Response of Maryland Tobacco to Saline Aerosol Emissions From Brackish Water Cooling Towers1
- Charles L. Mulchi and
- J. A. Armbruster2
Field studies were conducted on Maryland tobacco (Nicotiana tabacum L.) for 8 weeks during each summer from 1973 to 1977, to acquire information on the response of tobacco to simulated saline aerosol deposition from brackish water cooling towers. The studies involved two sources of salts (NaCl and brackish water from the Unit 3 cooling tower at Chalk Point, Md.), and various salt deposition rates (0.97 to 22.24 kg ha−1 week−1). Results obtained from these simulated drift studies were compared with results obtained from 12 monitoring sites located at 1.6-, 4.8-, and 9.6-km distances from an operating natural-draft cooling tower at Chalk Point, Md. over the period 1975 to 1978.
No foliar injury symptoms associated with salt deposition were observed in either the simulation drift studies or cooling tower monitoring program during the investigation.
In the simulated drift studies, regardless of salt sources or deposition rates, yield, average price, value, quality index, total alkaloid, and total N contents were found to be highly variable and generally non-significant (p ≤0.05). However, trends for positive increases in yields were observed in four of the five studies at salt deposition rates ≤4.0 kg ha−1 week−1. No yield reductions were observed, even at salt deposition rates equal to 22.24 kg ha−1 week−1.
Statistically significant (p ≤0.05) increases in leaf Na and Cl contents, and decreases in metabolic index [MI = (% P + % K + % Ca + % Mg)/(% Na + % Cl)] values and leaf burn duration were observed with increased salt deposition rates in all five studies.
In the cooling tower monitoring program, no significant (p ≤0.05) differences were observed for yield, quality, burn, Cl contents or metabollic index value with respect to distances or years × distance interaction; however, year-to-year variation was significant. These resuits suggest that the operation of the Unit 3 cooling tower using brackish water was not having a significant impact on tobacco grown in the region.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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