沈阳城市周边耕地多功能评价

[目的]为探索城市化影响下城市周边耕地多功能的现状,分析其空间差异,为耕地保护及城市周边耕地发展提供参考。[方法]从耕地的生产、生态、社会和景观4个功能出发构建评价指标体系,利用熵权法确定指标权重,加权求和法计算单一功能和多功能值,并用ArcGIS进行空间分析,对沈阳城市周边50个乡镇(街道)的耕地多功能性进行综合评价。[结果](1)沈阳城市周边耕地的多功能性空间差异较为明显。生产功能远郊平原区最强,远郊山区和近郊区较弱;生态功能总体偏弱,个别乡镇较好;距离城市越远,社会功能越强;景观功能近郊区较强,远郊区较弱。(2)耕地的生态、社会和景观功能主要受距市中心距离的影响,生产功能受地形和距市中心距离的双重影响,而多功能则受地形、距市中心距离及各乡镇(街道)耕地主导功能等的综合影响。(3)沈阳城市周边的大多数耕地以农业生产为主导,景观文化功能整体相对较弱。近郊区耕地生态功能所占比重较大,但社会功能比重较小,远郊区则与之相反。[结论]沈阳城市周边耕地多功能性空间差异较为明显且不均衡,应科学规划城市周边耕地功能,优化空间布局,协调耕地各功能的关系,促进耕地多功能综合发展。     

Computing the Gerber–Shiu function by frame duality projection

Inspired by some works of Kirkby, J. L. [2015. Efficient option pricing by frame duality with the fast Fourier transform. SIAM Journal on Financial Mathematics 6(1), 713–747; 2016. An efficient transform method for Asian option pricing. SIAM Journal on Financial Mathematics 7(1), 845–892], we present a systematic study on effectively computing the Gerber–Shiu function in the Lévy risk model, where the frame duality projection is used for approximation. By introducing an auxiliary function, we provide a smooth extension of the Gerber–Shiu function, which has closed-form Fourier transform and is differentiable over the whole real line under some conditions. The objective function is approximated by its frame duality projection onto a Riesz basis, and the projection coefficients are readily computed by the fast Fourier transform algorithm. Error analysis is made and the effectiveness of our results will be further illustrated in the numerical experiments.     

时空大数据支持的土地储备智能决策体系与应用研究

研究目的:设计土地储备智能决策体系,将土地储备决策环节进行科学化、定量化和模型化,为政府合理开展土地储备提供决策依据。研究方法:遵循科学性、实用性、先进性、开放性原则,以数据为驱动,人工智能为核心,通过基于Hadoop/Spark的大数据处理技术、多源异构数据融合技术、智能决策模型集对多源时空大数据挖掘分析。研究结果:提出了土地储备智能决策体系,研究了一套面向土地储备的决策方法集,实现对现状条件的精准刻画,对土地储备规模、结构、时序等内容的科学决策;在此基础上,研发了智能决策支持平台,将数据资源共享、现状条件评估、智能决策专题等功能集成,构建土地储备智能决策"一张图",并实现平台的自我学习和更新。研究结论:应用于宁波市实例验证,该体系有效地促进了土地储备科学智慧决策,对优化土地资源配置具有参考意义。     

关于推进南疆农业结构调整的思考

[目的]新时期,加快推进南疆农业产业结构调整,促进农牧民全面实现脱贫致富奔小康,实现农业可持续发展,是推进南疆经济社会发展的重要手段。通过分析南疆地区水土资源条件和农业产业结构,提出推动南疆农业结构调整的发展方向和重点领域,并提出相应的政策建议。[方法]文章系统梳理南疆农业结构调整相关文献的基础上,通过实地调研和调阅南疆地区农业部门相关资料,全面分析南疆水资源利用、农牧业生产、农产品加工等方面面临的问题,提出针对性措施。[结果]南疆水资源处于过度开发状态,通过压减种植面积或调整种植结构节水空间十分有限,饲草料短缺矛盾较为突出,种养不平衡凸显,农产品加工业滞后,产业结构不合理。[结论]推进南疆农业结构调整,重点是加强水利工程建设提高骨干输水工程防渗率,发展高效节水农业,强化草畜配套平衡,大力发展农产品精深加工,推进农业产业化发展。     

Assessing cost‐effectiveness when environmental benefits are bundled: agricultural water management in Great Barrier Reef catchments

Using economic analysis to prioritise improvements in environmental conditions is particularly difficult when multiple benefits are involved. This includes ‘bundling’ issues in agricultural pollution management, where a change in management action or farming systems generates multiple improvements, such as reductions in more than one pollutant. In this study, we conceptualise and compare two different approaches to analysing cost‐effectiveness when varying bundles of benefits are generated for a single project investment. Each approach requires data to be transformed in some way to allow the analysis to proceed. The index approach requires the transformation on the benefits side so that the effects of multiple pollutant changes can be combined into a measure for each project which can then be compared to costs. By comparison, the disaggregation approach requires the transformation on the costs side where costs for each project have to be apportioned across the different pollutants involved. The paper provides novel insights with an application to agricultural water quality improvements into the Great Barrier Reef in Australia, demonstrating that while both approaches are effective in prioritising projects by cost‐effectiveness, the disaggregation approach provides more insightful results and values that may be relevant for use as upper value guidelines in future project selection.     

