Degree Name

Master of Science (MS)

Semester of Degree Completion

1983

Thesis Director

Roger Darding

Abstract

Six varieties of cool season turfgrasses were exposed to simulated acid rainfall with treatments consisting of a sulfuric acid solution, a nitric acid solution, and a 50-50 mixture of both. Each solution was used to make "acid rain" of pHs 3.0, 2.5, 2.0, and 1.5.

Height measurements showed decreases in growth throughout the experiment for all treatments except the nitric and 50-50 acid treatments at pHs of 2.0 and 1.5, which maintain fairly constant growth. Analysis of nitrate, phosphorous, and potassium levels in the soil indicated heavy leaching of the nitrates and potassium from most soil samples, which probably account for the reduced growth observed. There appeared to be an increase in leaching of potassium from samples recieving the more acidic treatments. Grasses with little decrease in growth showed greater foliar injury than did the stunted plants. Greater foliar injury was also observed at the beginning of the experiment when all the plants were fairly uniform in height. Soil pH showed little change except for the pH 1.5 sulfuric acid treatments, which caused some increase in acidity. There was no correlation between the soil pH and turfgrass height or foliar injury.

A separate, related experiment was conducted to investigate a new chlorophyll extraction procedure reported in the literature for obtaining chlorophyll concentrations expressed as mg chlorophyll per gram dry weight.

Chlorophyll extracts from the injured plants showed a reduction in chlorophyll A, chlorophyll B, and total chlorophyll. Injured plants also showed a decrease in chlorophyll A to B ratios. In addition, higher percentages of chlorophyll were extracted from uninjured tissue than from injured tissue.

Length of storage studies indicated that chlorophyll extracts were stable for at least ten days when stored in the dark.

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