面振兴的要求,重视运用战略思维和改革创新,统筹强化软政策引领与硬政策支撑作用,坚持守正创新,确保国家粮食安全有新招,确保不发生规模性返贫底线更明确措施更有力,强调以坚持“三个提升”为重点建设宜居宜业和美乡村。

昆虫对低氧环境的适应性机制研究进展

昆虫需要利用氧气进行有氧呼吸,产生能量,维持正常的生命活动。在储藏环境中,可以利用气调技术控制环境中氧气的占比,以达到防治害虫的目的。然而害虫低氧适应性的发展为这项技术的推广和应用带来挑战。文章围绕低氧对昆虫生长发育、生命活动、生理功能的影响,以及昆虫适应低氧环境的补偿性策略,包括内在调控机制,生物学特性调节,代谢网络重构,基因调控等方面进行了综述。以期为害虫低氧适应性的产生机制提供新的研究线索,为绿色储粮技术的研究及发展提供参考。

生产集聚对粮食生产用水绿色效率的影响研究--以我国粮食主产区为例

基于2002-2021年我国13个粮食主产区的省级面板数据,运用区位基尼系数和Super-SBM模型对粮食主产区粮食生产集聚度和粮食生产用水绿色效率分别进行测度,在此基础上通过面板模型探究粮食生产集聚对粮食生产用水绿色效率的影响,并利用中介效应模型对路径机制进行检验。结果表明:研究期内我国粮食主产区粮食生产集聚度整体呈上升趋势,粮食生产用水绿色效率呈现“北高南低”的空间分布状态且整体无明显改善。粮食生产集聚度与粮食生产用水绿色效率呈“倒U形”关系,规模化经营和种植结构调整在“倒U形”关系中发挥中介效应且规模化经营的中介效应更大,科技创新的中介效应不显著。因此政府应因地制宜制定合理的粮食生产集聚政策,引导农户、组织及企业适度规模经营,提高种植结构的合理性,建立粮食生产集聚与技术创新的高效联动机制,促进粮食生产用水绿色效率的提升。

绿色金融赋能主产区粮食生产的高质量发展双效应研究

粮食主产区以粮食生产为中心,被赋予国家粮食安全的重大责任和率先推进农业农村现代化的艰巨任务,必须加快主产区粮食生产的高质量发展。基于此,构建以粮食生产为中心的经济循环系统理论分析框架,利用2012—2021年省级面板数据,采用固定效应、中介效应和门槛效应模型,实证检验绿色金融赋能主产区粮食生产的高质量发展“双效应”。结果显示,绿色金融赋能一方面通过粮食生产的要素改造、行为转变和产品升级产生直接效应,另一方面通过消费市场粮食产品生态化和价值化导向需求响应行为产生间接效应。研究表明,绿色金融赋能粮食生产高质量发展既具有金融工程的项目性质,可以利用不同的绿色金融工具实施;又具有区域经济系统的整体性和复杂性,需要利用不同的绿色金融工具组合及其功能创新才能实现,以防止和规避主产区以粮食生产为中心的经济循环“梗阻”现象。

“千万工程”与促进长三角地区共同富裕逻辑研究

党的二十大报告指出,中国式现代化是全体人民共同富裕的现代化。理清土地综合整治、“千万工程”与共同富裕之间存在的逻辑关系,对于探索长三角地区共同富裕差距及其成因、探究通过土地综合整治深化“千万工程”来促进长三角地区共同富裕的基本思路与路径具有重要意义。研究发现,土地综合整治与“千万工程”之间存在相辅相成的关系,共同富裕是二者的最终目标,构建共富单元则是实现共同富裕的有效途径。长三角地区内部及其省市之间的共同富裕差距主要由区位条件、资源禀赋、生态环境等因素的差异造成。在追求共同富裕和城乡一体化的背景下,应以高质量供给引领创造新需求为主线,基于土地综合整治和“千万工程”建设,推动国土空间资源要素配置与共同富裕现代化生产力布局优化相适应,在全域打造共同富裕现代化基本单元;推动“山水林田湖草”综合治理和“产城人文景生”融合发展,推进区域治理水平提升。

浙江省未来乡村建设评价与分类优化策略研究——以浙江临海市为例

建设未来乡村是浙江省政府为持续深化“千万工程”、促进农民农村共同富裕提出的新时期发展目标。开展未来乡村建设评价则是引导明确未来乡村建设方向、建立常态化考评机制、推动工作落实落地的重要依据。本文以浙江省临海市为例,综合省政府指导意见和临海市乡村发展现状,从安全、宜居、共富、和美、人文、数治6个维度构建未来乡村建设评价体系,以临海市行政村调研问卷、统计资料和实地考察数据为依托开展未来乡村建设评价,基于评价结果将临海市未来乡村建设类型分为文旅特色型、补齐短板型、综合发展型3个大类,并分别针对各类型乡村建设短板提出优化指引策略。研究成果可为深化推进临海市未来乡村建设工作、总结凝练浙江省未来乡村建设评价区域模式提供借鉴和参考。