中国农业科技进步贡献率结构演变及提升路径

本文从要素体现式技术进步理论视角强化农业科技进步贡献率测算的理论基础，针对农业科技进步贡献率测算存在的问题，对测算模型和估计方法进行优化调整，进一步将农业技术进步细化分解为中性技术进步、要素增强技术进步等部分，以此来解析中国农业科技进步贡献率结构特征及演变规律。结果显示，1990—2020年中国农业技术进步速度为2.44%,其中中性技术进步速度呈快速上升趋势，并已成为驱动中国农业科技进步的主导力量，物质增强技术进步呈现明显下降趋势，劳动增强技术进步保持平稳上升态势；当前中性、物质、劳动技术进步在农业技术进步中的比重分别为50.7%、32.3%和17.3%,其技术进步贡献率分别为31.3%、23.1%和10.4%;2000—2020,中国农业科技进步贡献率从35%快速上升至超过60%水平，表明我国农业科技工作取得显著成效，农业发展方式已逐步实现由早期的要素依赖型向科技驱动型转变。最后，从加快科技创新步伐、重构农业科技推广体系、加大农业支持保护力度等方面，提出促进中国农业科技进步贡献率水平提升的实现路径。     

论“八五”期间我国渔业科技进步的贡献率

这是一篇研究“八五”期间我国渔业科技进步经济评价的综合报告。在阐述评价理论与测算方法的基础上，提出了“八五”期间我国渔业科技进步对渔业总产值增长速度的贡献率为46％、物质费用贡献率为44％、劳动力贡献率为6％，养殖面积贡献率为4％。     

1990—2007年北京市农业科技进步贡献率的测算

本文运用Cobb-Douglas生产函数建立农业科技进步贡献率测算模型,对北京市1990—2007年农业科技进步贡献率进行测算,结果表明:北京市农业科技进步率由1990—1998年的57.09%上升到1999—2007年的78.32%。在以上两阶段,农业总产值增长率由5.62%增长到8.23%,物质消耗的增长率由9.97%增长到11.02%。本文基于对以上农业各投入要素对于北京农业总产值增长的影响状况,提出了促进都市型现代农业发展的政策建议。     

科技进步对广东农业发展作用的实证研究

根据改进后具有广泛适应性的C—D生产函数模型，对广东省1986—2005年农业科技进步贡献率进行了测算和分析。结果表明，20年来农业科技进步对广东农业的贡献份额为32．92％，“十五”期间达到了53．22％。广东农业经济增长方式正由过渡型农业经济增长向集约型农业经济增长方式转变。     

黑龙江垦区“九五”科技进步作用分析

为了加强科技进步对率先实现农业现代化的推动作用,我们对黑龙江垦区“九五”期间科技进步贡献率进行了测算,感到垦区在以科技为先导,加速实现现代化上已经迈出了坚实的步伐。垦区科技进步贡献率“九五”与“八五”相比总水平提高了４个百分点。我们分别对垦区的总体、大农业、种植业、畜牧业、工业的科技进步贡献率进行了测算,结果是：总体为６０％,大农业为６２％,种植业为６６％,畜牧业为４１％,工业为５４％,与“八五”期间相比提高或降低的百分比分别为４％、－１％、１％、－１１％、１０％。１．测算对象及模型的选择我们对…     

辽宁省2008-2012年农业科技进步贡献率的测定与分析

本文以辽宁省统计局发布的2008-2012年度统计数据为基础,应用增长速度方程法测算辽宁省农业科技进步贡献率。研究中选取农林牧渔总产值、农林牧渔业中间消耗和农林牧渔劳动力等数据指标,换算可比价格进行数据处理运算,计算得出辽宁省2008-2012年农业科技进步贡献率为56.2%。辽宁省农业科技贡献份额的测算结果显示,辽宁省仍处于传统农业向现代农业过渡阶段,但科技进步对农业增长的贡献作用将越来越大。     