The impact of climate change on labour demand in the plantation sector: the case of tea production in Sri Lanka

Limited opportunities for crop switching and lengthy preharvesting periods make the plantation sector particularly vulnerable to climate change. Surprisingly, however, the economic consequences of climate change on plantation crops are seldom analysed. Drawing on a unique primary panel data set from a representative cross section of 35 tea estates in Sri Lanka over the period 2002–2014, this study implements a structural model of estate profit maximisation to estimate the elasticity of labour demand with respect to different components of weather. Results indicate a negative relationship between labour demand and rainfall in the south‐west monsoon, the north‐east monsoon and the second inter‐monsoon. A positive relationship is found between labour demand and rainfall in the first inter‐monsoon. Overall, predicted changes in rainfall by 2050 are anticipated to reduce labour demand by approximately 1,175,000 person‐days per year across Sri Lanka's tea plantation sector. This is likely to have considerable social and welfare implications, particularly for the Indian Tamil women who comprise the majority of the sector's workforce.     

Sustainability of the fiscal imbalance and public debt under fiscal policy asymmetries in Sri Lanka

This paper investigates the sustainability of Sri Lanka’s fiscal imbalance and public debt. To test for sustainability of the fiscal imbalance, the study applies a symmetric ARDL (autoregressive distributive lag) technique to estimate a government intertemporal budget constraint. And to test for sustainability of public debt, it applies an asymmetric ARDL technique to estimate a fiscal reaction function, which allows for differential responses in the primary budget balance depending on whether shocks to regressors are positive or negative. Annual data for the period 1961–2018 are used in the estimations. The results indicate that Sri Lanka’s fiscal management is inconsistent with strong form sustainability, which requires that expenditures not grow faster than revenues. However, estimation of the fiscal reaction function finds robust evidence for fiscal policy asymmetries. Evidence emerges that Sri Lanka’s fiscal policy stance is procyclical with strong stabilization tendencies in economic expansions that are not sustained in contractions. Against upsurges in the debt-to-GDP ratio, authorities are found to pursue fiscal consolidation, thus suggesting weak form sustainability.     

基于双重约束的区域耕地整理适宜性评价研究

[目的]科学合理的适宜性评价是确保耕地整理能够有效开展的前提条件,同时对于我国的耕地保护与粮食安全保障也具有极为重要的意义。[方法]该研究首先选取可以反映区域耕地整理适宜性的指标因子,然后参考胡学东提出的约束条件评价模型,引入区域生态安全和社会经济双重约束,对研究区域在双重约束下的耕地整理适宜性进行评价,并通过K-Means聚类法将研究区域的耕地整理适宜性分区进行合理划分。[结果]生态安全约束和社会经济约束对区域耕地整理适宜性水平具有重大影响,高生态安全约束与高社会经济约束会降低耕地整理的适宜性,低生态安全约束与低社会经济约束会提高耕地整理的适宜性。[结论]引入生态安全约束和社会经济约束后,可以在一定程度上反映山地区域在社会经济与生态安全双重约束状态下的耕地整理适宜性情况,耕地整理适宜性评价结果更加符合当地实际情况,约束条件评价模型可以更加合理准确地对处于约束条件下的耕地整理适宜性进行评价,是对耕地整理适宜性评价方法的丰富与完善。     

长江经济带中三角地区农业结构的分析与优化对策

[目的]从宏观、中观和微观3个层面深入分析长江经济带中三角地区湖北、湖南和江西3省的农业产业结构及其各产业差异性和相对优势及其竞争力。[方法]在宏观层面运用了传统的基尼系数分析3个省份历史发展上的地区经济水平差异,判断3个地区经济发展是否存在虹吸效应;从中观层面运用区位熵指数分析法分析区域农业产业结构,从农畜林渔等方面判断各区域产业专业化水平程度;从微观层面运用偏离—份额分析法(SSM)分离出3个地区的各部门产业的优势及其竞争力。[结果]区域内的经济差异变化呈不断增大的趋势,基尼系数不断扩大;湖北的种植业、渔业和农林牧渔服务业,湖南的种植业、林业、畜牧业和农林牧渔服务业,江西的林业、渔业都较中三角地区对应的子产业的区位熵指数高;江西木材和竹加工业和烟草业具有较大的产业竞争优势,湖北的茶叶、水产和瓜果疏菜产业优势明显,湖南地区农业产业综合优势主要在于烟草、水果、肉类以及木材和竹类加工业。[结论]通过比较地区农业产业竞争优势,提出发展地区产业特色,合理布局全域农业产业,提高农产品附加收益,稳固对结构优化的资金支持等对策建议。     

中国海外耕地投资的区位特征及其影响因素*——基于2000—2016年土地矩阵网络数据

［目的］分析中国海外耕地投资的区位特征及其影响因素，以促进我国海外耕地投资的合理布局，提高农业投资效率。［方法］以2000—2016年中国137宗海外耕地投资项目及其所涉及的35个东道国作为研究样本，运用Spearman相关分析方法，分别以耕地投资面积和耕地投资项目数量作因变量，研究其与各影响因素的相关关系，并用对应分析法进一步探究各东道国的相对优势。［结果］（1）我国海外耕地投资区域集中在东南亚且由周边国家向外扩展，被投资耕地用途多样，投资规模自2004年开始急剧上升，近年来呈下降趋势。（2）我国海外耕地投资以效率寻求型和市场寻求型为主，倾向于资源丰富、与我国距离较近、制度相似、经济关系良好但发展水平不高的国家。（3）根据各地区的比较优势，亚洲国家适合效率寻求型和市场寻求型的企业投资，欧洲和美洲国家适合资源寻求型和战略资产寻求型的企业投资，非洲国家适合资源寻求型、效率寻求型和市场寻求型的企业投资。［结论］中国农业企业应结合企业投资目标和各地区的比较优势，合理选择投资区位，适时转变投资策略与模式，积极防范海外耕地投资过程中的自然风险、政治环境风险和道德风险等，以提高投资效果。