Adverse Shocks in Agriculture: The Assessment and Management of Downside Risk

This paper investigates the assessment and effects of adverse shocks on agricultural production, with an application to corn yield. Adverse shocks are assessed by the probability of facing low yields, i.e. by the probability of being exposed to downside risk. Defined in terms of willingness‐to‐pay to eliminate risk, the ex‐ante cost of facing adverse events is evaluated under prospect theory. Prospect theory is relevant in the evaluation of adverse shocks as it identifies a role for both loss aversion and oversensitivity to low probability events. The analysis is applied to experimental data on corn yield in the US Corn Belt. Estimates show how the distribution of corn yield is affected by management and technology. Implications for the cost of adverse shocks are examined. The results show how management and technology can reduce exposure to adverse shocks and lower the cost of risk in agriculture.     

An Empirical Analysis of Acreage Effects of Participation in the Federal Crop Insurance Program

The extent to which crop insurance programs have resulted in additional land being brought into production has been a topic of considerable debate. We consider multiequation structural models of acreage response, insurance participation, CRP enrollment, and input usage. Our analysis focuses on corn and soybean production in the Corn Belt and wheat and barley production in the Upper Great Plains. Our results confirm that increased participation in insurance programs provokes statistically significant acreage responses in some cases, though the response is very modest in every case. In the most extreme cases, 30% decreases in premiums as a result of increased subsidies provoke acreage increases ranging from 0.2% to 1.1%. A number of policy simulations involving increases in premium subsidies are considered.     

Urban Influence on Costs of Production in the Corn Belt

This article determines the relative technical efficiency of rural- and urban-influenced crop/livestock enterprises in the Corn Belt. Farmers in urban-influenced locations are less technically efficient than farmers in rural locations. During 1998–2000, stochastic production frontier procedures indicate that a 10% increase in urban influence leads to a close to 4% decrease in technical efficiency. The most successful urban-influenced farms have controlled costs as effectively as rural farms. They have tended to de-emphasize that nondairy livestock activities—particularly beef and hogs—do not rely extensively on off-farm income, and have relatively large, less residential/lifestyle operations compared to less successful urban-influenced farmers. However, our statistical analysis clearly bears out the refrain in popular literature that urban proximity raises the cost for, and decreases the viability of, traditional farms.     

Managing phosphorous soil dynamics over space and time

Understanding the relationship between soil fertility dynamics and crop response is conceptually appealing. Even more appealing is comprehension of the spatial and temporal heterogeneity of these connections over a production surface and across seasons. But gaining knowledge about these interactions is difficult because nutrient carryover dynamics and crop response to inputs are determined simultaneously on the one hand, and sequentially on the other. A second problem enters when crops are rotated, for example, the corn [Zea mays (L.) Merr.]–soybean [Glycine max (L.) Merr.] system commonly practiced in the U.S. Corn Belt. This article examines nutrient carryover–crop response dynamics using data from a corn‐soybean, variable rate nitrogen (N), and phosphorous (P) experiment conducted over five years in Minnesota, USA. Site‐specific corn response to N and P and soybean response to P is estimated with a P carryover equation. Estimates are used in a dynamic programming model to determine site‐specific optimal N and P fertilizer policies, soil P evolution, and profitability. The net present value of managing N and P site‐specifically is compared to a strategy in which these inputs are managed uniformly following Extension guidelines. The results suggest that when P carryover is accounted for in determining optimal P fertilizer rates, returns to the variable rate strategies are higher than returns to a uniform or whole‐field management strategy.     

NITROGEN,PHOSPHORUS AND LAND DEMANDS AT THE US REGIONAL LEVEL: A PRIMAL APPROACH

A primal approach for estimating nitrogen, phosphorus and land demands at the regional level is developed based on the first-order conditions for expected profit maximisation. The approach is applied to State-level data on corn production in the US Corn Belt. The empirical results suggest that technologies in corn production differ significantly across the region, and, consistent with earlier studies in Ireland, fertiliser demands have become less responsive to own-price changes over time. These results are consistent with structural and technological changes that have occurred in agriculture.     