农业科技进步贡献率的“偏倚”分析

本文作者从农业科技进步贡献率计量模型入手,分析了计量中的“模型偏倚”和“统计偏倚”,提出了其测算准确性的异议     

数说

正我国农业科技进步贡献率达56%科技部近日举行新闻发布会,介绍了"十二五"期间我国农业农村科技发展情况。科技部副部长徐南平表示,我国农业科技进步贡献率由2010年的52%提高到2015年的56%以上,林业科技进步贡献率由43%提高到48%,基本保持在每年近一个百分点的增长速     

甘肃14市州“十二五”农业科技进步水平综合评价

[目的]市州农业科技进步是国家农业科技发展的基础,从微观层面测算农业科技进步贡献率,比较分析市州间农业科技进步水平及形成差异的原因,不仅可为各市州客观认识本地区农业科技发展水平提供依据,而且对明确未来发展现代农业的工作重点提供决策参考。[方法]文章运用增长速率方程法(Solow余值法),对"十二五"时期甘肃14市州农业科技进步贡献率进行测算,并进行聚类分析。[结果]农业科技进步贡献率在各市州间差异显著,呈明显的不均衡性。"低投入、低消耗、科技进步贡献率高"型2个市、"适度投入、适度消耗、科技进步贡献率较高"型5个市、"高投入、高消耗、科技进步贡献率有限"型5个市、"投入有限、消耗有限、科技进步贡献率低"2个市,表明提高市州农业科技贡献率、推动农业经济发展的潜力巨大。[结论]增强区域农业科技创新能力,提高农业科技成果推广及应用效益,提高农业从业人员的科技意识及水平,以及发展市州特色产业、壮大区域经济实力是甘肃省市州未来促进农业科技进步的重点方向。     

农业技术进步对农业经济增长贡献的定量研究

论述了农业技术进步的涵义及其对经济增长贡献率测定的经济原理，评析了四种常用的农业技术进步贡献率的测定方法。并依据农业边界生产函数测算了我国“七五”期间农业技术进步对农业经济增长的贡献率大约在３２－３３％之间。     

USGS"2000世界油气评价"待发现油气资源预测法

美国地质调查局 2 0 0 0年的油气资源评价中 ,主要进行了两个方面的预测 :待发现油气资源预测和储量增长预测。待发现油气资源的预测主要运用了油气藏规模分布预测方法及蒙特卡洛模拟方法。     

20世纪中期关中地区的土地问题 --以高陵县通远乡为例

本文通过对土地改革前后高陵县通远乡的土地状况的个案分析，论证了正是因为关中地区人地关系的宽松，租佃关系不普遍，地主和富农拥有的土地不多，结果在土地改革期间，关中地区可供分配的土地比较少，当地政府无法同时做到既完全贯彻中央精神，又充分考虑到地方实际情况，最终在实际执行中，导致了中央政令与地方具体实践在一定程度上的背离；而就产中地区的土地改革本身而言，其效果是不经济的。     

分析后感性1999-2009

前言后感性是在85新潮、89大展之后,中国社会情绪正处在一个失落的底点,85-89的艺术家大部分流落海外,与之前的70年代末星星画会情况相仿佛。而中国当代艺术的发展也正处在一个从强调自我身份(身份认同)、民族观(世界观的一部分)、颠覆与革命(89事件)、全球化(与世界接轨)等等现象迸发的转     

林业资源型城市经济转型新思路

针对资源型城市伊春市的具体情况，从产业、运作方式、创新机制和观念，合理安排劳动力就业等方面，提出了实施资源型城市转型的新思路和新措施。     

可持续发展的实质——建设资源节约型社会

我国正面临着日益严峻的资源紧缺形势.严峻资源形势呼唤资源节约型社会;可持续发展实质就是建设资源节约型社会;资源的稀缺性要求建设资源节约型社会.建设资源节约型社会是我国经济社会可持续发展的必由之路和唯一出路,势在必行.     

