Bayesian Estimation and Selection of Nonlinear Vector Error Correction Models: The Case of the Sugar-Ethanol-Oil Nexus in Brazil

Nonlinear adjustment toward long-run price equilibrium relationships in the sugar-ethanol-oil nexus in Brazil is examined. We develop generalized bivariate error correction models that allow for cointegration between sugar, ethanol, and oil prices, where dynamic adjustments are potentially nonlinear functions of the disequilibrium errors. A range of models are estimated using Bayesian Monte Carlo Markov Chain algorithms and compared using Bayesian model selection methods. The results suggest that the long-run drivers of Brazilian sugar prices are oil prices and that there are nonlinearities in the adjustment processes of sugar and ethanol prices to oil price but linear adjustment between ethanol and sugar prices.     

The linkage between the U.S. ethanol market and developing countries’ maize prices: a panel SVAR analysis

The major expansion of U.S. ethanol production raises concerns about the potential detrimental impacts on developing countries’ agricultural prices, farm income, and food security. To assess the sensitivity of maize prices to ethanol production, this study explores the linkage between the U.S. ethanol market and developing countries’ maize prices. The econometric approach, based on a panel structural vector autoregression model, captures market interdependencies and the likelihood that developing countries’ responses are both heterogeneous and dynamic. The results indicate that the U.S. ethanol market's impacts on maize prices in developing countries are heterogeneous and that coastal countries are more susceptible to U.S. economic shocks. The estimates also suggest that countries more dependent on food imports and/or receiving U.S. food aid are at a higher risk of being affected by such shocks. Overall, the results indicate that those countries with the greatest sensitivity and exposure to global agricultural commodity markets could benefit from domestic policies and international assistance, which reduce their exposure to impacts from the U.S. maize market.     

A hybrid commodity price‐forecasting model applied to the sugar–alcohol sector

Accurate price forecasting for agricultural commodities can have significant decision‐making implications for suppliers, especially those of biofuels, where the agriculture and energy sectors intersect. Environmental pressures and high oil prices affect demand for biofuels and have reignited the discussion about effects on food prices. Suppliers in the sugar–alcohol sector need to decide the ideal proportion of ethanol and sugar to optimise their financial strategy. Prices can be affected by exogenous factors, such as exchange rates and interest rates, as well as non‐observable variables like the convenience yield, which is related to supply shortages. The literature generally uses two approaches: artificial neural networks (ANNs), which are recognised as being in the forefront of exogenous‐variable analysis, and stochastic models such as the Kalman filter, which is able to account for non‐observable variables. This article proposes a hybrid model for forecasting the prices of agricultural commodities that is built upon both approaches and is applied to forecast the price of sugar. The Kalman filter considers the structure of the stochastic process that describes the evolution of prices. Neural networks allow variables that can impact asset prices in an indirect, nonlinear way, what cannot be incorporated easily into traditional econometric models.     

The Incidence of EU Per‐Hectare Payments on Farmland Rental Rates: A Spatial Econometric Analysis of German Farm‐Level Data

This article analyses determinants for 2001 farmland rental prices from 3,819 farms in Germany. Based on specification tests we estimate a general spatial model to account for both spatial relationships among rental prices of neighbouring farmers and spatially autocorrelated error terms. A €1 per hectare higher rental price in a farmer’s neighbourhood coincides with a €0.72 higher rental price paid by the farmer. The marginal incidence of EU per‐hectare payments paid for eligible arable crop land on rental rates amounts to €0.38 for each additional €1 of premium payments. Regional livestock density, which is indirectly influenced by different policies, is also a major determinant of rental prices. Results are confirmed by sensitivity analyses. Consequently, German farmland rental rates are heavily influenced by agricultural policy instruments and therefore, these policies exhibit substantial distributional effects.     

