Risk Management for Grain Processors and “Copulas”

The importance of calibrating hedging strategies for processors has escalated primarily due to the sharply increased volatility of futures, product, and by‐product prices. The purpose of this paper is to analyze price risk‐management strategies for wheat flour milling using copula distributions. While the application is for flour milling, it has similarities with other processing industries which confront one or more ingredients, one or more outputs, and futures for one of the commodities and/or products. The paper develops utility maximizing models encompassing expected return and risk. Alternative scenarios are evaluated. First, the models were used to derive optimal hedge ratios, as well as various measures of risk and return under alternative scenarios, and hedge durations. The results indicated hedge ratios are typically less than 1. The hedge ratios for the Mean‐value‐at‐risk (M‐VaR)‐Copula model increased with greater durations. Second, the VaR for the M‐VaR‐Copula was in most cases less than the noncopula specifications. Thus, noncopula models may over state risk as represented by VaR.     

Technology Adoption and Pest Control Strategies Among UK Cereal Farmers: Evidence from Parametric and Nonparametric Count Data Models

This paper examines the intensity of technology adoption and integrated pest management strategies employed by UK farmers, using both parametric and nonparametric methods. We employ a unique survey dataset collected from UK cereal farmers to assess the determinants of technology adoption in relation to pest management. Our preferred model specification is nonparametric, with models estimated yielding broadly similar results, with some important qualitative differences. All models indicate that total area farmed is positively related to the number of technologies adopted, whereas the number of years of experience of the farmer is negatively related. We also find evidence with our nonparametric specification of significant statistical differences for number of adoptions by region across the UK.     

Design efficiency for non‐market valuation with choice modelling: how to measure it,what to report and why*

We review the basic principles for the evaluation of design efficiency in discrete choice modelling with a focus on efficiency of WTP estimates from the multinomial logit model. The discussion is developed under the realistic assumption that researchers can plausibly define a prior belief on the range of values for the utility coefficients. D‐, A‐, B‐, S‐ and C‐errors are compared as measures of design performance in applied studies and their rationale is discussed. An empirical example based on the generation and comparison of fifteen separate designs from a common set of assumptions illustrates the relevant considerations to the context of non‐market valuation, with particular emphasis placed on C‐efficiency. Conclusions are drawn for the practice of reporting in non‐market valuation and for future work on design research.     

Modelling the Risks Associated with the Increased Importation of Fresh Produce from Emerging Supply Sources Outside the EU to the UK

The risk of non‐indigenous plant pests entering the UK via international trade in fresh produce is increasing. The objective of this article is to identify existing and emerging supply sources for UK fresh produce importers and examine the extent to which they could provide invasion pathways. We tested the hypothesis that increased imports of fresh produce from new sources outside the European Union could increase the risks of non‐indigenous insect pests. We use a bio‐economic model approach in which the number of species arrivals is a function of the volume of imports, whereas the volume of imports itself is a function of gross domestic product, relative import prices and seasonality. The study has identified clear trends, which show import volumes of fresh produce and species detections increasing from new supply sources. If this trend continues in the future, then the UK inspection agency should expect to confront species from new suppliers in much greater numbers, given that import volumes of fresh produce are income elastic.     

‘Deal’ or ‘No Deal’? Impacts of Alternative Post‐Brexit Trade Agreements on UK Agriculture

Brexit will have important implications for UK agricultural commodity markets due to potentially significant changes to trade flows. We quantify the sectoral impacts on UK agriculture of three illustrative scenarios, which capture a broad range of potential trade arrangements: Bespoke Free Trade Deal , WTO Default and Unilateral Trade Liberalisation . It is estimated that the projected market impacts are relatively small if the UK negotiates a Bespoke Free Trade Agreement with the EU. The projected impacts are much greater under the two other scenarios, which capture potential trade arrangements if ‘no deal’ is reached. The high tariffs imposed under the WTO default scenario lead to significant adjustments in trade between the UK and EU‐27, with the impact on the domestic UK market depending on whether the UK is a net importer or a net exporter of the relevant commodity. All sectors experience price and production declines under the trade liberalisation scenario in which the UK unilaterally sets tariffs on imports from both the EU‐27 and the rest of the world to zero; the impacts are particularly severe in the beef and sheep sectors where international competition is very strong.     

Sectoral gender wage gap in Vietnam

Abstract

Price forecasting systems are of considerable importance to food security management by governments’ and non‐governmental organizations. Sparse data availability in low‐income economies, however, generally necessitates reliance on reduced form forecasting methods. Relatively recent innovations in heteroscedasticity‐consistent time series techniques offer price forecasting tools that are feasible given available data and analysis technologies in low‐income economies. Moreover, extended GARCH models exhibit superior out‐of‐sample forecast accuracy using monthly food price data from Madagascar. These techniques also permit cost reduction in food security operations by more precise estimation of the risk of hitting a critical price level.     

