| Popis: |
The effects of poultry litter stockpiles on nutrient availability and movement were evaluated for two soils from the major poultry-producing region in Maryland. The effect of covering 10.9 Mg stockpiles with tarps was compared to uncovered piles. An upland Coastal Plain soil (Evesboro sandy loam) and a lowland Coastal Plain soil (Othello silt loam) were used. A rainfall simulator was operated at 42 to 48 mm/h until runoff occurred for 1 h. Surface runoff was captured, and nutrient analysis was done for nitrate nitrogen (NO3-N), total Kjeldahl nitrogen (TKN), orthophosphate (PO4-P), and total phosphorus (TP) concentrations. Mass transport for each of these constituents was calculated from flow data. The variable that had the greatest effect on both hydraulic responses and nutrient fate and transport responses was soil type. Average NO3-N concentrations ranged from 2.75 to 9.80 mg/L, and for the sandy loam soil, wet AMC generated higher NO3-N concentrations than did dry AMC. Average NO3-N transported ranged from 6.5 to 1970.3 mg on the sandy loam and from 691 to 2821 mg on the silt loam. Average PO4-P concentration ranged from 0.21 to 10.78 mg/L. A two-way interaction between treatment and soil indicated that covering generated more runoff and higher peak flow rates than the uncovered piles. A two-way interaction between treatment and soil indicated that covering increased nitrate mass transport in surface runoff. There was no effect on PO4-P concentrations or PO4-P mass transport from covering the stockpiles for the Othello silty loam soil. |
