Spatial Yield Risk Across Region, Crop and Aggregation Method

A researcher interested in crop yield risk analysis often has to contend with a lack of field- or farm-level data. While spatially aggregated yield data are often readily available from various agencies, aggregation distortions for farm-level analysis may exist. This paper addresses how much aggregation distortion might be expected and whether findings are robust across wheat, canola and flax grown in two central Canadian production regions, differing mainly by rainfall, frost-free growing days and soil type. Using Manitoba Crop Insurance Corporation data from 1980 to 1990, this research, regardless of crop or region analyzed, indicates that (i) spatial patterns in risk are absent; (ii) use of aggregate data overwhelmingly under-estimates field-level yield risk; and (iii) use of a relative risk measure compared to an absolute risk measure leads to slightly less aggregation distortion. Analysts interested in conducting farm-level analysis using aggregate data are offered a range of adjustment factors to adjust for potential bias.     

Crop Price and Risk Effects on Farm Abatement Costs

Potential leaching losses of nitrogen depend in large part on the crops grown. Since crop selection is a major means of abatement for nitrates in groundwater, it follows that the compliance costs to producers for reducing excess nitrogen is influenced by crop prices. This paper demonstrates the role that crop prices play in determining the level of on-farm abatement costs and even the necessity for regulatory policies to deal with the nitrate problem. Government support programs, specifically the Gross Revenue Insurance Program (GRIP), have increased the relative support for corn, which has higher leachate potential than other crops, and thereby requires increased abatement effort. The required level of abatement is less when risk aversion is considered than under risk neutrality, since the variability in returns among rotations is related to the degree of emissions generated. Changes in the mean and variance of relative output prices can significantly alter the optimal crop mix, leachate potential and on-farm abatement efforts. Subsequently, there is an effect on abatement costs associated with alternative environmental control instruments, which in turn affects policy design through issues such as political feasibility and equity considerations.     

Data Aggregation Issues for Crop Yield Risk Analysis

With increased emphasis on risk management in agriculture and a lack of disaggregated or farm‐level yield time series, decision makers are often faced with having to make adjustments to temporal yield risk measures obtained from readily available but aggregated yield data. This paper provides some empirical evidence on what type of aggregation bias to expect when measuring temporal yield risk using yield observations averaged across a region relative to yield risk estimated from quarter‐section yield time series in wheat. This study highlights some of the challenges faced when estimating aggregation distortions in measuring yield risk defined by temporal variance, especially given the nature of the empirical data set used. Cluster analysis, visual examination of relative frequency distributions and mapping of yield risk clusters suggest that using a readily available, aggregate temporal yield risk measure has the tendency to underestimate yield risk observed at the quarter‐section level and that clear, geographic yield risk boundaries do not exist in municipalities or across larger areas in this study. Further research on crops more risky than wheat appears promising. Avec un plus grand intéret sur la gestion du risk dans l'agriculture et un manque de données détaillees ou bien de collections de séries temporelles sur les rendements, les décideurs sont souvent tenus d'apporter des correctifs aux measures du risk obtenues a partir des données de rendements qui sont disponibles. Cet artcle apporte une preuve empirique du type de biais lie a l'agrégation qui peut être présent dans le calcul du risk de rendement temporel obtenu a partir de rendements moyens de blé observés au niveau régional en comparaison du risk de rendement qui est estimé a partir de données basées sur des quart‐de‐sections. Cette étude met en exergue quelques uns des obstacles qui se présentent dans l'estimation de distosions liées a l'aggrégation dans le calcul du risk de rendement défini par la variance temporelle, speciallement étant donne la charactère empirique des données utilisées. L'analyse de groupe, l'examen visual de la distribution des fréquences relatives, et la cartographie de classes de risk de rendement suggèrent que l'utilisation de la measure du risk de rendement basée sur des données disponibles de risk aggrège temporel a tendence a sousestimer le risk de rendement observe au niveau des quart‐de‐sections et qu'il n'y a pas de frontières de risk de rendement certaines, géographiques qui existent entre les municipalités ou bien a travers les zones plus larges examinées dans cette etude.     

