COMBINATIONS OF BUFFER-STOCKS AND BUFFER-FUNDS FOR WOOL PRICE STABILISATION IN AUSTRALIA*

In this paper a preliminary analysis is presented of a combined buffer-fund and buffer-stock as an alternative to a pure buffer-fund or a pure buffer stock for stabilising wool prices. The alternatives analysed are designed so that each provides the same prices to producers as did the Reserve Price Scheme over the period of analysis. Least-cost combinations of policy instruments are derived. The results show that there is considerable potential for cost savings to be made by combining buffer-fund and buffer-stock instruments.     

WOOL IN 1980*

Since the introduction of a reserve price scheme in 1970, the interest in wool marketing previously shown by agricultural economists has not been maintained outside the public service and the wool industry itself. Nor is the subject as divisive amongst wool growers with, in general, 'orderly marketing' now acceptable to all factions of wool growers. The history of wool marketing discussion in Australia is reviewed and some reasons for this changing climate of opinion are discussed. An attempt is made to assess the actual performance of the buffer stock scheme in the light of the academic literature of the 1960s.     

OPTIMAL FEEDING POLICIES FOR BROILER PRODUCTION: AN APPLICATION OF DYNAMIC PROGRAMMING*

The determination of an optimal feeding and selling strategy for broiler production given a space constraint is formulated as a dynamic programming problem. Production equations derived from trial data are used to obtain an optimal sequence of rations in which energy density changes through time. The stability of the plan is explored and the implications of the results for production research and commercial practice are considered.     

THE DETERMINATION OF OPTIMAL RATIONS FOR PIGS FED SEPARATED MILK AND GRAIN*

This paper demonstrates a procedure for determining economically optimal rations which avoids problems that arise in conventional analysis of experimental results. It consists of maximising a suitably constrained profit per unit time objective function, itself formed from functions obtained from pig fattening experiments under special Australian conditions. The relevant functions-for consumption of milk and wheat, time to slaughter and percentage lean meatare first demonstrated, followed by a brief discussion of results obtained. Specifcally, it is noted that optimal diets differ according to whether the criterion adopted is profit per pig or profit per pig per week, that dairy farmers fattening pigs should feed substantial quantities of grain, and that the optimal diets are very stable to changing prices. More generally, the procedure avoids the statistical difficulties of conventional analysis of experiments arising from the estimation of weight-gain functions based on actual quantities of food consumed.     

WOOL PRICE STABILISATION AND PROFIT RISK FOR WOOL USERS

It has often been suggested that more stable wool prices would lead to an outward shift in the long-run demand for wool. To assess this claim it is necessary to examine different sources of risk and instability in wool prices and their impact on the risk borne by wool users. A model is presented in which the input and output decisions of a wool processor are related to interactions between the wool and yarn markets. It is concluded that, if fluctuations in final demand or exchange rates are the major sources of instability, the long-run effect of stabilising prices is to increase the risk faced by wool users and reduce that faced by wool growers.     

THE EFFECTS OF FLEXIBLE EXCHANGE RATES ON AUSTRALIAN WOOL PRICES*

The implication of price stabilisation under a volatile exchange rate is an increasingly volatile price denominated in a foreign currency. Time series analysis is used to model the relationship between exports, prices and AWC stocks. This model is used to assess the distribution of the impact of exchange rate shocks on prices denominated in local and foreign currencies. It is found that the AWC has significantly reduced the impact of exchange rate shocks on domestic prices.     

THE INVENTORY SCHEME FOR AUSTRALIAN WOOL

A model put forward by the Australian Wool Corporation to simulate the behaviour of the wool market under an inventory scheme is described. Some deficiencies in the model are pointed out and suggestions are made for alterations to improve the model's performance.     

THE IMPACT OF FARM AND PROCESSING RESEARCH ON THE AUSTRALIAN WOOL INDUSTRY*

An equilibrium displacement model of the world wool top industry is used to estimate the returns to the Australian wool industry from productivity improvements in farm production, in top making and in textile manufacturing. The returns to the industry from these different types of research and development are sensitive to the extent of substitution possibilities between Australian wool and other inputs used by the wool processing and textile industries but it appears that research resources have to be much more efficient in off-farm activities for the Australian wool industry to receive benefits similar to those from farm research activities.     

