POPULATION DYNAMICS AND MILK SUPPLY RESPONSE IN THE US LAKE STATES

This paper develops a dynamic model of a dairy cow population and of milk supply response. When applied to the US Lake States, the model provides evidence against the Nerlovian model. It suggests that the pattern of dynamic effects of prices on cow numbers varies for different prices. The estimated dynamic supply elasticities provide some useful information on the nature of dairy production adjustments. For example, the response of milk supply to market prices is found to be very inelastic in the short run. It takes at least 7 years of sustained change to obtain an elastic response to milk price. Also, feed price and slaughter cow price are found to have smaller effects on dairy supply than milk price, but larger effects than risk, hay price or capital cost.     

International Supply Response

Long-run aggregate agricultural supply elasticities obtained from conventional supply functions fitted to time series data tend to be relatively inelastic in the range of 0.1 to 0.4. I argue that these estimates substantially understate the true long-run supply response in agriculture. Because of the lack of international input price data, implicit output/input price ratios are estimated from a production function assuming profit maximization. The estimation of an aggregate supply function utilizing these price ratios yields long run aggregate supply elasticities in the range of 0.90 to 1.19. These figures are substantially larger than those obtained from conventional supply functions fitted to time series data, but correspond closely to estimates reported in an earlier crosscountry study that used different price data for different points in time. The results imply that policies which distort domestic and/or world market prices of agricultural products cause greater output distortions in both the DCs and LDCs than are predicted by the small supply elasticities obtained from conventional supply estimation.     

Decompositions of corn price effects: implications for feed grain demand and livestock supply

This article examines how corn prices affect the demand for feed grains and the supply of livestock outputs. The differential approach to the theory of the multiproduct firm is employed to examine ex ante decisions about feed grain demand and livestock supply. The estimation results suggest that livestock producers have little flexibility in adjusting the demand for corn in response to an increase in corn prices. The substitutable relationship between corn and distillers’ grains contributes to alleviating pressures on feed costs in response to high corn prices. In addition, the estimation results highlight that the composition of livestock supply can be altered by changes in livestock prices. On the basis of the estimated elasticities, the decompositions of profit‐maximizing input demand are conducted to examine the effects of changes in corn prices on feed grain demand and livestock supply. The decomposition results reveal that an increase in corn prices reduces corn demand but raises the demand for distillers’ grains mainly due to the substitution effects of corn price changes. The decomposition results also show that an increase in the price of corn reduces cattle supply but raises the supply of chicken and pork due to the output relationships in supply.     

Agricultural Supply Response: A Survey

This paper surveys the literature on agricultural supply response to prices in developing countries. Empirical estimates of elasticities depend both on the methodology adopted and on country-specific factors relating to technology, economic structure and macro constraints. The paper seeks to establish some general conclusions on supply responsiveness within these limitations. Supply response to output prices at the aggregate and at the crop levels is considered first. Crop-specific acreage elasticities range between zero and 0.8 in the short run while long-run elasticities tend to be higher — between 0.3 and 1.2. Yield elasticities are smaller and less stable than acreage elasticities. Clearly, inter-crop pricing can be relied upon to effect shifts in the commodity composition of agricultural output. Evidence also suggests that supply elasticities vary systematically with such factors as price and yield risks, multiple-cropping, the importance of the crop, farm incomes, farm size, tenancy and literacy. The most controversial and important aspect of supply response is the effect on aggregate agricultural output of agriculture's terms of trade. Conventional time-series estimates range from 0.1 to 0.3. A major cross-country study reports an aggregate elasticity as high as 1.66. It is argued that cross-country estimates are apt to exaggerate aggregate responsiveness while time-series studies underestimate it somewhat. For LDCs, a tentative range of 0.4 to 0.5 seems plausible. Hence, the distributive effects of the terms of trade are likely to be more significant than the allocative effects. Asian evidence shows that only a third of the inter-country differences in fertilizer use can be attributed to fertilizer price policies. Provided new technologies and infrastructure are in place, fertilizer subsidies can help in technology diffusion and in overcoming credit constraints. The choice between price supports and input subsidies will depend on a variety of country- or situation-specific factors. Nevertheless, a significant general factor favoring price supports is that they can more easily be coupled with price stabilization goals than input subsidies. Though sparse, the available evidence on the response of marketed surplus suggests that price policy is not a reliable instrument for regulating inter-sectoral trade.     

