Research Projects

Project at a Glance

Project Status: complete

Title: Effects of present and potential air pollution on important San Joaquin Valley crops: sugar beets

Principal Investigator / Author(s): Brewer, Robert F

Contractor: San Joaquin Valley Agricultural Research and Extension Center, University of California

Contract Number: A6-161-30


Research Program Area: Atmospheric Processes


Abstract:

Sugar beets were grown at Parlier in Fresno County in air from which varying proportions of the existing pollutants had been removed, either by deliberate filtering with activated carbon or passive removal by air handling equipment. Two types of growth chambers were used, one a conventional greenhouse-shaped unit with plastic covered sides and top, and a second experimental unit with plastic walls and open top. All of the chambers were equipped with motor-driven blowers which changed the air twice each minute. In addition to the enclosed, power-ventilated plots there were also outside control plots to provide an estimation of the "chamber effect." Three air treatments were used in the chambers: ambient or non-filtered air, filtered air passed through activated carbon filters, and a mixture consisting of two thirds ambient and one third filtered air.

The primary objectives of this study were to determine the effects, if any, of existing levels of pollution in the central San Joaquin Valley on growth and sugar yields of this extremely important (nearly 50 million dollars annually) agricultural crop and to relate injury symptoms and yield suppression with ozone dose. A secondary objective was simultaneous comparison of closed, greenhouse type exposure chambers with a new open top design.

Growing conditions including light, humidity, temperature, air movement and ozone concentrations were monitored in all of the experimental plots. Excellent plant growth was obtained which assures strong responses, if any, to air pollutants. The most serious problem encountered was a sever invasion of beet armyworm and cabbage loppers in three of the chambers receiving all or part filtered air.

At no time were we able to discern recognizable ozone or PAN injury symptoms on the sugar beet foliage in any of the treatments. When the beets were harvested in early November and the yield data subjected to statistical analysis, none of the growth chamber treatments were statistically different at the .05 confidence level. There was a trend toward increased top weights with filtered air in the open top chambers, but the weights were not statistically different.


 

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