Assessing the Forecasting Performance of a Generic Bio‐Economic Farm Model Calibrated With Two Different PMP Variants

Using linear programming in bio‐economic farm modelling often results in overspecialised model solutions. The positive mathematical programming (PMP) approach guarantees exact calibration to base year data but the forecasting capacity of the model is affected by necessary but arbitrary assumptions imposed during calibration. In this article, a new PMP variant is presented which is based on less arbitrary assumptions that, from a theoretical point of view, are closer to the actual decision making of the farmer. The PMP variant is evaluated according to the predictions of the bio‐economic farm model, developed within the framework for integrated assessment of agricultural systems in Europe (SEAMLESS). The forecasting capacity of the model calibrated with the standard PMP approach and the alternative PMP variant, respectively, is tested in ex‐post experiments for the arable farm types of Flevoland (the Netherlands) and Midi‐Pyrenees (France). The results of the ex‐post experiments, in which we try to simulate farm responses in 2003 using a model calibrated to 1999 data, show that the alternative PMP variant improves the forecasting capacity of the model in all tested cases.     

Marginal Abatement Cost Curves for UK Agricultural Greenhouse Gas Emissions

This article addresses the challenge of developing a ‘bottom‐up’ marginal abatement cost curve (MACC) for greenhouse gas (GHG) emissions from UK agriculture. An MACC illustrates the costs of specific crop, soil and livestock abatement measures against a ‘business as usual’ scenario. The results indicate that in 2022 under a specific policy scenario, around 5.38 Mt CO₂ equivalent (e) could be abated at negative or zero cost. A further 17% of agricultural GHG emissions (7.85 Mt CO₂e) could be abated at a lower unit cost than the UK Government’s 2022 shadow price of carbon [£34 (tCO₂e)^?1]. The article discusses a range of methodological hurdles that complicate cost‐effectiveness appraisal of abatement in agriculture relative to other sectors.     

Methodological limitations in the evaluation of policies to reduce nitrate leaching from New Zealand agriculture

The land‐use optimisation framework, NZFARM, has been promoted as a tool that can be used to assess the economic and environmental impacts of policy on regional land use. This paper outlines how methodological limitations presently restrict its capacity to provide meaningful insight into the relative value of alternative land‐use configurations. The model is calibrated using positive mathematical programming, which has been shown in the literature to result in models that yield arbitrary output outside of the calibrated baseline. There is a high likelihood that this is the case, as no validation appears to have been carried out. Significant model development will be required before NZFARM outputs can be used with any confidence to inform future policy development. We conclude with suggestions on how NZFARM and models of its kind can be further developed to improve their capacity for meaningful simulation.     

Incorporating risk in a positive mathematical programming framework: a dual approach

In this study we develop a new methodological proposal to incorporate risk into a farm‐level positive mathematical programming (PMP) model. We estimate simultaneously the farm nonlinear cost function and a farmer‐specific coefficient of absolute risk aversion as well as the resource shadow prices. The model is applied to a sample of representative arable crop farms from the Emilia‐Romagna region in Italy. The estimation results confirm the calibration ability of the model and reveal the values of the individual risk aversion coefficients. We use the model to simulate different scenarios of crop price volatility, in order to explore the potential risk management role of an agri‐environmental scheme.     

Spatial Spillovers on Input‐specific Inefficiency of Dutch Arable Farms

Traditional benchmarking implicitly assumes that decision making units operate in isolation from their peers. For arable production systems in particular, this assumption is unlikely to hold in reality. This paper quantifies spatial spillovers on input‐specific inefficiency using data envelopment analysis and a second‐stage bootstrap truncated regression model. The bootstrap algorithm is extended to allow for the estimation of the parameter of the spatial weight matrix, which captures the proximity between producers. The empirical application concerns Dutch arable farms for which latitudes and longitudes are available. The average inefficiency across years was 3.87% for productive inputs and 2.98% for damage abatement inputs under variable returns to scale. For productive inputs technical inefficiency, statistically significant spillover effects from neighbours’ age and their degree of specialisation depended on the type of the spatial weight matrix used (inverse distance or k‐nearest neighbours). Statistically significant spillover effects of subsidy payments were adverse while statistically significant spillover effects from insurance payments were beneficial. For damage abatement inputs technical inefficiency, statistically significant adverse effects were found for neighbours’ age and subsidy payments and beneficial effects from neighbours’ insurance payments and their degree of specialisation.     