CANADIAN WHEAT ACREAGE RESPONSE*

In spite of the criticisms which have been levied against statistical estimation of supply response, it is used in this study to determine the factors causing yearly fluctuations in Canadian wheat acreage. The estimates are derived from 1947–1966 time series data. In formulating price expectations, both the traditional and distributed lag models are used.
It was found that wheat acreage response is not a random process. From a statistical standpoint, wheat and flax prices, wheat stocks on farms, and export sales did affect farmers' wheat acreage decisions. Among the elasticities computed, those for wheat prices were the largest but generally less than one. Barley prices, rainfall prior to seeding, and cattle prices were also considered but did not appear to have a serious influence on wheat acreage.     

PRICISM v. STRUCTURALISM IN SUB-SAHARAN AFRICAN AGRICULTURE

A re-examination of data frequently used to support the notion of price discrimination against agriculture in Sub-Saharan Africa suggests that the extent of agricultural taxation has been overstated. In addition, a review of the evidence on the aggregate agricultural supply response to price indicates that elasticities are low, with the most plausible estimates lying in the range 0.2–0.4. Eight structural constraints explaining the poor supply response, to which Sub-Saharan Africa is particularly prone, are identified. Further evidence is presented to show that output responds more significantly to structural factors than to price, and that investment in rural infrastructure will bring about an improved response to price. Capital constraints limit price-induced private investment, so that public sector led investment in new technology and rural infrastructure would appear to be the single most important strategy for reversing the decline in African agriculture.     

Estimating the supply response of cotton and cereal crops in smallholder production systems: recent evidence from Mali

Cotton is one of the most important crops in West Africa and is a major catalyst of economic development in rural areas, but the sector has suffered from a decline in the world cotton price after 1999. This article exploits an unusual data set following 82 farmers over 14 years, from 1994 through 2007, to estimate a Nerlovian supply response model for cotton, maize, sorghum, and millet in long-term rotation. The resulting system of equations is estimated with two-stage least squares (2SLS), showing that this sample of Malian cotton producers have responded to prices in a relatively inelastic manner, with supply elasticities only about one-half of those estimated for producers in developed countries. Policy reforms could help producers respond more easily to prices changes, as well as to raise average productivity levels.     

Price elasticity of water allocations demand in the Goulburn–Murray Irrigation District*

Bid prices for the demand and supply of water allocations between 2001 and 2007, and average monthly prices paid for water allocations from 1997 to 2007 in the Goulburn–Murray Irrigation District are analysed to estimate price elasticities. Based on bid prices, the price elasticity of demand for water allocations appears highly elastic, with elasticities strongly influenced by the season and drought. The price elasticity of supply for water allocations is also elastic, albeit less elastic than demand. Using actual prices paid, water demand is negatively related to price and is inelastic, and appears to be most influenced by demand the previous month, drought and seasonality factors.     

A Review of International Agricultural Supply Response

Existine literature has orovided a wide ranee of estimates for supply elasticities. This study reviews agricultural supply response in developed and developing countries. The main obiective is to provide an understanding of the causal factors accounthg for the diversity of estimates. It is discussed that the estimated elasticities vary depending on the methodology used, the time period the cover, the definition of price variable, and the type of data utilized: The various methodologies employed to estimate supply elasticities are discussed. Finally, some conclusions are derived which are supported by the theory and the weight of the evidence.     