Acreage Response to Weather, Yield, and Price

This paper examines the effect of weather on the distribution of yield and its subsequent impact on the acreage allocation decisions of crop farmers in Ontario. The mean and variance of yield are estimated for corn, soybeans, and winter wheat for eight counties in Ontario over a 26-year period. The predicted parameters of the yield distribution are then used along with expectations on the distribution of crop price to estimate area response functions. A principal contribution of the paper is the decomposition of the revenue impact on crop area allocation into separate average and variance contributions for both price and yield. This decomposition illustrates the importance of expected yield in the area allocation decisions. Crop yield is especially influenced by the length of the growing season and this has a significant impact on acreage allocations. This implies that crop area will be altered in response to expected changes in climate, even without shifts in crop prices. Le présent article examine l'incidence des facteurs météorologiques sur la distribution des rendements et leurs conséquences sur les décisions des producteurs agricoles de l'Ontario concernant l'allocation des superficies cultivées. Nous avons estimé la moyenne et la variance des rendements pour le maïs, le soja et le blé d'automne cultivés dans huit comtés ontariens au cours d'une période de 26 ans. Les paramètres prédits de la distribution des rendements et l'espérance de la distribution du prix des cultures ont été utilisés pour estimer les fonctions de réponse par région. La décomposition de l'impact du revenu sur l'allocation des superficies cultivées en terme d'effets sur les moyennes et les variances des prix et des rendements constitue une importante contribution de l'article. Cette décomposition montre l'importance des rendements prévus dans les décisions d'allocation des superficies. Le rendement de culture est particulièrement influencé par la longueur de la saison de croissance qui a une incidence considérable sur l'allocation des superficies cultivées. Par conséquent, les superficies cultivées seront influencées par les changements climatiques prévus, et ce, même en l'absence de fluctuation du prix des cultures.     

A Comparative Evaluation of Yield Risk Reductions with Alternative Crop Insurance Programs in Manitoba

Three crop insurance programs are evaluated in terms of their effectiveness of yield risk reductions for 371 Manitoba farms. The examination is first conducted with a proposed index method, with which the relative yield risk reduction magnitude is calculated and compared for each farm under each alternative program. The generalized stochastic dominance (GSD) methodology is also used to provide an alternative analytical framework in analyzing producers’relative preferences among those alternatives by comparing the net yield distributions generated by each program for each farm. The results suggest that, given an actuarially sound basis, the filly individualized crop insurance (FI) program is the most favorable choice for risk-averse producers. The area coverage and individual indemnity program (IA) is generally the second best option. The full area crop insurance program (FA) is least preferred by risk-averse farmers.     

基于加权马尔柯夫链的粮食单产风险预测——以辽宁省为例

利用随机过程中的马尔柯夫链原理预测粮食单产风险问题。针对粮食年单产量为相依随机变量的特点,提出以规范化的各阶自相关系数为权,运用加权的马尔柯夫链来预测未来粮食年单产量变化状况,并以辽宁省26年统计资料为实例对该方法进行具体应用。     

The Demand for Hedging and the Value of Hedging Opportunities

Hedging strategies typically assume that hedging is costless and that only one futures market exists. When these assumptions are dropped, the demand for hedging is shown to depend on basis risk, price risk, and the hedger's risk preference. The marginal and incremental value of hedging opportunities are computed for the general cases of one and two markets and applied to the specific case of Pennsylvania dairy input hedging.     

Evaluating the Potential of Index Insurance Schemes to Reduce Crop Yield Risk in an Arid Region

We evaluate yield risk reduction through weather index, area yield index and farm yield insurance contracts for wheat farms in Kazakhstan by employing data from 1980 to 2002. We use the usual mean variance (MV) approach and also a second‐degree stochastic dominance (SSD) criterion. While MV is not necessarily consistent with the expected utility (EU) theory, SSD results only in a minimum but EU‐consistent benefit from insuring. Differences in the estimation results for both approaches underline the advantage of applying both criteria to analyse the risk‐reducing potential of crop insurance. Bootstrapping results show that none of the analysed insurance schemes provides statistically significant risk reduction for every single farm. In addition, weather‐based index insurance is found to provide less risk reduction than area yield insurance based on the rayon (county) yield. Moreover, rayon yield index insurance can reduce yield risk more effectively for Kazakhstan's wheat producers than farm yield insurance with a low strike yield.     

The Impact of Price Stabilizing Policies on the Risk Efficient Crop/Fallow Decisions of Wheat Farmers in the Brown Soil Zone of Saskatchewan

The micro-linkages between the crop/fallow decision and price-induced risk are examined for wheat producers located on the brown soils of Saskatchewan. Three generic price stabilization policies are defined. Based on a bio-economic simulation model, the risk-efficient FLEXCROP decision rules are selected, and their corresponding cropping patterns are assessed for each generic price stabilization policy. Assuming no subsidy component within the mandatory price stabilization program:
• risk lovers reduce cropped acreages by 0% to 4%, depending upon both the risk-aversion level and the stabilizing program and
• risk-averse producers increase cropped acreage from 10% to 35% over no price stabilization.     

On Crop Biodiversity, Risk Exposure, and Food Security in the Highlands of Ethiopia

This paper investigates the effects of crop genetic diversity on farm productivity and production risk in the highlands of Ethiopia. Using a moment-based approach, the analysis uses a stochastic production function capturing mean, variance, and skewness effects. Welfare implications of diversity are evaluated using a certainty equivalent, measured as expected income minus a risk premium (reflecting the cost of risk). We find that the effect of diversity on skewness dominates its effect on variance, meaning that diversity reduces the cost of risk. The analysis also shows that the beneficial effects of diversity become of greater value in degraded land.     

