Effluent Irrigation at Different Frequencies

The summer crops sorghum x sudangrass,Sorghum vulgare Pers. x Sorghum sudanese Stapf., corn silage, and corn grain, Zea mays L., were grown on Lakeland fine sand under irrigation with secondary municipal effluent. Irrigation rates of 2 in./week to 8 in./week (50 mm/week to 200 mm/week) were used. Yields and nutrient uptake increased with irrigation rate, while dry matter content and nutrient content remained relatively constant. Yields were lower than those of fertility studies. Split applications produced slightly higher nitrogen uptake over single applications for sorghum x sudangrass and corn silage at 6 in./week and 8 in./week (150 mm/week and 200 mm/week). Both methods gave comparable uptake at 4 in./week (100 mm/week) for all three crops.