Effect of simulated acid rain on growth and yield of Valencia orange, floradade tomato and slash pine in Florida

Direct effects of simulated acidic deposition on vegetation were studied in the laboratory under controlled conditions for three commercially important resources: slash pine, Floradade tomato and Valencia orange. Treatment was similar to convective rain in Florida in ion composition, total volume, frequency and rate of application, intensity and sulfate/nitrate ratio. The surface of the growth medium was covered with plastic during application of the solution. Water and nutrients optimum for growth were provided directly to the growth medium. No visible injury resulted from application of the simulated rain. No effects of pH treatments on vegetative growth of slash pine, orange or tomato were observed. However, fruit yield of tomato and orange differed significantly between plants subjected to different pH treatments. The yield of tomato was lower and that of orange was higher at the lower pH treatments. Calcium and magnesium levels were highest in the foliage of tomato plants receiving the pH 5.5 treatment. No differences in element levels of orange foliage were observed.