FAIR Act Implications for Land Values in the Corn Belt

In 1996 the federal government enacted the Federal Agriculture Improvement and Reform (FAIR) Act, which represented a sweeping change in public policy toward agriculture. This paper examines the impact of the FAIR legislation on farmland values across the U.S. Corn Belt. A representative farm framework is used to determine the impact of FAIR on farmland values. The analysis suggests that marginal production environments are likely to suffer most severely under FAIR, and that a prolonged period of weak commodity prices could engender sharp declines in farmland values.     

PREMIUM RATEMAKING IN AN ALL RISK CROP INSURANCE PROGRAM1

Fluctuation in farm incomes resulting from variation in crop yield is one of the most significant features in agriculture. Crop insurance is a feasible method by which the farmer can protect his income and his investment from the disastrous effects of crop losses due to natural hazards. This study has attempted to cover two parts. First, it has examined the most important-factors influencing crop yields in connection with the premium rate scheme (i.e. the long-run average yield and the level of coverage). These factors include resource inputs, technology, weather, and stochastic variable. Second, it has developed a refined method of approximating the premium rate. The data used in testing normality were based on the Manitoba Crop Insurance Corporation's annual yield survey covering the years 1916 to 1964. The test shows that none of the annual yield distributions within the area surveyed was normally distributed, revealing that a cartful and exact delineation of a crop risk area is necessary. The findings also show that the cyclical pattern of weather and the upward trend in crop production due to technology were evidently important for the adjustment of the level of coverage and premium rate over time. Additional research relating the effects of weather and technology on crop yields would help to establish a more realistic insurance program. Other aspects should not be overlooked. These include (a) other possible levels besides the existing level of coverage and (b) a livestock or a combined crop-livestock insurance program along with the crop insurance program. The purpose of these additional aspects is to provide farmers with a fuller measure of protection.     

An Evaluation of the Actuarial structure of manitoba crop Insurance Program and its Implications

Very little research has been done in evaluating the basic principles and assumptions of the actuarial structure for premium ratemaking in crop insurance programs. Therefore, the objectives of this study are: (a) to examine the Pearson probability distribution of actual crop yields as compared with an application of normal-curve theory to crop yields as compared with an application of normal-curve theory to crop yield distributions and in turn to crop insurance ratemaking which was suggested by Botts and Boles in 1958 [1]; (b) to evaluate the pure premium rates derived from estimated Pearson probability distributions for wheat yields in 14 crop districts of the province of Manitoba; and to establish an experience rating system for the crop insurance program based upon the estimated Pearson distribution of actual crop yields on the individual farm.     

基于参数和非参数方法的玉米生产效率研究——以吉林省为例

本文以中国玉米主产区吉林省为例,基于非参数HMB指数方法和参数K-L随机前沿生产函数方法,采用1991-2005年投入产出的面板数据(Panel Data),对玉米生产的全要素生产率进行实证分析.结果表明,主产区的玉米全要素生产率(TFP)变动具有周期性的变化特点,每一周期技术进步、技术效率、规模效率和混合效率对玉米全要素生产率变动的作用不同;分区综合结果显示,黄金边缘区玉米生产率的增长幅度最高,黄金玉米主产区玉米生产率的增长幅度次之,非主产区玉米生产率的增长幅度最低.今后为促进主产区玉米全要素生产率增长应采取促进技术进步、挖掘主产区潜力等措施.     

Trends in Agricultural Incomes: An Analysis at the Select Crop and State Levels in India

India's agricultural sector is at a crossroads, facing challenges of stagnation in crop yields, non‐remunerative prices, falling crop incomes and tardy responses from public service systems. There are reports of peasant suicides due to non‐profitability of farming. However, scant empirical evidence is available on changes in real income and wages in the Indian agricultural sector. The present study uses data from the National Accounts Statistics and Cost of Cultivation Surveys to analyse the changes in real income and discusses the underlying reasons. The study reveals that the purchasing power of farmers has remained low and has worsened over recent years. The value of crop output has increased, but a disproportionate rise in input costs has resulted in a fall in crop incomes in several states, with the agriculturally developed Punjab being an exception. Interestingly, real wage rates for agricultural labour have shown an increasing trend, indicating improvement in the welfare of labour.     

