Project at a Glance

Title: Development of a system for evaluating and reporting economic crop losses caused by air pollution in California. I: Quality study

Principal Investigator / Author(s): Oshima, Ronald J.

Contractor: State of California Department of Food and Agriculture

Contract Number: ARB-287

Research Program Area: Economic Analysis

Topic Areas: Agriculture, Costs, Ecosystem Impacts, Impacts


The need for development of accurate air Pollution crop assessment methodology has Increased with public concern over our pressing environmental problems. In order to keep pace with the demands of our increasing population, great efforts have been made to increase agricultural production. Yet, Federal, State, and County agencies have been unable to make an adequate assessment of crop losses caused by air pollutants. The lack of basic information relative to the effects of air pollutants on crops has prevented standardization of assessments and has raised questions as to the accuracy and value of past efforts.

Some of the major problems confronting attempts to assess the extent of air pollution-induced losses have been: 1) controlling the number of variables introduced by the geographical size of agricultural production areas, 2) the lack of sufficient research on agricultural crop varieties to determine loss criteria applicable to field conditions and 3) the enormous expense of establishing and maintaining controlled experiments under field conditions.

Formidable as these and other related problems are, two general approaches to relieve the need for economic crop lose assessments have emerged.

Chamber Studies

Several investigators have, independently and in cooperation, Initiated field studies of selected crops utilizing a variety of sophisticated chambers designed to duplicate field conditions (2, 50 6, 7, 9). These experiments have provided a good deal of useful Information but have not succeeded In developing crop lose criteria applicable to field-grown crops. In each case, the use of "chambers" has significantly influenced the plants within them, either in the selection of diminutive varieties compatible with the size limitations of chambers, or in growth reaction to the chamber's environment. Open top chambers have succeeded in closely approximating ambient climatological conditions, but do not eliminate ambient pollutants in control chambers. Control plants may be affected by the pollutants and the reference for comparing pollution-exposed plants is lost.

Field Observation Assessments

Several surveys have been undertaken utilizing field observations for evaluation of pollution-damaged crops (1, 3, 4,8). The structural design of these studies has varied but all essentially rely on one individual's estimation of leaf damage, its association with yield or quality reductions, and the extent of damage incurred in a particular area. Assessments have varied from individual to individual depending on personal experience and expertise in Identifying pollution injury. The lack of authenticated lose criteria for crops makes standardizatton of assessment impossible, and the accuracy and value of such surveys has been questioned.

Both chamber experiments and field observation assessments have certain advantages and problems inherent In their designs. Field observation assessments are adaptable to large agricultural areas but lack standardization and accuracy. Chamber experiments have much greater accuracy but are financially unfeasible for large geographical areas. Their results are, in most cases, not applicable to field conditions.

This project combines fumigation studies, field plots, and several statistical methods incorporated into an integrated program to develop the needed crop loss assessment methodology. Controlled fumigations were included to determine effects of oxidants and crop loss criteria for specific drops. Field studies throughout the South Coast Air Basin were established to ensure that crop loss criteria developed from fumigations are applicable to field grown crops. Reductions in yield or quantity are correlated with ambient dosages during growth. Should these correlations be significant, further tests could be scheduled to determine the association of yield or quantity reductions with other environmental influence.

This report summarizes results of the first phase of this study dealing with oxidant air pollutant effects on crop quality. It will be followed by phase 2 dealing with the effects of oxidant air pollutants on yield.

For questions regarding this research project, including available data and progress status, contact: Research Division staff at (916) 445-0753

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