Price shock transmission: evidence from the wheat‐bread market value chain in Ethiopia

This study assesses the degree of vertical price transmission along the wheat‐bread value chain in Ethiopia. This is pursued by applying a vector error correction model and an impulse response analysis using monthly price data for the period 2000–2015. Our analysis considers transmission of price shocks across different market levels, including from the international and domestic wheat grain markets at the upstream to the domestic wheat bread market at the downstream of the value chain. The empirical findings indicate that significant cointegration exists across prices of the different market stages. There is a transmission from international prices to domestic prices at downstream markets, in particular to flour and bread prices. Prices at upstream markets are largely influenced by the domestic wholesale market. In general, the speed of adjustment is quite slow with a half‐life of about one year for restoring the equilibrium price relationship. As price margins between the different market stages in the value chain have substantially decreased in the last 15 years, higher transmission, and thus exposure to international market shocks, can be expected in the future. The results also show that causal relationships exist between prices at different market stages—with the wholesale market identified as the key market level where prices and price expectations are formed.     

A Spatio‐temporal Model of Farmland Values

Despite the fact that data on farm sales are invariably collected over both time and space, previous papers have allowed for the presence of either temporal or spatial relationships in the data, but not both. Some papers have also inadvertently assumed that although farmland values are influenced by prices realised by nearby sales, these sales need not necessarily be comparable in terms of their attributes. Using data on sales of farmland obtained through public auctions in England and Wales, this paper examines the consequences of explicitly allowing for the presence of a spatio‐temporal lag in the estimation of hedonic models of farmland value. The results indicate that spatio‐temporally lagged values of the dependent and independent variables contribute significant additional explanatory power. Accounting for spatio‐temporal relationships appears moreover to somewhat alter the perceived size and statistical significance of key farmland attributes.     

A Note on Tests for Market Integration in a Multivariate Non‐Stationary Framework

In this note relationships among agricultural prices are studied to offer a guide to the degree of market integration. Unlike many previous studies, which examine market integration using pairs of prices, we conduct testing in a multivariate framework to exploit the information embodied in the indirect price linkages. We focus on the formulation of hypotheses that identify the cointegration space using time series data on European pork and lamb markets. Results indicate that the national markets for pork are more closely integrated than those for lamb. Extraneous market information is exploited in an attempt to identify the cause of this segmentation in the European lamb market, although results do not support any of the hypotheses proposed.     

Long‐Run Drift,Co‐Movement and Persistence in Real Wheat and Maize Prices

Trends in real prices for food commodities are both important and controversial. Paying particular attention to issues of methodology, this paper assesses the evidence for a downward drift in the real prices of wheat and maize. It is found that the apparent strength of that evidence depends substantially on whether the time series generating models are taken to be trend‐stationary or difference‐stationary, and on whether allowance is made, through incorporation of dummy variables in the models, for events in one or two extreme years. Once dummy variables are incorporated, we find little evidence against difference‐stationarity. The analysis then proceeds, through tests for cointegration, to the construction of error‐correction models linking the two prices and to the estimation of persistence of shocks in this bivariate framework. The paper presents modest evidence for downward drift in real grain prices of about 1 to 1.5 per cent per annum, shows that wheat and maize prices cointegrate and estimates that direct and cross‐persistence measures take values of less than unity.     

Measuring the Impact of Ethanol Plants on Local Grain Prices

A considerable number of farmer-owned ethanol plants have been built in the past few years, with many more planned. In part, farmers' investment in ethanol plants is an attempt to increase grain prices in their local market. We examined this issue by estimating the impact on local grain prices of twelve ethanol plants that opened from 2001 to 2002. We find that these new ethanol plants increased local grain prices, but the impact was not uniform around the plant. Markets downstream from a new plant, where prices tend to be higher, experienced a smaller price impact from the ethanol plant. On average across plants, corn prices increased by 12.5 cents per bushel at the plant site, and some positive price response was felt 68 miles away from the plant.     

Price formation in the German biodiesel supply chain: a Markov‐switching vector error‐correction modeling approach

Changing linkages between agricultural and energy markets have attracted considerable attention in research and policy discussions during recent years. As one of the largest biofuel markets worldwide, the German biodiesel market is of particular interest. It has grown rapidly since the beginning of the new millennium, with this growth being driven mainly by political interventions. Vertical price transmission channels along the biodiesel supply chain are analyzed in this study. We examine the relationship between diesel and biodiesel prices, and between rapeseed oil, soy oil, and biodiesel prices between 2002 and 2008. Due to pronounced changes in market conditions and the policy framework, a regime‐dependent Markov‐switching vector error‐correction model is used. The regimes are characterized by markedly different price adjustment behaviors. Before 2005 and from late 2007 onward, a regime characterized by the strong orientation of biodiesel prices toward diesel prices dominates. Between 2005 and 2007, biodiesel and rapeseed oil prices are mutually interdependent. Frequent switches between the regimes of the price dynamics during this period indicate a high extent of uncertainty and instability in the market.     