Crop Yield Skewness Under Law of the Minimum Technology

No satisfactory motivation has been forwarded in favor of any crop yield distribution, including the normal. This article explores the foundations of yield distributions for the Law of the Minimum resource constraint technology at the plot level of analysis. With independent, identical, uniform resource availability distributions the yield skew is positive, whereas it is negative whenever the distributions are normal. Simulations show how asymmetries in resource availabilities determine skewness. It is suggested that a negative yield skew occurs whenever production is tightly controlled so that the left tails of some resources availabilities distributions are thin. Irrigation may increase yield skewness.     

Pre-Harvest Price Expectations for Corn: The Information Content of USDA Reports and New Crop Futures

This article examines the puzzle of why futures prices continue to react to USDA crop reports despite the fact that reports appear to be no longer "newsworthy," that is, provide no better production estimates than private forecasts. The information value of reports is measured in terms of their influence on rational agents' harvest-time corn price expectations, which are uncovered using a Hamilton-type modeling approach. Results show that reports are still "newsworthy," as they would contribute to agents' price expectations if released a day early. Thus futures price reactions, which closely reflect price expectations, are rational and consistent with efficient markets hypothesis.     

Optimal Input Use When Inputs Affect Price and Yield

Input use has been shown to impact the variance of output and therefore risk. When inputs affect both output level and the price of the output, the variance of revenue and profit depend on each effect and their interactions. We analyze the effect of nitrogen (N) use rate applied to wheat on the variance of yield, revenue, and the price of wheat, when protein premiums (discounts) are applied. We find that N use rate increases the variance of yield, but reduces the variance of price. The net effect of N use rate on revenue and profit is variance increasing, but the variance effect is less than for yield alone. Optimal rates of N are about 60% higher with protein payments compared with a constant wheat price over all protein levels. Risk-averse producers apply less N than risk-neutral producers but, because revenue and profit risk is lower with protein payments, the reduction in N is less than if based on a constant price over all protein levels.     

A Risk Efficiency Analysis of Crop Rotations in Saskatchewan

Spring wheat and fallow have dominated land use practices in Saskatchewan for the 1971–85 period, despite the urgings of soil scientists, crop scientists and agricultural economists to reduce fallow area and to diversify into other crops. This paper demonstrates that if production and marketing risks associated with various rotations are considered, there is close correspondence between rotations that are selected via stochastic dominance and actual producer behavior with respect to fallow use in crop rotations. Gross margins for a number of hypothetical rotations are calculated for the 1971–85 period and are analyzed using stochastic dominance and mean-variance trade-off criteria. Resulting risk efficient sets are found to be a reasonable explanation of actual producer behavior over the time period examined. La culture du blé de printemps et la jachére ont dominé les pratiques d'utilisation des terres en Saskatchewan pendant la période de 1971 à 1985, malgre les interventions des spécia-listes des sols et des cultures et des éconornistes agricoles en faveur d'une reduction des superficies laissees en jachere et d'une diversification des cultures. Dans le présent article, nous démontrons que si I'on tient compte des risques de production et de commercialisation inherents a divers types de rotation, il existe une correspondance étroite entre les rotations choisies par voie de dominance stochastique et le comportement réel du producteur face au recours a la jachire dans la rotation des cultures. Nous avons calcule les profits bruts cor-respondant é un certain nombre de rotations hypothétiques pour la période de 1971 a 1985 et nous en avons fait I'analyse á I'aide du critére de la dominance stochastique et du critere du compromis de la variance moyenne. Les valeurs de I'efficacité du risque que nous en avons tirées ont permis de fournir une explication raisonnable du comportement réel des producteurs pendant la période de temps étudiée.     

Martingale Restrictions and the Implied Market Price of Risk

The market price of risk is conceptually one of the most critical artifacts of modern finance, since it provides the linkage between equilibrium and arbitrage models of derivatives pricing. In this paper, the market price of risk is derived for options on live cattle futures contracts. It provides a technique to extract the implied market price of risk (iMPR), which is conceptually similar to that used in extracting implied volatilities. It is shown that the iMPR is not linear across strike prices as theory suggests it should.
Le prix de marché du risque est conceptuellement l'un des artéfacts les plus importants de la finance moderne puisqu'il établit le lien entre les modèles d'équilibre et les modèles d'évaluation par arbitrage de l'établissement des prix des dérivés. Dans le présent article, le prix de marché du risque est dérivé pour les options sur contrats à terme de bovins vivants. Il offre une technique pour extraire le prix de marché implicite du risque qui est conceptuellement similaire à celle utilisée pour extraire les volatilités implicites. Il est montré que le prix de marché implicite du risque n'est pas linéaire pour tous les prix de levée comme la théorie semble l'indiquer.