Producer Experience, Learning by Doing, and Yield Performance

Current crop insurance rating procedures consider only performance for the individual crop in question. Recent farm legislation has given producers considerable planting flexibility and, as a result, many have shifted to new crops. Producers without a production history for the new crop may be offered levels of insurance that do not accurately reflect their expected yields. Likewise, premium rates may not reflect a producer's actual risk for a new crop. We examine the extent to which information about expected yields may be gleaned from a consideration of historical performance on other crops. We also consider the extent to which yield performance exhibits learning by doing such that yields improve with experience. Though the results are mixed, we generally find that yield performance tends to improve with experience. However, when yields are conditioned on historical yield performance for other crops, the importance of experience is diminished significantly. Yield performance is related to a number of farm characteristics. Finally, we examine the extent to which yield variability is correlated across crops for individual farmers. Implications for crop insurance rating practices are discussed. The results demonstrate robust correlation between a farm's historical yield on other crops and a newly produced crop—a factor largely ignored in current crop insurance contracts.     

协同视阈下淮河生态经济带绿色高质量发展及其空间特征研究

基于淮河生态经济带28座设区市的面板数据,在协同视域下利用容量耦合协调模型从经济、社会、生态3个层面对淮河生态经济带绿色高质量发展水平进行测度,并利用莫兰指数揭示其绿色高质量发展的空间特征。研究表明:淮河生态经济带各区域绿色高质量发展水平及其经济、社会、生态三大子系统的发展水平均呈明显的上升趋势;从区域平衡性看,淮河生态经济带内部三大区域绿色高质量发展水平差异显著,呈东部海江河联动区、北部淮海经济区、中西部内陆崛起区递减态势;从发展充分性看,各地区经济子系统和社会子系统的发展情况呈现时空一致性,但其与生态子系统的发展情况具有显著差异;从空间集聚特征看,淮河生态经济带绿色高质量发展水平及其社会子系统空间集聚不显著,而经济子系统和生态子系统则呈现明显的正向自相关特征。基于此,提出相关对策建议,以期推进淮河生态经济带绿色高质量发展。     

Regional Impacts of a U.S. Hog Slaughter Plant Closing: The Thorn Apple Valley Case

As the 1998 U.S. hog market collapse unfolded, Thorn Apple Valley ceased hog slaughter operations at its Detroit, Michigan plant. We examine the impacts on Michigan live hog prices relative to Eastern Corn Belt hog prices. Results indicate that Michigan producers' relative price advantage diminished after the closure as procurement competition changed. As the impacts of the 1998 hog market collapse were absorbed, Michigan producers' relative price advantage became consistently negative. Examination of Michigan's market hog production distribution indicates postclosure shifts away from production in areas geographically near to Thorn Apple Valley and growth in counties geographically closer to alternative packers.     

基于修正引力模型的“一带一路”中国段省区空间经济联系分析

区域经济联系对各区域的经济发展产生着重要的影响,研究“一带一路”中国段省区经济联系强度是国家建设“一带一路”省级宏观经济调控的必要方式。文章从定性和定量的角度,基于修正的引力模型,揭示“一带一路”中国段省区经济联系强度“点-线-面”三维度特征。研究结果表明:(1)省区间中心性指数差异明显,在区域分布上具有明显的梯度性;(2)“一带一路”倡议的提出有效提升了中国段大部分省区的经济实力,中心性指数有明显上升趋势;(3)省区间发展不平衡的现状仍较为突出,两个核心区的带动辐射能力差异大,且核心区的经济辐射带动作用都需要改善与提升。     

Ranking Crop Yield Models Using Out-of-Sample Likelihood Functions

There has been considerable debate regarding which probability distribution best represents crop yields. This study ranks six yield densities based on their out-of-sample forecasting performance. The forecasting ability for each density was ranked according to its likelihood function value when observed at out-of-sample observations. Results show that a semiparametric model offered by Goodwin and Ker best forecasts county average yields.     