关于建设高素质农村基层干部队伍的思考

本文以广东省梅州市第四届村委会组成人员的文化程度和年龄结构为基本数据，对当前农村基层干部队伍现状、存在问题及原因进行分析，并提出建设高素质农村基层干部队伍的几点建议。     

森林生态效益补偿的理论探因和资金筹措浅析

阐述外部影响的概念、类型、影响,分析外部影响与市场失灵的关系及其解决办法。用经济学理论分析森林生态效益具有外部经济的原因,提出了解决森林生态效益外部经济问题的办法是进行森林生态效益补偿,并分析了其中的原因。对森林生态效益补偿资金筹措的原则和途径进行了分析,认为资金募集的途径必须具有公开性、公众性,提出了五种主要的资金筹措方式和建议。     

Editorial - Multiple-use forestry

The problem of multiple-use forestry arises because (1) a forest can be managed to provide a wide range of products and services, (2) the different uses are not perfectly compatible with each other, and (3) some products are not priced in markets and many of the services a forest provides have the characteristics of public goods. Examples of major forest products include, in addition to timber, edible berries, fungi, and hunting games. Forests also provide recreation opportunities and various environmental services (such as regulating local climate, reducing soil erosion, reducing pollutants in the atmosphere, regulating the global climate, providing habitats for wildlife, etc.). The outputs of nontimber goods in general depend on the quantity and structure of the forest, which can be changed by various forest management activities. However, a forest state most suitable for the production of one good is usually not optimal with respect to another good. Typically, there does not exist a set of management activities that simultaneously maximize the outputs of timber and all other goods.Another way to understand the conflicts between different uses is to view standing timber as an intermediate product of forestry investment, which is employed as an “input” for the production of timber products and nontimber goods. Thinking in this way, the conflicts arise partly because timber production and nontimber uses compete for the same input, and partly because of the differences in the “production technology” among different nontimber goods. A change in the standing timber may have positive impacts on some nontimber uses, but have negative effects on others. Because of the conflicts among different uses, it requires that both timber products and nontimber goods should be explicitly incorporated into forestry decision-making in order to achieve the greatest benefits to the forest owner and/or the public.Most of the economic analyses of multiple-use forestry decisions have explicitly or implicitly adopted the view that multiple-use should be achieved in individual stands. Each stand should be managed to produce an optimal mix of timber products and nontimber goods. Another view of multiple-use forestry is to manage each stand for a primary use, whereas multiple-use concerns are addressed by allocating different stands in a forest to different uses. A general argument in support of the primary-use view is that specialization makes for efficiency. The production of timber and nontimber goods is a joint process, however. Strictly speaking, one cannot separate timber production and the production of different nontimber goods. For example, managing a stand for timber production does not exclude the possibility of producing some nontimber goods in the stand. Since every stand usually produces more than one product, efficient multiple-use forestry requires that each stand should be managed for an optimal mix of timber and nontimber outputs. On the other hand, it may well be the case that the optimal multiple-use mix for a particular stand consists of a maximum output of one product. In this case the optimal multiple-use management decision would coincide with the optimal decision pertaining to a single use. In other words, it may be optimal to manage a particular stand for one primary use. Using the terminology of economics, primary-use may be efficient for stands in which the multiple-use production set is nonconvex. Recent research has explored several sources of nonconvexity in the multiple-use production set. However, there is no evidence supporting the argument that specialization is always more efficient than multiple-use management of individual stands. From an economics viewpoint, efficient primary-use is special cases of multiple-use stand management.A widely recognized limitation of multiple-use stand management is that, by considering each stand separately, one neglects the interdependence of nontimber benefits and ecological interactions among individual stands. The nontimber benefits of a stand depend on the output of nontimber goods from other stands. Likewise, the nontimber output from one stand affects the value of nontimber goods produced in the other stands. Ecological interactions among individual stands imply that the output of nontimber goods from two stands in a forest differs from the sum of the outputs from two isolated stands. These interdependence and interactions imply that the relationship between the nontimber benefits of a stand and the stand age (or standing timber stock) cannot be unambiguously determined - it depends on the flow of nontimber goods produced in the surrounding stands. Therefore, it is improper