Opportunity cost of water allocation to afforestation rather than conservation of natural vegetation in China

Estimation of ecosystem service values is a hot area of research in ecological conservation and economics. However, the costs of these outputs are largely unknown. In this paper, we estimated the opportunity cost of water allocated to afforestation projects through mathematical modeling based on statistical data for all of China to provide support for restoration planning based on a fuller consideration of the true costs. To guide future ecological conservation and environmental policy development, we illustrate a neglected concept (ecosystem service costs) and use this concept to compare the ecological services provided by ecological restoration based on afforestation with those of restoration based on the conservation of natural vegetation using data obtained since 1949 in China. The results showed that afforestation and natural vegetation create annual costs related to use of the available water resources equal to 4800 and 3700 RMB ha⁻¹, respectively, representing a water opportunity cost of 1100 RMB ha⁻¹ for afforestation. This illustrates the rule that “there is no free lunch” for any service, including ecosystem services. Therefore, to support the development of more effective and sustainable environmental restoration policy, it will be necessary to evaluate the associated opportunity costs.     

黄土高原植被建设中的问题与对策探讨

通过对黄土高原生态植被建设中存在的问题及其原因分析,提出了通过实行生态购买和实行林草的生态私有的利益驱动机制来调动农民的积极性,以达到生态效益和经济效益的双赢,同时应遵循自然规律,发掘生态功能强的植物种类,创建良好的混交植被结构,强化投入、管理和生态教育等相应对策来提高林草的覆盖率。     

黄土高原土地利用变化特征及其环境效应

研究目的:基于黄土高原近30余年来土地利用/植被覆盖变化(LUCC),分析该地区LUCC及其环境效应,为区域生态环境与社会经济的可持续发展政策提供科学依据。研究方法:地统计和趋势分析等。研究结果:(1)黄土高原土地利用结构整体上未发生变化,仍以草地、耕地和林地为主,但植被覆盖度提升显著;(2)黄土高原LUCC受气候变化和人类活动共同影响,影响程度存在区域性差异,其中黄土高原中部丘陵沟壑区主要由人类活动导致;(3)黄土高原LUCC对地表径流、土壤侵蚀、土壤水分及碳循环等生态环境过程将产生长期的影响,植被恢复在发挥生态效益的同时对区域生态环境产生消极的作用。研究结论:黄土高原植被生产力已接近水资源承载力阈值,提升人工植被稳定性、促进水资源平衡仍为现阶段促进黄土高原可持续发展的主要课题。     

Evaluation and simulation of the impact of land use change on ecosystem services trade-offs in ecological restoration areas,China

To restore China’s degraded environment and improve ecological balance, the government launched a land use policy known as the Grain for Green Program (GFGP), which is the largest ecological construction project in China or anywhere else. It has greatly increased the vegetation cover on the Loess Plateau but occupied the space of agricultural development (AD) over the years. Research on the impact of policy implementation on ecosystem services (ESs) and their trade-offs can support scenario analyses that provide realistic guidance for decision makers to formulate future regional ecological restoration planning. Our focus is Ningwu County and Jingle County on the Loess Plateau, a typical ecologically fragile and impoverished area where expansion of vegetation cover has driven extensive loss of farmland and its benefits to farmers.In this study, soil conservation (SC), water yield (WY), habitat quality (HQ), and food supply (FS) were selected to assess the change of ESs and their trade-offs in different scenarios that represent ecological restoration and land reclamation policies. The results revealed that overall ESs had the largest increase but there were more trade-offs among ESs under the GFGP scenario. For a single ESs, SC and HQ were increased while FS and WY were decreased under the GFGP scenario. From the view of trade-offs, the GFGP scenario exhibited more trade-offs than the AD scenario. Furthermore, compared to the GFGP scenario, the numbers of sub-watersheds with trade-offs of ESs decreased under the AD scenario. With more concern about the contradiction between implementing GFGP and protecting farmland, we confirm that it is extremely unwise to incessantly implement GFGP to improve overall ESs without considering the trade-offs among ESs. Given the certain sub-watersheds mainly developing agriculture, the AD scenario appears to best reduce trade-offs among ESs and ensure the improvement of ESs. Therefore, it is of great significance to realize the win-win situation of regional ecological and resource demand to find the most suitable development direction in the future.     