Crop‐Level Supply Response by Agro‐Climatic Region in Ethiopia

Using farm‐level survey data from Ethiopia, this paper estimates a quadratic restricted profit function to assess the supply response of smallholder farmers. All major crops are identified in the analysis and variations in agro‐climatic and farming systems are accounted for. Peasant farmers, at least in the more commercial Central and Southern zones, do respond positively and significantly to price incentives. Farmers in the Northern zone are least commercial and least responsive to prices, and in fact the model based on profit maximisation does not adequately capture their behaviour. In general, non‐price factors, especially rainfall and market access, are more important than prices in affecting poduction, and which factors are most important varies depending on the crop and region in question. We conclude with suggestions regarding which crops appear most suitable to each agro‐climatic region, and identify the most relevant policy interventions in each case.     

Out‐of‐sample testing price discovery in commodity markets: the case of soybeans

Price discovery, a central function of futures markets, has been usually tested in‐sample by studying the common stochastic trend between spot and futures prices. Instead, to evaluate futures as anticipatory prices, we develop a forecast approach to out‐of‐sample test price discovery in a multivariate framework. We apply it to the soybeans market. Results indicate futures prices as the best available “predictors” of future spot prices, although this finding holds only on average and for certain periods, other models show forecasting gains.     

Energy‐milk price transmission at the product brand level

This article estimates the pass‐through rates between diesel fuel and retail milk prices at the product brand level. Using a random coefficient logit demand model and taking the direct and indirect impacts of energy prices, this research identifies changes in pass‐through rates before and after the great recession in 2008. Empirical results show that diesel prices significantly impacted the retail prices of milk products and are an important determinant of food price inflation. Pass‐through rates are estimated to range from 0.16 to approximately 0.60 through 2008 with an average of 0.22 for the whole period. Statistical tests indicate that pass‐through rates before June 2008 were significantly higher than after June 2008 when they dropped significantly to 0.04 to 0.17. Interestingly, private label brands have the lowest pass‐through rates, implying that compared to manufacturer brands, private label prices are more insulated from diesel price shocks.     

A speculative bubble in commodity futures prices? Cross‐sectional evidence

Recent accusations against speculators in general and long-only commodity index funds in particular include: increasing market volatility, distorting historical price relationships, and fueling a rapid increase and decrease in the level of commodity prices. Some researchers have argued that these market participants—through their impact on market prices—may have inadvertently prevented the efficient distribution of food aid to deserving groups. Certainly, this result—if substantiated—would counter the classical argument that speculators make prices more efficient and thus improve the economic efficiency of the food marketing system. Given the very important policy implications, it is crucial to develop a more thorough understanding of long-only index funds and their potential market impact. Here, we review the criticisms (and rebuttals) levied against (and for) commodity index funds in recent U.S. Congressional testimonies. Then, additional empirical evidence is added regarding cross-sectional market returns and the relative levels of long-only index fund participation in 12 commodity futures markets. The empirical results provide scant evidence that long-only index funds impact returns across commodity futures markets.     

Impacts of the End of the Coffee Export Quota System on International‐to‐Retail Price Transmission

We examine the impact of the end of the coffee export quota system (EQS) on international‐to‐retail price transmission in France, Germany and the United States. We take account of the existence of long‐run threshold effects and short‐run price transmission asymmetries (PTAs). We find evidence of threshold effects in both periods (EQS and post‐EQS) in all three countries and the presence of short‐run PTAs during the post‐EQS period in all countries, but not during the EQS period. Our results indicate that the threshold values are smaller in the post‐EQS period, suggesting that retail prices became more responsive to changes in international prices. However, the speed of adjustment towards the long‐run equilibrium decreases during the post‐EQS period in the three countries. In the short run, non‐linear impulse response analyses indicate that a shock in international prices was more persistent during the EQS period than in the post‐EQS period. Moreover, we find evidence of short‐run PTAs in the post‐EQS period, with differences across countries. We find support for the ‘rockets and feathers’ principle in the United States; in contrast, retail prices respond faster when international prices are falling in Germany and France. We explain these differences in terms of market structures.     