MEASURING CASH FLOWS BY FARM TYPE*

Data from the records of 68 Ontario farmers indicate significant variarion in levels and seasonality of cash flows among several major types of farms. Hence farm type may be a useful classification for data gathering and analysis of financial position. Major differences in level of borrowing between farm types can be attributed to the relative use of agribusiness credit and to seasonal fluctuations in net cash receipts. Des données prises des enregistrements de 68 exploitants ontariens indiquent ?exploitation parmi plusiers types principals de fermes. Done, le type ?exploitation peut être une classification utile pour la collection de données el pour ?analyse de la position financiére. Des differences importantes de niveau ?emprunt parmi des types ?exploitation peut étre attribuées à?utilisation relative de “crédit agribusiness” ainsi qu'aux fluctuations saisonières des recettes comptants nets.     

FUTURES PRICES AS FORECASTS OF COMMODITY SPOT PRICES: LIVE CATTLE AND WOOL*

In this paper the foundations on which the predictive interpretation of futures prices rests are discussed, and possible reasons for the differential predictive performance of futures prices as between different commodity markets examined. The predictive performances of futures, and spot prices themselves, are tested empirically, using Australian data for wool (a continuous inventory commodity) and finished live beef cattle (virtually a non-storable commodity), by means of instrumental variables estimation.     

我国粮食综合运输费用与最优物流路径研究

北方是中华民族农耕文明的发源地,但唐宋以来,随着长江流域和珠江流域逐渐被开发,中国的经济重心逐步南移,至南宋时,中国的经济重心完成了南移的过程。元朝为保证大都及北方的粮食供给,开辟了海运和漕运路线,历经明、清、民国和改革开放初期,形成了数百年的南粮北调局面。上世纪80年代,由于东北和西北地区荒地资源的开发和华北平原农业生产的发展,中国实现了由南粮北调向北粮     

AN OPTIMAL-CONTROL APPROACH TO STABILISING AUSTRALIAN WOOL PRICES*

In this paper, some aspects of the application of optimal-control techniques to wool industry price stabilisation are considered. It is not intended to provide a blueprint for the immediate adoption of optimal-control techniques in the management of wool price stablisation. Rather, the contribution is to the developmental and evaluative process involved in considering these techniques. A new econometric model of wool price and supply is also presented, since none of the existing models satisfied the requirements of the study.     

A NOTE ON HIDDEN GAINS AND LOSSES OF BUFFER STOCK SCHEMES FOR WOOL

This note is concerned with one aspect of the methodology for examining the gains and losses of a buffer stock scheme for wool. It is shown that it is incorrect to debit interest due on capital tied up in stocks of wool without, at the same time, crediting a portion of this to the grower. The errors that can occur in calculations that do not take account of the charged time distribution of growers' receipts are demonstrated.     

TOWARD AN OPTIMAL POLICY OF SUPPLY CONTROL AND INCOME IMPROVEMENT*

This analysis provides a theoretical framework for a tax policy to reduce farm output, stabilize prices, and improve farm income. It is a policy that does not require production or marketing quotas, support prices, government subsidies, or commodity storage. It is proposed as an optimal supply-restraining, income-improving policy in terms of administrative economy and absence of treasury payments. The mechanism could be applied by the farmer's own marketing board or by government. It leaves freedom of decision (except for the payment of the tax that later increases income) to farmers. It eliminates restraints on intraregional efficiency and intercommodity barriers inherent in traditional supply control programs such as the administration of marketing quotas. The revenues from the tax collection, after expenses were paid, could be used in various ways to improve welfare and income distribution within the sector, thus improving the level of living of all farmers individually and as a group Cette analyse foumil une structure théorique d“un système ?impôts destinéà ralentir la production agricole, à en stabiliser le prix et à augmenter son revenu. C'est un système qui n'exige ni quotité (soit de production, soil de marché), ni support de prix, ni subvention fédérate, ni entrepôt de surproduction. On propose ce système comme le meilleur moyen de réaliser les buts ci-dessus mentionés, en dépit des économies administrates et du manque de subvention du Ministère des Finances. Ce procédé peut être mis en pratique, soit par le gouvernement, soit par la commission mercantile de ?exploitani agricole même, à qui reste seul la liberté de décision (sauf quand il s'agil du paiement de ?impôt qui sen plus lard à?ac-croissement des revenus.) Ce sont des restrictions à la compétence intrarégionale qui sont éliminées ainsi que des obstacles entre produils de consommation: obstacles particuliers aux plans traditionnels de contrôle de production, lets que ?institution de quotités de marché. Les revenus des impôts, les dépenses réglées, peuvent s'utiliser de plusieurs moyens à contribuer au bien-être général et à accroitre les revenus dans la région mème, améliorant, de cette façon, la condition du fermier: celle de ?individu ainsi que la condition collective du groupe     