Effect of land-use conversion on C and N distribution in aggregate fractions of soils in the southern Loess Plateau,China

The purpose of this study was to assess the effect of grassland (GL) conversion to cropland (CL) and cropland conversion to forest (FL) and orchard (OL) on soil C and N distribution in dry aggregate size fractions in Nihegou catchment of the southern Loess Plateau, China. Four main land-use changes were analyzed in different agronomic management systems in 2006. The soil is wind-deposited loessial parent materials with a rather homogeneous silty clay loam texture classified as Calcic Cambosols. The GL was long-term over-used grassland. The CL was changed from GL after 33 years tillage with conventional tillage and fertilizer. The FL and OL originated from long-term CL after 23- and 7-year planted, respectively. Samples were taken at soil depths of 0–20 cm and 20–50 cm and were subjected to a physical fractionation process by way of aggregate size. Soil aggregate size fractions, total C and N contents and distributions were determined on all soil samples. Three dry aggregate fractions of very coarse (2.0–0.2 mm), coarse (0.2–0.05 mm) and fine (<0.05 mm) were obtained by shaking and sieving for 20 min. After 33 years of tillage, CL had 22% lower content of very coarse aggregates (2.0–0.2 mm) and 34% higher contents of fine aggregates (<0.05 mm) than GL. FL and OL soils had increased 9% and 10% contents of very coarse aggregates, and decreased 2% and 8% contents of fine aggregates compared to the CL. C and N losses in whole CL soils were 31% and 26% higher than those in GL. However, conversion of land uses from CL to FL (after 23 years) and OL (after 7 years) has increased C and N stocks by 76% and 40% in FL soils and by 66% and 63% in OL soils, respectively. This accessorial C and N stocks were higher in very coarse aggregate fractions (1.10 kg C m⁻² and 0.13 kg N m⁻² in FL soils, 1.43 kg C m⁻² and 0.17 kg N m⁻² in OL soils); moreover, the C and N stocks in fine aggregate fraction increased by 8% and 33% in FL soils and by 58% and 69% in OL soils, respectively. This results showed that C and N turnover and loss in aggregate fractions of this silty clay loam soils was very fast. Conversion of land uses from CL to FL and OL has obviously recovered the soil structure, and improved soil quality.     

黄土高原粮食生产潜力与增产配套技术

计算出黄土高原水土流失区各类粮食生产潜力,采用Ｈｅｌｍｕｎ ｌｉｅｔｈ估算式计算了全区粮食气候生产潜力。提出了粮食持续的战略对策。为正确指导粮食的区域平衡政策提供可靠的科学依据。     

Barriers and requirements to climate change adaptation of mountainous rural communities in developing countries: The case of the eastern Qinghai-Tibetan Plateau of China

Systematically identifying the barriers and requirements to adaptation is critical to the successful implementation of climate adaptation planning and policies at the local level, especially in the mountainous rural communities of developing countries with limited resources and technology. We conducted an empirical study of the barriers and requirements to adapting to climate change of 539 peasant households in an ecologically vulnerable area of China to enhance their resilience to climate change by improving our understanding of adaptation process and decision-making. Our findings indicated that farmers in the Gannan Plateau face multiple adaptation barriers, of which normative, information and technology barriers were more serious, such as lack of meteorological information service, infrastructure and technology extension in agriculture or animal husbandry. Adaptation requirements are an important way to effectively reduce or eliminate obstacles and improve farmers' adaptive capacity to climate change. The survey found that local households have an urgent requirement for infrastructure, information and production technologies, such as water, electricity, transportation facilities, disaster warning information, employment information and farming or breeding techniques. In addition, due to the influence of economic level, education level, years of farming, gender and other factors, differences exist in the adaptation barriers and requirements faced by farmers in different regions. These findings extend empirical evidence in favor of formulating a reasonable adaptation framework and choosing optimal adaptation strategies, which are essential for enacting well-targeted regional adaptation policies.     