to determine optimal decisions for the individual stands independently. In stead, efficient multiple-use forestry decision should be analyzed by considering all the stands in a forest simultaneously.Another serious limitation of multiple-use stand management is that each stand is treated as a homogenous management unit to be managed according to a uniform management regime. One implicitly assumes that the boundaries of each stand is exogenously given and will remain unchanged over time. This assumption imposes a restriction on the multiple-use production set, thereby creates inefficiency. As an example, consider a large stand with a nonconvex production set. It may be possible to eliminate nonconvexity in the production set and push the production possibility frontier outwards by dividing the stand into several parts and managing each part for a primary-use. It may also be efficient to combine two adjacent stands into one to be managed following a uniform regime, because of the presences of fixed management costs, and/or because the relationship between some nontimber outputs and stand area is not linear.In contrast to income from timber production, nontimber goods produced at different time points are not perfect substitutes. The rate at which a forest owner is willing to substitute a nontimber good produced at one time point for that produced at another time point changes with the outputs of the nontimber good at the two time points. In general cases, the nontimber goods produced at one time point cannot be consumed at another time point, and the marginal utility of a nontimber good decreases when its output increases. This provides a motivation for reducing the variation in the output of nontimber goods over time. An effective approach to coordinating nontimber outputs over time is to apply different management regimes to different parts of a stand, or apply the same regime to adjacent stands, which would change the boundaries of the stands. Preserving the existing stand boundaries would limit the possibility of evening out the nontimber outputs over time, and thereby lead to intertemporal inefficiency in multiple-use management.In previous studies of multiple-use forestry decisions the nontimber outputs or benefits are usually modeled as functions of stand age or standing timber stock. Future flows of nontimber goods or benefits are incorporated into a stand/forest harvest decision model to explore the implications of nontimber uses for optimal harvest decisions. While stand age and standing timber stock may have significant impacts on nontimber outputs, other forest state variables, e. g. the spatial distribution of stands of different ages/species, may be of great importance to the production of nontimber goods. Recognition of such forest state variables could change the relationship between timber production and nontimber outputs and therefore change the optimal forest management decisions.In summary, multiple-use forestry is not simply an extension of timber management with additional flows of benefits to be considered when evaluating alternative management regimes. Recognition of multiple uses of a forest leads to two fundamental changes of the forestry decision problem. First, the optimal intertemporal consumption of forestry income is no longer separable from forest management decisions. In general, the optimal intertemporal consumption of forestry income depends on future flows of nontimber goods, implying that the consumption-saving decision should be made simultaneously with the decision on the production of timber and nontimber goods over time. Secondly, it is no longer appropriate to optimize the management regime for each stand separately. The nontimber outputs from a forest depend on the age distribution of individual stands, and on a wide range of other forest state variables such as the spatial distribution of stands of different ages and tree-species composition. Ecological interactions and interdependence among stands imply that management regimes for different stands should be optimized simultaneously. In addition to changing rotation ages and harvest levels, efficient multiple-use forestry requires optimizing the spatial allocation of harvests, redefining the boundaries of stands, coordinating the choices of tree species in regeneration of harvested area and so on.The lack of rigorous production functions for nontimber goods imposes a severe restriction on attempts to perform comprehensive economic analyses of multiple-use forestry decisions. This restriction in itself is no justification for ignoring many of the key aspects of multiple-use forestry problem and modeling the problem as one of determining the optimal rotation age or optimal harvest level. It requires that economic models of multiple-use forestry should be developed with special consideration of the vague and imprecise information regarding the relationships between nontimber outputs and forest state variables.Peichen GongDepartment of Forest EconomicsSE-90183 UmeåSweden