The Impacts of Elicitation Context on Stated Preferences for Agricultural Landscapes

Statements of willingness to pay (WTP) have been shown to be dependent upon the framing of the hypothetical market. In this paper we investigate the effects of variations in the timing and location of choice experiment questions concerned with conservation of a UK national park, as research involving measurement of psychological well‐being suggests potential differences for the same individual dependent upon when and where preferences are elicited. We apply the choice experiment technique to the valuation of changes in upland agricultural and semi‐natural landscapes in the Peak District National Park in the UK, to investigate whether timing and location of elicitation (context) affects the value associated with changes in ecosystem services under different management regimes. Four treatments are employed – using the same sample of individuals answering the same choice scenarios – to measure WTP ex‐ante (off site), in situ (on site), and ex‐post at two different time intervals (off site). We show that our on‐site (in situ) treatment generates very different estimates of preferences than any of the off‐site treatments. That stated preferences associated with environmental goods are so context dependent may have implications for the use of stated preferences in policy analysis in terms of identifying how environmental policy is funded and the divergence in value attributed to sampling different populations.     

Modeling regime‐dependent agricultural commodity price volatilities

In stark contrast to financial markets, relatively little attention has been given to modeling agricultural commodity price volatility. In recent years, numerous methodologies with various strengths have been proposed for modeling price volatility in financial markets. We propose using a mixture of normals with unique GARCH processes in each component for modeling agricultural commodity prices. While a normal mixture model is quite flexible and allows for time varying skewness and kurtosis, its biggest strength is that each component can be viewed as a different market regime and thus estimated parameters are more readily interpreted. We apply the proposed model to ten different agricultural commodity weekly cash prices. Both in‐sample fit and out‐of‐sample forecasting tests confirm that the two‐state NM‐GARCH approach performs better than the traditional normal GARCH model. A significant and state‐dependent inverse leverage effect is detected only for pork in the regime where the price is expected to drop, indicating the volatility in this regime tends to increase more following a realized price rise than a realized price drop.     

基于地块单元的冬小麦遥感估产方法研究

[目的]以高分时序遥感影像为基础数据源,结合土地承包经营权地块数据,对冬小麦遥感估产方法及其精度进行研究和分析。[方法]文章以河南省兰考县为研究区,采用2019年4―5月份的GF-1C和GF-6 2 m PMS遥感影像提取了研究区冬小麦种植空间分布,并在地块单元控制下对冬小麦种植面积进行了修正和精度验证。其最优提取结果的修正阈值为0.93,地块单元内冬小麦总体分类精度为95.66%,Kappa系数为0.89。利用3月7日至5月20日6期GF-1 WFV遥感影像序列NDVI和RVI与冬小麦种植地块单元数据进行空间统计,得出各冬小麦种植地块单元内NDVI和RVI均值,通过分析冬小麦测产地块单元内均值植被指数与产量间的敏感性,提出一种组合均值植被指数的冬小麦遥感估产模型构建方法,通过交叉验证法对不同的估产线性回归模型进行精度评价。[结果]由4个均值植被指数组合变量的多元线性回归模型为最佳,决定系数为0.922 0,预测误差为40.96 g/m~2,预测精度为93.13%。通过该模型得出兰考县冬小麦平均产量为6 047.25 kg/hm~2,较2017年河南省统计年鉴研究区冬小麦平均单产6 001 kg/hm~2有所提高,土地承包经营权地块内和地块外冬小麦总产量分别为2.76亿kg和4 650万kg。[结论]该方法实现了冬小麦估产结果以像元为单位向以地块单元为单位的转变,解决了模型构建时光谱信息与实测产量间对应问题,为利用国产高分卫星进行县域地块尺度遥感单产精准化估算提供了方法支撑。     

Optimal Hedging Ratios for Wheat and Barley at the LIFFE: A GARCH Approach

Over 100,000 futures contracts for cereals are traded annually on the London International Financial Futures Exchange. The proportion of the spot position held as futures contracts ‐ the hedging ratio ‐ is critical to traders and traditional estimates, using OLS, are constant over time. In this paper, we estimate time‐varying hedging ratios for wheat and barley contracts using a multivariate generalised autoregressive conditional heteroscedasticity (GARCH) model. Results indicate that GARCH hedging ratios do change through time. Moreover, risk using the GARCH hedge is reduced significantly by around 4 per cent for wheat and 2 per cent for barley relative to the no hedge position, and significantly by around 0.2 per cent relative to the constant hedge. The optimal, expected utility‐maximising, and the risk‐minimising hedging ratios are equivalent.     

