|SCHREIBER J D|
|MCDOWELL L L|
Submitted to: Mississippi Agricultural and Forestry Experiment Station Technical Bulletin
Publication Type: Experiment Station
Publication Acceptance Date: 5/1/1996
Publication Date: N/A
Interpretive Summary: Previous research on surface application of fertilizer has shown an increased amount of fertilizer nutrients in runoff and sediment. This research, using year-round measurements, showed that broadcasting fertilizer on no-till increased nutrients (N03-N, N04-P, and NH4-N) in runoff 2 to 3 times. Most of this greater loss was during the first month following fertilizer application. Concentrations of nitrate in the runoff from broadcasting were about 3 times as great as from inserted fertilizer. However, nitrate concentration from broadcasting exceeded 10 mg/L during only 1 storm in the 3 years of record.
Technical Abstract: Neither concentrations nor losses of total P or N in the sediment were affected by broadcasting fertilizer. Concentrations of NO3-N, PO4-P, and NH4-N in runoff from the broadcast-watershed were 3, 3, and 6 times, respectively, greater than from inserted-fertilizer watershed during the first 29 days after fertilizer application. During the same period, losses sof the nutrients in runoff from the broadcast-watershed were about 3, 3, and 5 times greater. Average annual losses of nitrogen (all in runoff) attributed to broadcasting were 6.4 kg/ha (5.8 kg/ha during the 29-day period after planting). Losses of phosphorus in the runoff due to broadcasting were 1.4 kg/ha (1/1 kg/ha in the period after planting). Broadcasting had little effect on nutrients lost during the period between harvest and next-year planting.