模型模拟华北地区气候变化对冬小麦产量的影响

该文利用IPCC AR4模式资料和基于多年观测资料生成的格点数据,建立降水、最高/最低气温的统计降尺度关系,获取华北地区高分辨率未来气候情景空间分布;利用作物模型模拟IPCC-B1情景下冬小麦生长期和产量变化。结果表明:最高/最低气温模拟结果与观测值比较,相关系数(R2)大于0.70;降水模拟结果与观测值比较,相关系数最小为0.63;IPCC-B1情景下,华北地区冬小麦生长期总体上变短,产量下降。     

Determinants of climate change adaptation strategies and its impact on the net farm income of rice farmers in south-west Nigeria

A multivariate probit (MVP) model was used to analyse the determinants of strategies adopted for adapting to climate change in a sample of smallholder rice farmers in south-west Nigeria. An efficient endogenous switching regression model (ESRM) was used to estimate the impact of climate change adaptation strategy on the net income of rice farmers. The MVP results show that the socio-economic factors, the institutional factors, and locational variables of some households statistically influenced the choice of climate change adaptation strategies employed. Complementarities among all the adaptation strategies used by the farmers were revealed by the positive pair-wise correlation matrix of the MVP model. The study also indicated that farmers affected by prolonged drought and incidences of flood were more likely to adopt adaptation strategies on their farmlands. The ESRM treatment effect indicated that the average net income per rice farm of those who adopted the strategies was significantly higher than that of those who did not. Thus, the government, stakeholders, and donor agencies must provide capacity-building innovations related to agricultural extension systems and climate change education through information and communication technologies. This investment in education is essential for development and would encourage farmers to adopt appropriate climate change adaptation strategies.     

Detecting the impact of the “Grain for Green” program on the mean annual vegetation cover in the Shaanxi province, China using SPOT-VGT NDVI data

In order to reduce the soil erosion rate on the Chinese Loess Plateau, the Chinese government launched in 1999 the “Grain for Green” program (GfG). The objective of this program was to increase the forest cover on steep slopes in the landscape by planting trees and sowing grasses on former cropland. The program was a massive investment by the Chinese government. By the end of 2005 the GfG-program was implemented in an area of 87,000 km² in which about 400–600 million trees were planted. At present it is not known to what extent this program was successful. This paper examines the effects of the GfG-program on the mean annual vegetation cover in the Shaanxi province. A decadal time series of SPOT VEGETATION imagery from 1998 till 2005 were used to calculate NDVI-values in four counties with different rainfall regimes. By means of a regression between preceding rainfall and NDVI-values the effects of rainfall variability were filtered out. A trend analysis of the corrected NDVI time series pointed out that the GfG-program resulted in a significant increase of the vegetation cover on farmland in the northern part of Shaanxi province. In the southern part of the province, which has a more humid climate and large areas of irrigation farmland no significant increase of the vegetation cover on farmland could be detected.     

Forest carbon benefits,costs and leakage effects of carbon reserve scenarios in the United States

This study evaluated the potential effectiveness of future carbon reserve scenarios, where U.S. forest landowners would hypothetically be paid to sequester carbon on their timberland and forego timber harvests for 100 years. Scenarios featured direct payments to landowners of $0 (baseline), $5, $10, or $15 per metric ton of additional forest carbon sequestered on the set aside lands, with maximum annual expenditures of $3 billion. Results indicated that from 1513 to 6837 Tg (Teragrams) of additional carbon (as carbon dioxide equivalent, CO₂e) would be sequestered on U.S. timberlands relative to the baseline case over the next 50 years (30–137 Tg CO₂e annually). These projected amounts of sequestered carbon on timberlands take into account projected increases in timber removal and forest carbon losses on other timberlands (carbon leakage effects). Net effectiveness of carbon reserve scenarios in terms of overall net gain in timberland carbon stocks from 2010 to 2060 ranged from 0.29 tCO₂e net carbon increase for a payment of $5/tCO₂e to the landowner (71% leakage), to 0.15 tCO₂e net carbon increase for a payment of $15/tCO₂e to the landowner (85% leakage). A policy or program to buy carbon credits from landowners would need to discount additions to the carbon reserve by the estimated amount of leakage. In the scenarios evaluated, the timber set-asides reduced timberland area available for harvest up to 35% and available timber inventory up to 55%, relative to the baseline scenario over the next 50 years, resulting in projected changes in timber prices, harvest levels, and forest product revenues for the forest products sector.     

