Abstract
The forage crops corn (Zea Mays), sorghum‐sudangrass (Sorghum Vulgare Pers. x Sorghum sundanese stapf.), and kenaf (Hybiscus cannabinus L.) were irrigated with municipal effluent at rates of 5, 10, 15, and 20 cm/week on Lakeland fine sand. Plant samples were collected weekly from each plot to measure green weight, dry matter, and nitrogen content. From these data crop nitrogen (kg/ha) was calculated for each week. Finally, uptake of nitrogen was calculated to determine efficiency of nitrogen recovery from the effluent as the crops matured. In all cases efficiency of uptake decreased with increasing application rates, as expected from fertility studies. For corn, efficiency of uptake continued to increase up to harvest. For sorghum‐sudangrass and kenaf a peak was reached at about 50 days after planting, after which efficiency of uptake declined rapidly.