食品安全丑闻报道与产销价格传导——基于中国猪肉市场的经验研究

本文利用主流媒体对猪肉质量安全事件的新闻报道构造食品安全丑闻报道指数,首次从媒体报道视角分析食品安全丑闻对中国猪肉供应链产销价格传导的影响。平滑转换误差修正模型检验结果表明:(1)食品安全丑闻报道是决定产销价格传导关系的门槛变量,当食品安全丑闻报道指数处于门槛值以内时,产销价格传导表现为线性关系,超出门槛值以后,则表现为非线性关系,但更多时候表现为非线性关系;(2)食品安全丑闻报道对产销价格具有非对称冲击效应,生猪价格比猪肉价格对冲击的反应程度更大、持续时间更长。这种非对称冲击效应不仅会打破产销价格波动的固有规律,也会加剧供应链上福利分配不均衡,处于弱势地位的养殖户更容易遭受福利损失。进一步采用向量自回归模型进行脉冲响应分析,结果仍然支持上述结论。     

On the nature and magnitude of cost economies in hog production

In this article, we assess the impact of farm size on production cost and evaluate the marginal costs and margins by considering that input prices may change with the scale of production. By using French hog farm data, we estimate a system of equations including a feed price function, input demand functions, and an output supply function based on a technology approximated by a combined generalized Leontief‐Quadratic form. Our results suggest that the marginal costs are over‐estimated when the adjustment of the feed unit prices to a change in farm size is not controlled for. More specifically, the cost economies for large farms (enjoying the highest profits) arise primarily from lower feed prices, with technological scale economies having little impact. In contrast, farms with no hired labor exhibit technological scale economies and reach higher price‐cost margins compared to larger farms.     

SUPPLY RESPONSE OF AUSTRALIAN WHEAT GROWERS

Alternative specifications of models of the supply response of Australian wheat growers and their economic implications are considered in terms of the existence and nature of production lags, and the choice between expected prices and expected gross returns as the preferred explanator of producers' response to changing economic conditions. The analysis indicates that there are lags which are due primarily to the difficulties and costs of rapid adjustment rather than to the time required to revise expectations. The statistical results were similar for the alternative specifications of gross margins and prices as the economic decision variables. However, the price elasticities derived using the gross margins specification were about a third of those using the prices specification. The gross margins specification yielded additional information in the form of yield and input cost elasticities.     

Energy substitutability in transition agriculture: estimates and implications for Hungary

Subsidised energy prices in pre‐transition Hungary had led to excessive energy intensity in the agricultural sector. Transition has resulted in steep input price increases. In this study, Allen and Morishima elasticities of substitution are estimated to study the effects of these price changes on energy use, chemical input use, capital formation and employment. Panel data methods, Generalised Method of Moments (GMM) and instrument exogeneity tests are used to specify and estimate technology and substitution elasticities. Results indicate that indirect price policy may be effective in controlling energy consumption. The sustained increases in energy and chemical input prices have worked together to restrict energy and chemical input use, and the substitutability between energy, capital and labour has prevented the capital shrinkage and agricultural unemployment situations from being worse. The Hungarian push towards lower energy intensity may be best pursued through sustained energy price increases rather than capital subsidies.     

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.     

SUPPLY RESPONSE OF UPLAND RICE IN OGUN STATE OF NIGERIA: A PRODUCER PANEL APPROACH

Several reasons have been proposed to explain the unexpectedly low supply elasticities often found for food crops. This study is unusual in using a farmers' panel approach. This enables a distinction to be made between four different measures of response: realised output, planted hectarage, planned hectarage and ‘hypothetical’ hectarage. The results indicate that the own-price elasticities of supply are significantly positive. Planned, planted and realised responses are quite close, but are less than the hypothetical responses. The hypothetical elasticities are smaller for price falls than for price increases and they become lower as the harvesting period passes, suggesting contraction of supply of a crop when its price falls and asymmetric response among small-scale farmers.     

Supply side constraints in the Israeli housing market—The impact of state owned land

House prices in Israel have risen since 2008 by as much as 98%. Much of this increase is attributed to low levels of housing supply and housing supply elasticities. In Israel land is frequently owned by the state. This results in heavy government involvement in the housing market through the control of land supply via land tenders. This paper estimates the impact of state owned land on the Israeli housing market focusing on these unusual conditions of land supply. A model for the creation of new housing units is proposed. This incorporates land tenders, enabling the estimation of housing supply dynamics with an accurate measure of public land supply. The model is tested using regional panel data which facilitates the dynamic estimation of national and local supply elasticities and regional spillovers. The paper uses novel data sources resulting in a panel of 45 spatial units over a span of 11 years (2002–2012). Due to the nonstationary nature of the data, spatial panel cointegration methods are used. The empirical results yield estimates of housing supply price elasticities and elasticities with respect to land supply. Results show that housing supply is positively impacted by governmental decisions but the impact is low. Supply elasticity with regard to government land tenders stands at around 0.05 over the short run and 0.08 over the long run. Government policy of offering land in low demand areas and fixing minimum-price tendering does not seem to affect housing supply. Policy implications point to the need for more sensitive management of the delicate balance between public and private source of land in order to mitigate the excesses of demand shocks.     

