Angelos Pagoulatos

Impacts of technological change on factor substitution between energy and other inputs within US agriculture, 1950–79

Abstract Past efforts to estimate elasticities of substitution between inputs both in and out of agriculture have usually made use of a single data set to provide the elasticities between the input pairs, and have led to highly conflicting results, particularly with respect to the substitution between capital or machinery and energy. This study reveals that the elasticity of substitution between a number of input pairs in agriculture can vary by substantial amounts depending on the time period used for the estimation. Energy in agriculture, which was a complement for machinery in the 1950s, was a substitute by the 1970s.

Dynamic Optimal Management of Wind-Erosive Rangelands

A bioeconomic model of livestock production from wind-erosive rangelands is developed and optimized. Equations of motion capture the impact of topsoil stock on forage productivity and the protective effect of forage stock on soil loss from wind erosion. For overgrazed wind-erosive rangelands, a lower discount rate provides incentives for lighter grazing, as does consideration of effect of stocking rates on animal performance. In the case where off-site damages are large, internalizing off-site effects would also encourage lighter grazing and hence promote sustainable production. An illustrative application of the model is also included. Copyright 1997, Oxford University Press.

HUMAN CAPITAL, INCOME, AND ENVIRONMENTAL QUALITY: A STATE-LEVEL ANALYSIS

An empirical analysis reveals that states with more highly educated populations have better environmental conditions, after controlling for income, population density, and industrial composition. The strategy of raising human capital stocks to maintain or improve environmental quality is proposed as a complement, if not an alternative, to direct government intervention, which consists of command and control, market incentives, and moral suasion. Under this approach, general education becomes the control variable that guides economic behavior in a manner consistent with long-term environmental sustainability.

Research in agricultural economics 1919-1990: seventy-two years of change

In this article, we trace the historical development of analytical (quantitative) research techniques used in empirical agricultural economics research by examining the articles in volumes of the Journal of Farm Economics (JFE) and the American Journal of Agricultural Economics (AJAE) from its inception in 1919 to 1990, a total of 72 years. We first determine for each article whether or not empirical results were obtained and then identified the particular quantitative technique employed in order to obtain the results. Then articles are classified with respect to the type of quantitative technique employed. As we reviewed the literature, we attempt to identify studies which marked the first appearance of a particular quantitative method in a JFE or AJAE article. We analyze key trends and illustrate them with a series charts to reveal changes in quantitative techniques used by researchers in writing for the JFE and AJAE. Finally, we explore the implications of these trends for future agricultural economics research.

SOIL EROSION, INTERTEMPORAL PROFIT, AND THE SOIL CONSERVATION DECISION

This study developed an intertemporal profit function to determine optimal conservation adoption strategies under alternative scenarios with respect to crop prices, relative yields, discount rates, and other assumptions. Special emphasis was placed on determining from the analysis when the switchover from conventional to soil-conserving practices should take place. Technological change was incorporated by allowing crop yields to vary over time. Our analysis thus provides a new, more precise measurement of the cumulative net benefit differential. The optimal period for switchover from conventional to soil-conservating practices was found to vary depending on the assumptions made about corn prices and discount rates. Empirical results were based on an erosion damage function (EDF) for Western Kentucky corn production.

Estimating Linear Probability Functions: A Comparison of Approaches

A linear probability function permits the estimation of the probability of the occurrence or non-occurrence of a discrete event. Nerlove and Press (p. 3–9) outline several statistical problems that arise if such a function is estimated via OLS. In particular, heteroskedasticity inherent in such a regression model leads to inefficient estimates of parameters (Amemiya 1973, Horn and Horn). Moreover, without restrictions on the conventional OLS model, probability estimates lying outside the unit (0–1) interval are possible (Nerlove and Press). Goldberger and Kmenta suggest two approaches for alleviating the heteroskedasticity problems inherent in the OLS regression model. Logit analysis will also alleviate heteroskedasticity problems and ensure that estimated probabilities will lie within the unit interval (Amemiya 1974, Hauck and Donner, Hill and Kau, Horn and Horn, Horn, Horn, and Duncan, Theil 1970).

An economic analysis of wind erosion control in the inner Mongolia Plateau, China

This study investigates specific changes in farming practices aimed at reducing wind erosion from cropland in the inner Mongolia Plateau, China, and incorporates the value of dust reduction in downwind regions into a formal cost-benefit framework, both from the farmers perspective and societys perspective. The result shows the need for incorporating off-site damages from wind erosion in policy analyses. Measurement of the off-site damages is difficult, especially in a mixed economy such as Chinas. A conservative estimate was obtained by benefit transfer from a non-market valuation study conducted in a developed country. This conservative estimate was large enough to be decisive in the policy analysis.

Computer Graphics: An Educational Tool in Production Economics

Students usually have difficulty in understanding the nature of surfaces generated by two-input production functions. Isoquant maps in two dimensions are easy to draw, and wooden or plastic models have sometimes been used by instructors to help students discover the relationship between an isoquant map and the resultant production surface. However, these models are difficult to build and expensive. Moreover, the exact mathematical specification of the production function underlying the plastic or wooden model is usually ambiguous. But the most serious disadvantage of such a model is that even if a mathematical specification of the production function underlying the model is known, it is impossible with a single model for the instructor to change the underlying function (and hence the isoquant map) so that the student might observe the resulting impacts on the surface of the function. Computer graphics can be used as an educational tool for helping students better learn production economics concepts. A plotter linked to a computer is used to generate three-dimensional illustrations of two-input agricultural production functions.l Moreover, production economics problems often require the maximization or minimization of a function, and computer graphics can be used to develop an understanding of the mathematical conditions necessary and sufficient for a maximum or minimum. This use is particularly important to supplement material in beginning graduate level production economics classes.

Energy Problems and Alternatives: Implications for the South

Though agriculture in the United States has been looked upon as being technically efficient in terms of output per unit of labor, it is not nearly as efficient in terms of output per unit of liquid fuels consumed (Debertin, Pagoulatos, and Boadu; Pagoulatos and Timmons). In this article, we examine the potential for substituting other inputs for liquid fuels in the agricultural production process. Studies of elasticities of substitution between energy and other inputs are reviewed. On the basis of these studies, we suggest possibilities for using other inputs instead of liquid fuels in agriculture. We present recent research results relating fuel use to tractor prices and horsepower. We compare Kentucky counties in terms of their energy use in relation to their mix of agricultural enterprises and mechanization levels. Finally, we speculate on the potential impacts of significant increases in real fuel prices on the major agricultural enterprises in the South.

OPTIMAL MANAGEMENT STRATEGIES FOR ALFALFA PRODUCTION WITHIN A TOTAL FARM PLAN

This paper examines the impacts of alternative management strategies for the production of alfalfa within the context of a total farm plan. A linear programming model is used to represent a 600-acre farm which can grow either grain crops or alfalfa. Alfalfa production competes with the grain crops for available land, labor, machinery, and field time over a calendar of tillage, plating, cutting, spraying, and harvesting activities. The profitability of an acre of alfalfa and the contribution of alfalfa to net returns for the farm varies quite widely depending on the particular alfalfa management strategy selected.