The adoption and impact of engineering‐type measures to address climate change: evidence from the major grain‐producing areas in China

Employing an endogenous switching regression model, we investigate the drivers underlying the adaptations made by farm households and their impacts on crop net incomes for adopters and nonadopters, based on a large panel survey data set across the major grain‐producing provinces in China. The results show that: (i) access to public climate information and technical or physical support increases the likelihood that farmers adapt to climate change by undertaking irrigation and/or drainage measures; and (ii) decisions to adapt increased crop yield, but they did not significantly increase crop profit margins. This point appears to have been ignored by previous studies. Based on these new empirical results, the paper suggests that government should continue to provide climate information and various types of supports to improve farmers’ adaptation abilities and help to reduce the levels of factor input by, for example, substituting organic for chemical fertiliser inputs. Such government‐led policies should be supported alongside the implementation of domestic agricultural supply‐side reform.     

The effects of the Yuan‐dollar exchange rate on agricultural commodity trade between the United States,China, and their competitors

The United States claims that the undervaluation of Chinese currency, the Yuan, causes U.S. exports to China to decrease and imports from China to increase. Furthermore, because the Yuan is undervalued only against the dollar, U.S. competitors have an advantage in exporting to China and China has an advantage over its competitors in exporting to the United States. This study develops a theoretical model to analyze the effect of the Yuan undervaluation on prices, supply, demand, and trade in the United States, China, and their competitors. This study applies a cointegration/error‐correction model to empirically quantify the short‐run and long‐run effects of the devaluation of the Yuan on important agricultural commodities traded between the United States, China, and their competitors. These commodities include Chinese imports of milk, soybeans, and cotton from the United States and U.S. imports of beans, fruit juice, and fruit from China. The results show that Yuan devaluation causes Chinese imports of U.S. milk, soybeans, and cotton to decline and U.S. imports of beans, fruit juice, and fruit from China to increase in the short run and in the long run.     

Urban sprawl and climate change: A statistical exploration of cause and effect,with policy options for the EU

This study provides a brief evaluation of the relationship between trends in transport emissions and urban land-use by analysing correlation between transport CO₂ emissions data, GDP and population data with land-use change data from the CORINE database for EU Member States between 1990 and 2000.     

国家--农民关系的新建构:以建国初期中南区的查田定产为中心

查田定产是国家与农民关系的一次新建构，它不仅影响到土改中阶级的划分，而且还使新生的国家全面掌拉了土地资源，确立了向农民征收农业税的依据，并为合作化运动中土地入社以及包工包产的推行奠定了基础。本文考察了建国初期中南区查田定产的推行概况、推行方法和组织领导机构，分析了查田定产的源起、影响以及不足。     

中国南方水稻干旱的解决途径探讨——对政府部门、科研

概述中国南方水稻种植面临的干旱问题，报告对有关政府部门、科研机构和农户调查的简况、政府部门和科研机构以及农户采取的抗旱措施，同时比较了各有关方面对干旱解决途径的看法，为解决中国南方水稻干旱问题，提出建议：加强中国南方水利设施的修建和管理、关注耐旱水稻品种的培育、加快农技推广体系的改革和建立完善的农技推广体系。     

The effects of farmland use rights trading and labor outmigration on the governance of the irrigation commons: Evidence from China