On the Use of Price Ratio in Aggregate Supply Response: Some Evidence from the Poultry Industry

The specification of supply/demand relationships has received considerable attention in agricultural economics (Heien 1977). Economic theory has helped provide a basis for the specification of such relationships, one of its contributions being the proposition that prices should be interpreted only in relative terms. This has had a profound influence on model building in agricultural economics, leading a number of researchers to avoid the use of absolute prices in economic analysis. For this reason, numerous market models of the agricultural economy use price ratios as explanatory variables (e.g., Chen; Chen et al.; Heien, 1976; Gerra; Kulshreshtha and Wilson; Rahn; Talpaz; Morzuck et al.; Houck and Gallagher; Wilson et al.); these examples suggest that the use of such ratios is fairly widespread in econometric modeling of the crop and livestock sectors. One of the best examples of price ratios is the "feed cost to price" ratio commonly used in the analysis of livestock supply response. Indeed, since feed cost constitutes a major part of the total production cost in livestock activities, the "feed cost to price" ratio is often considered a proxy for profitability. For this reason, data on such ratios are regularly published for various livestock activities (e.g., USD A). Also, "feed cost to price" ratios are often employed in the specification of models of livestock supply response, (e.g., Chen; Chen et al.; Heien 1976; Gerra; Kulshreshtha and Wilson; Rahn; Talpaz). However, not all models of aggregate supply response follow this approach. For example, Freebairn and Rausser, and Arzac and Wilkinson, use prices as separate variables rather than in ratio forms in their models. In particular, they do not employ price ratios in their livestock and crop supply equations. The existence of these different approaches raises questions about the appropriateness of the use of price ratios in the modeling of aggregate supply.     

Price supply response of vegetable growers in the Sultanate of Oman

Information on supply price elasticities has been acknowledged as being very important for decision makers at the macro and micro levels. This paper presents an empirical investigation of vegetable growers' responses to prices in Oman. It develops a single supply response function incorporating adaptive expectation model for prices. Results indicate that growers adjust relatively fast to changes in expected prices. However, these adjustments tire rather low for some crop in the short-and long-run. Growers' production decisions have also shown a significant response to prices of other products competing for farm space and other production resources. These results will support efforts aimed at market development and crop enhancement programs.     

Estimation of dynamic maize supply response in Zambia

Increased attention on government pricing policies among African nations leads directly to a need for information about producer responses to price adjustments. This is especially true in the case of Zambian maize production. Maize is the most important crop grown in Zambia. It accounts for more than 80% of the value of marketed food crops, is heavily relied on for subsistence consumption, and is a staple food in the diet of all Zambian citizens. This paper analyzes the aggregate price response of maize supply in Zambia using a dynamic regression analysis. As a result, short, intermediate and long-run multipliers/elasticities are measured which can be used to analyze the effect of future price policy changes. It was found that a second-order rational distributed lag model best fits the available data. Estimates of short-run elasticities of supply for maize and fertilizer prices are 0.54 and –0.48, respectively. The corresponding estimated long-run elasticities are 1.57 and – 1.44.     

Estimation of Area Elasticities from a Standard Profit Function

This article demonstrates that both crop area and output elasticities can be calculated from a profit function. A Chambers/Just profit function (which includes land allocations as quasi-fixed factors) is used to derive shadow price equations for each crop area allocation. Jointly solving these shadow price equations for crop area makes it possible to calculate individual crop area elasticities. A profit function is specified to represent agricultural producers in the state of Iowa. Shadow price equations are jointly estimated with output supply and input demand equations. From these estimated equations, we derive the individual crop area response and output response to a change in prices.