Firm behaviour under uncertainty: a simple parametric model

In this paper, we model production technology in a state‐contingent framework. We assume that all the firms use the same stochastic technology, but they may have different risk attitudes and information sets, and ex post they may operate in different production environments. Firms maximise ex ante their preference function subject to a stochastic technology constraint; in other words, they are assumed to act rationally, thereby leaving no room for either technical or allocative inefficiency. We provide a simple parametric functional form to represent the state‐contingent technology. Using simple numerical examples, we illustrate how optimal input–output choices are dramatically affected when firms have different preferences and information sets. Thus, we show that the observed disparateness of production choices among different firms can actually be attributed to the stochastic nature of the decision environment.     

重庆市长寿区旱改水潜力评价与优化研究

[目的]文章以重庆市长寿区为例,对其旱地改水田潜力进行测算,以期提高耕地质量,促进耕地内部结构调整和占补平衡,保障地区粮食安全和生态系统安全。[方法]基于2010—2018年旱改水空间分布特征研究,构建旱改水适宜性评价模型,该模型涵盖地形条件、土壤条件、耕作条件3个评价维度,包括海拔高程、地形坡度、表层土壤质地等10个评价指标。然后利用模型评价旱改水整治潜力,并识别整治的障碍因素,最后基于评价结果,提出旱改水的整治措施建议。[结果]（1） 2010—2018年长寿区旱地改水田整体集中度较高,主要分布在北部和中部地区,其中,密度最高的乡镇是海棠镇、云台镇和葛兰镇。（2）总的来说,重庆市长寿区旱地改水田整体适宜性不高,高度适宜和中度适宜改为水田的旱地面积分别为159.81hm2、8 115.64hm2,两者占全域总面积的25.22%,这些地块主要分布在区域中部、北部的石堰镇、葛兰镇、云台镇等乡镇;勉强适宜和不适宜改为水田的旱地占比为74.78%,这些地块限制性因素较多,难以改造为水田。[结论]综上,未来长寿区可通过改造有效土层厚度低、地形坡度较陡、田块面积小、灌溉保证率低等障碍因素推动耕地...     

Drivers of vertical intra‐industry trade: the case of the Hungarian agri‐food sector

This article investigates the drivers of vertical intra‐industry trade (VIIT) in Hungarian agri‐food trade with the European Union (EU). It identifies three possible ways to measure intra‐industry trade (IIT) flows (GHM, FF, and N methods) and defines six hypotheses to test for the drivers of VIIT with three panel data models (static, dynamic, and FEVD). The results suggest that factor endowments are negatively, while economic size is positively and significantly related to VIIT. Distance and VIIT were found to be negatively related as is commonly the case in the standard gravity model. It was also found that VIIT is greater if a New Member State (NMS) is exporting agri‐food produce to an NMS, while EU accession has ambiguously influenced the share of VIIT. In general, it seems that our results are independent from model estimations and interestingly they do not differ considerably as we a priori expected. Moreover, our results seem surprisingly robust across various measurements of ITT.     

Estimating the range of economic impacts on farms of nutrient leaching reduction policies

Declining agricultural incomes, increasing concern over rural poverty and sporadic crises such as those of Bovine Spongiform Encephalopathy (BSE) and Foot and Mouth Disease mean that the imposition of further costs on U.K. agriculture are likely to be politically and socially sensitive. Such additional costs are however on the agenda with the implementation of the Water Framework Directive (WFD; European Commission, 2000 ). The WFD aims to achieve “good ecological status” in EU water bodies reducing, inter alia, diffuse pollution from agriculture. In this study, we assess four possible WFD measures proposed to the U.K. Department for Environment, Food, and Rural Affairs: reducing inorganic fertilizer application, conversion of arable land to ungrazed grassland, reducing livestock stocking rates, and reducing livestock dietary N and P intakes. For each measure, changes in farm gross margins (FGMs) are estimated using a dataset of over 2000 farms. In contrast to previous analyses, which have focussed upon mean responses on stylized farms, our approach allows the analysis of the range of impacts across a wide variety of real‐world farms and farm types. Findings reveal high variability in impacts. Cost‐effectiveness analysis indicates that, on average, cropping farms seem capable of reducing nutrient leaching in a more cost‐efficient way than livestock or dairy enterprises.     

Market power,market outcomes,and remedies in the UK groceries market

This article describes a number of the issues that played a central role in the UK Competition Commission's investigation into the UK Groceries Sector. We describe the questions at issue, the evidence collected to address those questions, and the conclusions drawn. We go on to describe the CC's remedies both vertically vis‐à‐vis the supply chain and horizontally vis‐à‐vis markets of high local concentration.