Inter‐ and intra‐seasonal crop acreage response to international food prices and implications of volatility

Understanding how producers make decisions to allot acreage among crops and how decisions about land use are affected by changes in prices and their volatility is fundamental for predicting the supply of staple crops and, hence, assessing the global food supply situation. This study makes estimations of monthly (i.e., seasonal) versus annual global acreage response models for the world's principal staple food crops: wheat, corn, soybeans, and rice. Primary emphasis is given to the magnitude and speed of the allocation process. Estimation of intra‐annual acreage elasticity is crucial for expected food supply and for input demand, especially in the light of the recent short‐term volatility in food prices. The econometric results indicate that global crop acreage responds to crop prices and price risks, input costs as well as a time trend. Depending on respective crop, short‐run elasticities are about 0.05 to 0.40; price volatility tends to reduce acreage for some of the crops; comparison of the annual and the monthly acreage response elasticities suggests that acreage adjusts seasonally around the globe to new information and expectations. Given the seasonality of agriculture, time is of an essence for acreage response. The analysis indicates that acreage allocation is more sensitive to prices in the northern hemisphere spring than in winter and the response varies across months.     

When the theory is not enough - valuation of forest resources with “efficiency” prices in practice

In resource accounting, simple theoretical models built upon efficiency prices have been developed to capture changes in social welfare generated by natural resources. We examine whether changes in market stumpage prices, as proxies for efficiency prices, have actually reflected changes in the physical timber inventories in Finland and Sweden during the past seventy years. Cointegration and unit root tests show that no long-term equilibrium relationships exist between the timber prices and stocks. After identifying a potential reason for the result, the basic theoretical growth model is slightly elaborated to provide a more appropriate framework for measuring net domestic product for the forest sector.     

Cost‐reflective pricing: empirical insights into irrigators’ preferences for water tariffs

Using prices to improve the efficiency with which water resources are allocated is now widely accepted in principle if somewhat difficult to achieve in practice. Whilst there are some technical difficulties associated with full‐cost recovery in irrigation, the lack of political will to tackle reform remains a significant impediment. This article reports the results of an empirical investigation into farmers’ preferences for changes to water prices and tariff structures. We conclude that some of the preferences of farmers are conducive to price reform. We also find evidence that public subsidy of infrastructure in irrigation is not always aligned with the preferences of farmers.     

The integration of energy and agricultural markets

This article addresses the evolving links between energy and agricultural markets. Prior to 2005, there was little correlation between energy and agricultural commodity prices. In 2006–2008, with the ethanol boom in the United States, there emerged a strong link between crude oil, gasoline, and corn prices. There was little link between ethanol and corn. However, in late 2008 and 2009, the markets changed as ethanol production came under severe economic pressure and 2 billion out of 12 billion gallons of capacity shut down. During this period ethanol became priced more on corn, as the breakeven corn price helped drive the ethanol market. This article explores the drivers in these markets as well as other major issues facing the corn ethanol industry in the United States such as the blend wall. The article concludes with a review of prospects of a future cellulosic biofuels industry.     

Food security,the labor market,and poverty in the Brazilian bio‐economy

This article deals with the social implications of ethanol expansion in Brazil. The evolution of the labor market in sugarcane production in the country is analyzed together with its regional patterns of expansion, to illustrate how changes in the recent expansion are modifying the traditional pattern of labor demand in the activity. At the same time, the distributional effects of sugarcane expansion, as well as it's impacts on food security and land use change was approached with the aid of general equilibrium simulation models. The analysis shows that both the average earnings and the average years of schooling in sugarcane production are actually higher than in general agriculture in Brazil, and that this is linked to the growing increase in production in the Southeast and Central‐West. Sugarcane production in these regions is more capital intensive and has a much higher productivity than in other traditional regions in Northeast Brazil. The study concludes that the expansion in sugarcane production according to actual patterns does not have a negative effect on poverty, and has only minor impacts on food prices and deforestation. The increase in the regional economic imbalances within the country appears to be the problem that requires attention.