Regime shifts and technology diffusion in crop yield growth paths with an application to maize yields in Zimbabwe

An alternative specification for the trend component of crop yield growth is developed and applied to maize yield data for Zimbabwe's large-scale farming sector. This accounts for permanent regime shifts as new technologies are discovered but allows gradual absorption as adoption follows a diffusion path. Econometric methods are used to estimate the timing and importance of innovations, as well as the length of the diffusion path. Results from an application to Zimbabwe commercial maize yields indicate two major regime shifts that can be associated with the introduction of hybrid seed varieties, and a diffusion path that extends over a decade.     

新型城镇化、产业结构升级与水污染关系研究

基于2008—2017年长江经济带9省2市的面板数据,运用脱钩-PVAR两阶段模型对新型城镇化、产业结构升级与水污染关系的演变趋势和影响机制进行分析。研究发现:水污染与新型城镇化、产业结构升级的关系皆呈现扩张负脱钩—强脱钩的演变趋势,说明长江经济带城镇化与工业化经历了先污染后治理的阶段,但最终实现了经济发展与水污染状况改善的双重目标。脉冲响应与方差分解的结果表明,现阶段新型城镇化的水污染治理效应并不明显,水污染与产业结构升级之间存在着明显的负向关系,且前者对后者的解释作用较强。分别对长江经济带的上、中、下游进行方差分解,发现各变量间的相互影响程度存在明显的区域差异,制定水污染防治政策时不可一概而论。     

污染排放约束下长江经济带农业绿色水资源利用效率研究

基于超效率SBM模型和GML指数对2011—2019年长江经济带农业绿色水资源利用效率进行了时空差异分析及动态演变趋势分析,并在此基础上运用Tobit回归模型实证检验了农业绿色水资源利用效率的影响因素。研究结果表明:2011—2019年长江经济带农业绿色水资源利用效率整体时序变化平稳,但内部空间差异显著;多数地区的技术效率水平未跟上行业技术变革的步伐;政府管控水平、农田水利建设水平等对农业绿色水资源利用水平呈显著正向影响。指出长江经济带各地区应通过创新农业用水方式、挖掘节水减排潜力等方式来改善其农业水资源利用现状。     

Cropland expansion and grassland loss in the eastern Dakotas: New insights from a farm-level survey

The western Corn Belt region of the United States has become a hotspot for agricultural extensification and consequent land use and land cover changes. The goals of this research were to characterize geographic patterns of grassland loss resulting from cropland expansion in the eastern Dakotas, and to understand how these changes were associated with characteristics of individual farms and farm operators. We collected data on grassland conversion and other land use decisions through a mail survey of farm operators in North and South Dakota. Overall, 40% of respondents converted at least some grassland to cropland between 2004 and 2014, and the total acreage of converted grassland was equivalent to 5.1% of the surveyed farm acreage. Although most converted grassland acres (3.2% of farm acreage) were from land enrolled in the conservation reserve program (CRP), there were also substantial amounts of native grassland conversion (1.0%) and tame grassland conversion (0.9%). The total acreage of grassland conversion was more than four times larger than the acreage enrolled in CRP and other conservation programs. Different types of grassland conversion (e.g., native grassland versus CRP) were concentrated in different parts of the study region, and were spatially disjunct from the areas of highest conservation program enrollment. Larger farms were more likely than smaller farms to expand their cropland acreage and accounted for a disproportionate share of grassland conversion. Younger farm operators, higher levels of farm income, higher proportions of rented croplands, and marginal yields were also associated with cropland expansion and grassland conversion. Although CRP and other land retirement programs will remain important policy mechanisms for conservation in this region, they are not sufficient to maintain current levels of grassland cover and do not provide protection for native grasslands. Alternative conservation strategies and new agricultural policies are thus critically needed to maintain the ecosystem services provided by grasslands.     

长江经济带水足迹与经济高质量发展的脱钩效应

基于2009—2018年长江经济带11个省市水足迹的面板数据,运用Tapio脱钩弹性系数模型研究水足迹与经济高质量发展之间的脱钩效应,利用STIRPAT模型研究水足迹强度的驱动因素。研究结果表明:长江经济带水足迹总量在2016年出现拐点后逐年下降,而经济高质量发展水平整体处于稳步上升状态,二者整体上呈现弱脱钩趋势。其中,长江下游省市基本实现强脱钩,中上游省市从弱相关性向强相关转变。