The governance of the commons depends on collective action by resource users, which may be influenced by land use dynamics and changes in livelihood. We examine the case of China that has experienced massive outmigration of its rural population and significant changes to its land use policy. We contribute to the literature by examining the interaction effects of farmland use rights trading and rural labor out migration on collective action for the governance of the irrigation commons, which has the potential to open up a new line of theoretical and empirical inquiry. Using the socio-ecological system framework, we run ordered probit regression based on data from a survey of 125 villages in 18 provinces in China. We find that a moderate degree of farmland use rights trading has a positive effect on collective action for the governance of the irrigation commons and can slow down and mitigate the negative effect of rural labor outmigration. We conclude with implications for land use policy and governance of the commons.     

Conservation Payments, Liquidity Constraints, and Off-Farm Labor: Impact of the Grain-for-Green Program on Rural Households in China

This study evaluates the labor response of rural households participating in the Grain-for-Green program in China, the largest payments for ecosystem services program in the developing world. Using a panel data set that we designed and implemented, we find that the participating households are increasingly shifting their labor endowment from on-farm work to the off-farm labor market. However, the effects vary depending on the initial level of human and physical capital. The results support the view that one reason why the participants are more likely to find off-farm employment is because the program is relaxing households' liquidity constraints.     

Assessing impact of land uses on land salinization in the Yellow River Delta,China using an integrated and spatial statistical model

Intensification of agriculture and industry in salinized areas poses a risk of secondary salinization. Thus, comprehensive and spatially explicit assessments are needed to assist government in developing ecologically sound policies. Few assessments have comprehensively quantified the impacts of multiple anthropogenic activities on salinization as environmental interferences and salinity autocorrelation are largely neglected. This study tried to perform such an assessment by identifying the nature of human impacts on salinization from three aspects in the Yellow River Delta (YRD) of China. A versatile GIS-based spatial autoregression (SAR) was applied to nine selected explainable variables in six sub-region models. Sub-region model was verified as an effective tool of normalizing environmental interferences because more useful spatial information was provided compared to the whole region model. GIS-SAR model fit better and performed better in quantifying human activities, compared to the conventional ordinary least square regression (OLSR) model, as SAR can deal with spatial autocorrelation in soil salinity. Among the well-defined key determinants, oil exploitation and saline aquaculture were aggregative to salinization but only in originally highly saline sub-regions, such as coastal zone and Gleyic Solonchaks (coastal saline moisture soil) area. Two agricultural activities, crop plantation and fertilization, were mainly ameliorators in most sub-regions. The most effective salinization alleviation occurred in moderately saline sub-regions, such as floodplain and Salic Fluvisols (saline moisture soil) area, which benefitted from the development of agroforests and farm ponds. The SAR sub-region model is spatially explicit for spotting the hazardous areas and some suggestions were also provided for the policy makers.     

发展竞争、土地供应策略互动与城市用地增长——基于252个城市数据的空间面板模型实证检验

研究目的：针对发展竞争驱动下产生的地方政府土地供应策略,从空间维度上展开进一步分析,解析城市土地供应行为中存在着怎样的空间互动关系。研究方法：运用2007—2017年的城市层面面板数据和空间计量模型进行了实证检验。研究结果：（1）服务于发展竞争的土地供应策略,对本城市和周边城市的用地增长都会产生影响;（2）工业用地价格波动与商住用地价格波动都会产生空间溢出效应,且前者产生的空间溢出效应更强;（3）工业用地价格存在“竞次式”的城市间互动,其价格增长会显著抑制本城市的用地扩张,但会促进周边城市的用地增长;（4）商住用地价格提升会促进本城市用地扩张,并抑制周边城市用地扩张;（5）作为因变量的城市用地规模,在同省/异省的城市间分别存在着“彼此促进”和“此消彼长”两种互动关系。研究结论：区域协调、用地增长两个方面要紧密结合,针对工业用地价格“竞次式”竞争和商住用地价格高价出让,从城市间关系协调入手进行调控政策的设计与创新。