DO INCREASED COMMODITY PRICES LEAD TO MORE OR LESS SOIL DEGRADATION?

In this paper, a dynamic economic model is used to analyze the conflicting impacts of crop increasing/land degrading inputs with those of soil conserving/crop reducing inputs in problems of soil degradation in agriculture. Soil is a renewable resource that is generated naturally at a slow, essentially autonomous rate. Cultivation enhances crop production and degrades the soil, while conservation is unproductive for the crop but improves the soil resource. If the effects of cultivation dominate the effects of conservation in the soil dynamics, an increase in the price of the crop accelerates the rate of soil degradation In the short-run and decreases the long-run stock of the soil resource. On the other hand, if the effects of conservation dominate the effects of cultivation, an increase in the price of the crop decelerates the rate of soil degradation in the short run and increases the long-run stock of the soil resource. It is shown that subsidies on conservation activities or taxes on cultivation intensity may well decrease the long-run soil stock, although strong conditions must be satisfied for either of these results to hold. It also is shown that a reduction in the real discount rate or a direct per unit tax on soil losses is certain to increase the long-run soil stock and reduce the short-run rate of soil degradation.     

NEGATIVE SUPPLY RESPONSE AND THE ROLE OF PRICE EXPECTATIONS IN A TWO-PERIOD MODEL OF CATTLE PRODUCTION

This paper incorporates a representation of producers' price expectations (ARIMA) in a two-period production process to characterise short-run cattle supply. The model provides a framework for examining the role of biological factors and changing expectations of future cattle prices in generating a negative short-run supply response. The biological link between cattle generations requires the farmer to make a decision between production today and production tomorrow. This decision is based on a trade-off between the possibilities of increasing current profit levels by increasing current output weighted against the possibilities of increased future profit by maintaining animals in inventory under the expectation of future price increases. Application of the model to Canadian data for the period 1978-81 shows that the necessary condition for a negative supply response exists, but that the total supply elasticity remains positive.     

INSTABILITY IN WORLD GRAIN MARKETS

The paper discusses the nature of international price variability for wheat and coarse grains. In particular, it explores the relationship between variability in national grain markets and international trade. Empirical evidence is presented on the degree to which short-run fluctuations in domestic grain production are transmitted to the world market by major countries or country aggregates, and on their absorption of international market variability. The impact of possible structural or policy changes upon future international price variability is explored. It is argued that multilateral action to promote greater international stability should focus on the modification of domestic storage policies to reduce the transmission of short-run domestic fluctuations in supply or demand to world markets.     

Forecasting agricultural production using co-integration analysis

A forecasting method, easily understood and applied by administrators/policy-makers, is developed in this paper. Based on a simple, but quite realistic assumption, that production in a given region ‘pulls’ or ‘shapes’ the volume of production nationally a co-integration forecasting method is proposed in the paper. Using data from administrative regions, the empirical analysis suggests that the property of co-integration can be used to forecast agricultural production in the short-run.     

The Determination of Agricultural Wage Rates in Bangladesh

The impact of the ‘green revolution’ on wages has been a contentious issue. This paper uses the cointegration and error correction approach to identify long and short-run relationships between prices, agricultural production and wages of agricultural labourers in Bangladesh, test for homogeneity, test for weak exogeneity with the Johansen-Juselius methodology, test for a structural break, and estimate the long and short-run elasticities of nominal wages with respect to rice prices. We find that agricultural wages have strong positive long run relationships with rice prices, manufacturing wages and agricultural productivity. The short run response of wages, estimated consistently with these longer run relationships, to rice prices is small, highlighting the vulnerability of the rural poor to sudden rises in rice prices, even though in the longer run nominal wages respond sufficiently to rice prices. Policy can promote growth of agriculture and manufacturing but should also mitigate the short run food insecurity of agricultural labourers.     

Dynamic adjustment in the US beef market with imports

This paper hypothesizes that while there are important qualitative differences in domestic beef and imported beef, beef and cattle imports also represent attempts by the US beef processing and wholesale sector to adjust to short-run changes in supply and demand. Dynamic production theory is applied to the problem to test for this adjustment process, and presents a production theory approach to meat trade that has previously been included in demand functions. The results of this analysis suggest that the method used provides a reasonable and appropriate representation of the import behavior of the US processing and wholesale beef sector.     

世界农产品价格波动的新态势:动因和趋势探讨

本文探讨了引发近年世界农产品价格新态势的主要动因,分析了影响农产品价格波动的短期因素和决定其长期趋势的动因.促成近年农产品价格暴涨的主要因素是用粮食生产能源创造了新的需求;而跨国公司控制市场、国际基金参与和投机农产品贸易放大了新需求的影响,并造成了价格前所未有的的急剧波动.虽然决定价格趋势的世界农业生产潜力并没有改变,但农业生产资料价格的上涨拉动生产成本攀升,如果继续扩张用粮食生产能源,世界农产品价格长期下降的趋势将逆转并继续在高住上运行.中国作为世界最大的农产品生产国和消费国,夯实农业生产基础,防止城市无度扩张占用耕地,提倡节约粮食,尤其是在从收获到消费整个环节中减少浪费粮食,同时提高农业贸易的经济效率,是应对世界农产品价格趋高和急剧波动的基本对策.     

