Effluent Irrigation of Coastal Bermuda Grass

Abstract

Secondary effluent from the city of Tallahassee, Fla. was applied to coastal bermuda grass on lakeland fine sand. Effluent was applied through sprinklers at rates of 50 mm/week, 100 mm/week, 150 mm/week, and 200mm/week during the period April-October. Yields and nutrient recovery were determined. Yields and nutrient uptake showed an increase with irrigation rate, while efficiency of nutrient recovery decreased. The content (dry weight basis) of dry matter, nitrogen, phosphorus, and potassium increased with irrigation rate. Recovery efficiencies for calcium, magnesium, sodium, iron, and zinc were all below 100%, indicating adequate quantities of these elements. Based on these results, nitrogen recovery of 50% to 75% would be expected at 50 mm/week irrigation rate. With proper weed control, yields of 13 mtons/ha would be expected, with a harvest frequency of approximately 4 weeks. Supplemental potassium might be required since the K/N ratio of effluent usually lies below that of coastal bermuda grass.