Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.     

School food environments and the obesity issue: content,structural determinants,and agency in Canadian high schools

To understand the phenomenon of the rapidly increasing prevalence of overweight and obese children and youth, it is especially important to examine the school food environment, the role of structural factors in shaping this environment, and the resulting nutrition and health outcomes. The paper examines research on school food environments in the US and Canada. It notes evidence of widespread availability of poor nutrition products in both environments and delineates reasons for the situation, and examines initiatives presently being undertaken in a number of jurisdictions in both countries to encourage healthy eating in schools. Empirical data are presented from a pilot study of high schools in the Canadian province of Ontario. The study documents the extent of student purchasing of nutrient-poor foods and beverages, and the structural factors internal and external to the school that appear responsible for the availability of such products in food environments in this critical institutional sphere. The paper also examines positive local initiatives in high schools that seek to encourage healthy eating in schools.

中国渔业“大国效应”特征、战略选择及其政策建议

中国是渔业大国,但与其他渔业大国相比,存在显著不同的发展环境、条件和特点。本文在以往讨论我国渔业大国的基础上,综合学者的研究成果,以大国效应为视点,讨论我国渔业大国现象特征、研究其规律;归纳分析了秘鲁、日本和前苏联等渔业大国的优势陷阱;对我国渔业战略发展提出积极运用渔业大国效应、保持领先发展战略的政策建议。     

美国公共放牧地管理政策演进的历史经验

当初步遏制草地退化后,我国当前迫切需要对草地管理政策进行优化和调整,进而更好地通过草畜平衡和生态补贴实现生态保育和牧民利益的协调和可持续发展目标。长达90年的美国公共放牧地政策可以为我国调整和优化草地管理政策提供借鉴。美国经验表明,实现草地生态保育需要在社会共识、法律体系和行政管理等方面,牢固地树立和实现草地的多重功能和生态系统服务理念。进一步地,公有的草地产权制度是保障草地多重生态系统服务的法律前提,非牧产业发展是实现草地多重功能的经济基础,精细的行政管理是实现草地生产生态平衡的技术保障,多种利益主体参与是实现草地管理制度改革的活力来源。美国草地管理制度发展的曲折反复,也说明了生态管理政策的失效和调整,禁牧和监管强度的张弛反复,不同利益集团的矛盾诉求和博弈消长,都是草地治理中的正常情况。我国草地治理也可能经历复杂曲折的过程。在下一阶段,草地产权的优化、行政管理的精细化、牧民利益和生态保育目标的协调,是实现我国草地可持续治理的核心要务。     

经济政策不确定性对中国粮食安全的影响

为探究经济政策不确定性对中国粮食安全的影响,基于2000-2018年中国31个省(市、自治区,统计数据未含港澳台地区)的面板数据,采用PVAR模型,研究经济政策不确定性对中国粮食供给安全、获取安全、稳定性安全和资源安全的影响及区域差异.结果表明:1)总体上,经济政策不确定性对中国粮食安全具有负向影响.2)分区域看,粮食...     

中国粮食生产政策体系现状及完善建议

粮食安全是关系国计民生的重要问题,历来受到中国政府的重视。为了从根本上保障粮食供给,夯实国家粮食安全的基础,中国制定了一系列确保和促进粮食生产政策。深入分析了目前中国包括粮食补贴政策、粮食价格政策、产粮大县奖励政策、农业保险政策、土地政策和税费改革等在内的粮食生产政策体系及其实施效果,并通过与发达国家粮食生产政策体系对比研究,提出完善中国粮食生产政策体系的建议:完善粮食补贴政策、改进粮食最低收购价及粮食存储政策、建立健全政策性农业保险制度、强化粮食产销区的利益协调和优化粮食市场调控机制。     

我国粮食最低收购价政策的效应和问题及完善建议

本文阐述了我国粮食最低收购价政策实施9年来,对稳定市场粮价、促进农民增收、保障粮食安全等方面发挥的重要作用。分析了在政策设计方面存在的缺陷,如责任主体与粮食收购主体分离,最低收购价形成机制未明确,收购贷款与利息补贴等没有明确或细化等相关问题;以及在操作方面存在诸如粮食品种差价不合理,执行主体和委托收购库点关系不顺,收购点库不足等问题,制约了政策效果的进一步发挥。从优化政策设计、提高执行效果、完善配套措施三个方面,对粮食最低收购价政策提出完善建议。     

关注林权:中国集体林政策研究国际研讨会综述

公共资源面对的挑战、风险与机遇受到国际社会的关注。文章以“国际公共资源研究协会第十届大会”为背景,对中国集体林研究课题的成果、相关国际会议内容及专家发言作了介绍。研究成果主要形成8个专题报告,国际会议分“中国集体林政策和法律框架的总体回顾”和“中国集体林与生态保护、公司 社区模式”两个部分展开,并形成了5点结论。     

农村土地产权非私有化改革

文章从产权的不同属性来论证中国“新土改”的农村土地产权公有(共有)性不变。通过对“新土改”政策下农村土地产权治理与制定农村土地产权制度一般原则探索,论证“新土改”政策是科学发展观一部分,是新时期具体的马克思主义中国化。     

公共消费的理论创新与政策选择

公共消费包括政府自身消费和社会性消费,以公共风险为逻辑基础,并兼具经济和社会双重属性,既有利于维护经济稳定平衡,是可持续发展的基础;又有利于促进社会公平正义,是国民素质和社会文明程度提高的保障。目前理论界对公共消费问题的探讨大多基于经济视角,基于经济与社会双重视角审视公共消费理论,应树立“消费者主权”意识,明确我国公共消费政策方向。