Alternative models of input allocation in multicrop systems: Irrigation water in the Central Plains,United States

This paper compares three models of input allocation in multicrop systems. In addition to the variable input and satisficing models analyzed in previous research, an allocatable fixed input model of short-run input use is derived. The empirical application studies irrigation water use in the Central Plains region of the United States. Based on results from model specification tests and prediction accuracy measures, the allocatable fixed input model dominates both other models in explaining multicrop water allocation. In addition, the paper presents an alternative approach to the study of deficient data on multicrop production. By transferring econometric results from analysis of ‘non-deficient’ crop-level data, input allocations in deficient data sets can be predicted.     

Short-run Dynamics of Machinery Demand in Canadian Agriculture

Based on the hypothesis of intertemporal cost minimization, this paper develops an error correction model to explain short-run dynamics of machinery demand in aggregate Canadian agricultural production. The estimated model is subjected to a rigorous sequence of hypothesis tests to check for its statistical validity. In addition, various versions of the model that are nested within the most general model are also tested. Structural parameters of the intertemporal cost minimization problem are recovered from the parameter estimates.     

Allocable fixed inputs as a cause of joint production: an empirical investigation

Leathers (1991) shows that while the existence of allocable fixed inputs can cause joint production (as in Shumway, Pope and Nash, 1984), it will not necessarily lead to joint production. The extent to which allocable fixed inputs cause joint production in agriculture is an empirical question. This paper offers an empirical answer. By estimating a short-run joint cost function, it is possible to identify levels of outputs for which joint production may be optimal in the short run but not in the long run. Only in these output regions will there be jointness caused by allocable fixed inputs. For the data in this paper (160 Wisconsin farms), these output regions are very small; thus allocable fixed inputs do not appear to be an important cause of jointness for these farms. Technical causes of jointness appear to be a significant cause of joint production.     

Agriculture, pesticides and the ecosystem

Economists have a good understanding of intra-economic interdependence and a mature methodology of modelling it. Ecologists focus on the complex and sensitive interactions of species in ecosystems. This paper’s objective is to suggest a new micro-foundation of ecosystem analysis based on economic methodology, to integrate the analyses of the ecosystem and the economy and focus on the interface of ecosystem-economy relations. Agriculture forms a major part of this interface. The basic assumption is that in the short run the individual organisms of all species behave as if they optimise their costly offensive and defensive activities given other organisms’ activities (Nash-behaviour).We consider an ecosystem with three species in a unidirectional food chain: buzzards feed on mice, mice feed on grain, and grain feeds on solar energy. A fourth species, humans, also feeds on grain. Humans intervene in the ecosystem in various ways. They can grow grain by using seed, farm labour, pesticides and possibly nature conservation measures to maintain buzzard habitat. Short-run ecosystem equilibrium is characterised, and it is shown, in particular, how this equilibrium depends on farming activities. We then link this ecosystem model to a simple model of an agricultural economy. Both systems are solved for equilibrium simultaneously. From an economic perspective the ecosystem induces positive and negative externalities in agricultural production and in consumer ‘green’ preferences.The inefficiencies of the competitive economy are identified and some possibilities to restore efficiency through corrective taxes or subsidies are briefly discussed. We also outline how short-run equilibria are connected through ecosystem stock-flow relationships. Due to the complexity of the inter-temporal analysis, the resulting ecosystem dynamics cannot be characterised in general analytical terms. It is a topic for future research to study the dynamics in numerical analysis to understand under which conditions the joint ecological and economic system is driven toward a (sustainable) steady state.     

Dynamic Efficiency Measurement: Theory and Application

Nonparametric dynamic measures of production efficiency are developed in the context of an adjustment-cost technology and intertemporal cost minimization. Bounds on each efficiency measure are derived for each firm using a nonparametric revealed preference approach. Long-run efficiency measures indicate the relative efficiency of both variable and dynamic factors while short-run measures of efficiency indicate whether variable inputs are employed efficiently in the production process. The efficiency measures are temporal in nature by describing the degree of efficiency of the firm at a particular point along its adjustment path. The empirical implementation is illustrated for a balanced panel of Pennsylvania dairy operators during 1986–1992.     

The nature of the research-induced supply shift

Differences among firms in a competitive industry can affect the shape of the industry supply curve. It is necessary to know how both production costs and rents are affected by research. Industry response to research will be different depending upon whether entry occurs. If the effect of entry is ignored, then the price decline from research will be overstated. Industry marginal returns can be positive with purely yield-increasing research, even when industry demand is inelastic. Standard formulas for calculating producer surplus based on linear industry supply and demand curves are strictly valid only if the analysis is restricted to short-run equilibrium behaviour.     

Short-Run Output Response in the Western Canadian Cattle Industry

This paper present the results of recent empirical work on the short-run producetion flexibility of cow-calf producers in Western Canada. Several aspects of firm behaviour may be inferred from the econometric estimates, including short-run elasticities of supply and factor demand, and the total elasticity of cattle supply. The principal empirical findings are that many of the shourt-run supply and factor demand responses of firms, are elastic with respect to within-season price variability. The evidence does not support a vertical or negatively-sloped short-run supply curve for cattle, where one previously has been hypothesized in the theoretical literature.     