A STOCHASTIC MODEL FOR THE OPTIMAL REPLACEMENT OF RUBBER TREES

Recognizing the lack of realism in optimal replacement analyses that assume constant prices and yield patterns over time, a stochastic model appropriate to rubber production is developed. Data drawn from Peninsular Malaysia are used to implement the model. The results suggest that efforts should be directed towards establishing bench mark maximum annuities as guides to more economic replanting decisions rather than emphasizing earlier replanting per se. The significance of price stabilization policies also becomes evident.     

THE OPTIMAL CHOICE OF A VARIETY OF A SPECIES FOR VARIABLE ENVIRONMENTAL CONDITIONS

When yields of a variety are a non-linear function of a relevant environmental condition, variability of this condition affects the average level of yields, and may favour one variety in comparison to another. When the yield function is strictly concave (exhibits diminishing marginal yield as a function of the environmental condition), heightened environmental variability increases the likelihood of the variety with the smallest change in marginal yield, the more tolerant one, maximising yield on average. However, if the yield function is strictly convex (increasing marginal yields are the case) increased environmental variability raises the likelihood of the variety with the greatest change in marginal yield, the less tolerant one, maximising yields on average. Examples are given, and simple rules are stated for choosing the variety that maximises average yields when yield functions are quadratic. The analysis can be adapted to decision-making in which average profit or expected utility, rather than average yield, is to be maximised.     

SOCIAL COSTS OF REGULATION OF PRIMARY INDUSTRY: AN APPLICATION TO ANIMAL WELFARE REGULATION OF THE VICTORIAN PIG INDUSTRY*

The effects of state government regulation of primary industry are modelled. An analytical framework is presented for estimating the costs of regulation in terms of changes in economic surplus. The model permits trade between regions of the total market. An illustrative application of the framework is applied to proposed animal welfare regulation of the Victorian pig industry. Some regulations that may provide large gains with regard to the welfare of farm animals involve only small social costs compared to the gross value of production of the industry. Conversely, other regulations that potentially confer only small gains in animal welfare impose large social costs. The distribution of these costs is important. In general, consumers lose, as do some producers. Other producers gain. In some cases, producers in aggregate gain from regulation. Major beneficiaries, such as advocates of animal welfare regulations, are likely to bear little of the cost of regulation.     

AN OPTIMAL MANAGEMENT MODEL FOR INTENSIVE AQUACULTURE — AN APPLICATION IN ATLANTIC SALMON*

In this paper the optimal management strategy for intensive aquaculture is viewed in terms of a combined strategy of releasing the optimal number of recruits and harvesting those recruits at the optimal harvesting time. A model which can be used to determine the optimal management strategy is developed. In the model the optimal harvesting model documented by Bjorndahl (1988, 1990) in which harvesting and feed costs are considered, is extended by including release costs and how they influence the optimal number of recruits. The model forms the basis for an empirical analysis in which the optimal management strategy for a yearclass of Atlantic salmon farmed in Australia during 1989-91 is considered.     

THE NATURE OF PRICE MOVEMENTS DURING SINGLE SALES FOR THREE INDIVIDUAL WOOL TYPES SOLD IN SYDNEY

Price series for three wool types sold in Sydney are tested for the presence of serial correlation using the von Neuman ratio. The results indicate that it is unusual to find significant serial correlation between prices during a single sale. These results have implications for the use of various statistical techniques in wool marketing research and for buying tactics in the market generally.