Richard K. Perrin

Net energy of cellulosic ethanol from switchgrass

Perennial herbaceous plants such as switchgrass (Panicum virgatum L.) are being evaluated as cellulosic bioenergy crops. Two major concerns have been the net energy efficiency and economic feasibility of switchgrass and similar crops. All previous energy analyses have been based on data from research plots (<5 m2) and estimated inputs. We managed switchgrass as a biomass energy crop in field trials of 3–9 ha (1 ha = 10,000 m2) on marginal cropland on 10 farms across a wide precipitation and temperature gradient in the midcontinental U.S. to determine net energy and economic costs based on known farm inputs and harvested yields. In this report, we summarize the agricultural energy input costs, biomass yield, estimated ethanol output, greenhouse gas emissions, and net energy results. Annual biomass yields of established fields averaged 5.2 -11.1 Mg·ha−1 with a resulting average estimated net energy yield (NEY) of 60 GJ·ha−1·y−1. Switchgrass produced 540% more renewable than nonrenewable energy consumed. Switchgrass monocultures managed for high yield produced 93% more biomass yield and an equivalent estimated NEY than previous estimates from human-made prairies that received low agricultural inputs. Estimated average greenhouse gas (GHG) emissions from cellulosic ethanol derived from switchgrass were 94% lower than estimated GHG from gasoline. This is a baseline study that represents the genetic material and agronomic technology available for switchgrass production in 2000 and 2001, when the fields were planted. Improved genetics and agronomics may further enhance energy sustainability and biofuel yield of switchgrass.

LDC agriculture: Nonparametric Malmquist productivity indexes

Abstract This paper examines changes in agricultural productivity in 18 developing countries over the period 1961–1985. We use the nonparametric, output-based Malmquist index to examine whether the results from such an approach confirm results from other methods that have indicated declining agricultural productivity in less developed countries (LDCs). The results confirm previous findings, indicating that at least half of these countries have experienced productivity declines in agriculture. We also found that those countries that tax agriculture most heavily had the most negative rates of productivity change.

Prices and Productivity in Agriculture

Developing countries often tax agriculture heavily, a practice that might affect the productivity as well as the quantity of resources allocated to agriculture. A variable-coefficient cross-country agricultural production function is estimated, with past price expectations among the determinants of the production coefficients. Productivitys responsiveness to the expectations implies that, had these developing economies eliminated price interventions, agricultural productivity would have increased by and average of 25 percent.

Agricultural productivity in developing countries

This paper examines changes in agricultural productivity in 18 developing countries over the period 1961-1985. We use a nonparametric, output-based Malmquist index and a parametric variable coefficients Cobb-Douglas production function to examine, whether our estimates confirm results from other studies that have indicated declining agricultural productivity in LDCs. The results confirm previous findings, indicating that at least half of these countries have experienced productivity declines in agriculture.

Asset Replacement Principles

Using a general model of asset replacement, a replacement principle is derived which applies to both appreciating assets such as forests and depreciating assets such as equipment. The resulting replacement criterion provides a definition of opportunity costs appropriate for the replacement decision. The theory is presented graphically for the continuous time case, and two discrete-time examples are considered. Theoretical implications of changing discount rates and market forces are considered as they affect replacement policies.

THE THEORY AND MEASUREMENT OF PRODUCER RESPONSE UNDER QUOTAS

Tobin and Houthakkers (1950-51) work on consumer behavior under quantity rationing has been extended by many authors, especially through the use of duality theory. This paper uses duality theory to extend the work on demand theory under rationing to the case of producer behavior under quotas. These results permit estimation of otherwise unobservable market supply and demand structures. The structure of the farm economy operating under a tobacco quota system is estimated, and the theory is utilized to infer that the supply elasticity of tobacco would be about 7.0 if the quotas were removed. Estimates such as this are not normally attainable without the theory outlined here, even though they are essential for the evaluation of policy changes.

Impediments to Technical Progress on Small versus Large Farms

During the past four years, Centro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT) has been associated with a number of farm-level studies of the adoption of new wheat and maize varieties and fertilizer use. Most of these studies have now been published, and it is our purpose here to summarize some of the findings with respect to impediments to farmer adoption of new varieties. Farm-to-farm differences in the date of adoption or the extent of adoption of new technology might be explained by a number of considerations. The studies reviewed here considered farm-to-farm differences in the cost of acquiring and processing information, differences in the physical productivity of the new technology, differences in incentives due to tenure arrangements, differences in the cost of inputs, differences in prices received for the product, differential aversion to risk among farmers, and scale effects associated with farm or enterprise size. Policies to stimulate more rapid or more extensive adoption will vary in their success depending upon which of these factors are the most important in limiting the rate and extent of adoption. Of particular relevance is the extent to which small farmers lag behind large farmers in adoption and which of the above factors might account for that lag. The studies were directed toward factors

The Value of Information and the Value of Theoretical Models in Crop Response Research

The concepts of the value of information and the value of alternative models are developed and applied to corn response research in Brazil. Soil test information was worth as much as

Argentine Agricultural Policy in a Multiple-Input, Multiple-Output Framework

30 per hectare and the response model employed was worth up to

The Impact of Component Pricing of Soybeans and Milk

23 per hectare, but two soil classification models had negative values.