Renewable Resources with Endogenous Age Classes and Allocation of Land

It is shown that if it is optimal to allocate all land to forestry, the long-run stationary state is a cyclical solution around an equilibrium with an even timber flow. The equilibrium cycles vanish when it is optimal to allocate some fraction of land outside forestry. We present numerical examples on the transitional dynamics and long- and short-run timber supply. When land conversion is costly, the cycles do not vanish and the long-run equilibrium between forestry and agriculture is represented by a continuum.     

Structural changes in Swedish wastepaper demand: a variable cost function approach

The primary purpose of this paper is to analyse the short-run price responsiveness of wastepaper demand in Sweden for four different paper and board products, as well as any structural changes in demand behaviour for these products over time. The analysis is done within a variable Translog cost function model, and we employ data for individual paper and board mills over the time period 1974-1994. The results suggest that the short-run own-price sensitivity of waste paper demand is relatively high compared to those of other input factors, and it has also tended to increase over time for some of the paper products. In addition, wastepaper demand has also become more sensitive to changes in energy prices, and its use increases with increases in the price of energy. However, the relationship between wastepaper and woodpulp is more complex, and in many instances wastepaper and woodpulp are short-run complements. Overall this implies that price based recycling policies will be relatively successful in promoting wastepaper use, but they will not necessarily lead to the conservation of virgin forest resources.     

Fungicide use under risk in Swiss wheat production

The short-run effects of fungicide application on economic risk and the effects of risk on fungicide use in Swiss wheat production are empirically explored. A quadratic production function model is developed. With the help of the moment-based approach, marginal contributions of fungicides (representing controlled inputs) and of rain (representing uncontrolled inputs) to the variances of yield and revenue are analyzed. It is not possible to show risk-reducing effects of fungicides on yield or revenue. At low rain quantities during the vegetation period fungicides have a statistically significant risk-increasing effect on revenue. Increasing risk leads Swiss wheat growers to use more fungicide. This increase is statistically significant at higher levels of revenue. For example, when risk is doubled fungicide inputs are raised by 44% at the highest revenue quartile.     

2003年以来中国土地政策参与宏观调控的实践——特点、效果以及存在问题的经验总结

研究目的：分析2003年下半年以来中国土地宏观调控的特点、成效以及存在问题。研究方法：描述分析和政策分析方法。研究结果：（1）新一轮宏观调控具有综合运用多种政策工具、尝试采用土地政策、经济手段与行政手段并用、“治标”兼“治本”以及调控及时,力度得当等特点。（2）调控取得初步成效,紧缩的供地政策对抑制投资过快增长,防范可能出现的经济过热起到了一定作用。（3）存在的主要问题：土地政策的运用并非积极主动的;某些政策的执行效果不理想;很多政策以短期措施为主,并且强调集中控制;政策的时滞效应显著。研究结论：对2003年以来中国宏观调控经验的总结表明,土地政策可以作为宏观调控的一个工具,但是具体如何使用还应继续深入研究。     

Identifying Macroeconomic Linkages to U.S. Agricultural Trade Balance

This study explores the short-run and long-run relationships between the U.S. agricultural trade balance and domestic macroeconomic aggregates and agricultural variables. We use cointegration analysis and a vector error-correction model with quarterly data for 1981–2003. The results show that, in the long run, the exchange rate, agricultural price, and disposable income are weakly exogenous in the U.S. agricultural sector and have significant effects on the trade balance. The combined short-run dynamic effects of the exchange rate, agricultural price and production, and the disposable income jointly explain changes in the trade balance.
La présente étude porte sur les liens à court et à long terme entre la balance commerciale agricole des États-Unis, les agrégats macroéconomiques et les variables agricoles. Nous avons utilisé une analyse de cointégration et un modèle vectoriel à correction d'erreur comprenant des données trimestrielles de 1981 à 2003. Les résultats ont montré que, à long terme, le taux de change, les prix agricoles et le revenu disponible sont faiblement exogènes dans le secteur agricole des États-Unis et qu'ils ont des effets substantiels sur la balance commerciale. Les effets dynamiques à court terme combinés du taux de change, des prix et de la production agricoles ainsi que du revenu disponible expliquent les changements observés dans la balance commerciale.     

Short- and Long-Run Credit Constraints in French Agriculture: A Directional Distance Function Framework Using Expenditure-Constrained Profit Functions

This empirical application investigates the eventual presence of credit constraints using a panel of French farmers. The credit-constrained profit maximization model proposed by Färe, Grosskopf, and Lee is extended in three ways. First, we rephrase the model in terms of directional distance functions to allow duality with the profit function. Second, we model credit constraints in the short-run and investment constraints in the long-run using short- and long-run profit functions. Third, we lag the expenditure constraint one year to account for the separation between planning and production. We find empirical evidence of credit and investment constraints. Financially unconstrained farmers are larger, perform better, and seem to benefit from a virtuous circle where access to financial markets allows better productive choices.