Cropping systems for phytoremediation of phosphorus-enriched soils.
Eutrophication of freshwater bodies is frequently attributed to elevated phosphorus (P) concentrations in surface runoff from P-enriched agricultural soils. Forage and grain-cropping systems were compared for their effectiveness at remediating P-enriched soils. At each of four locations, one of three forage systems (Forage I = cereal rye silage and corn silage annually; Forage II = alfalfa; Forage III = annual ryegrass and corn silage annually) and the grain system (corn, small grain, and soybean rotation) were maintained for 3 yr on soils with five distinct initial soil P concentrations that were established by using four annual applications (1994-1997) of five different rates (0, 100, 200, 300, and 400 kg total P ha(-1) y(-1)) of poultry manure, dairy manure, or commercial fertilizer. Across all manure P treatments at all locations, the forage systems had greater removal of P than the grain system. Soil P concentration changes (2001-2004) did not reflect differences in crop P removal. Few significant reductions in soil P concentration were observed for either crop system. When reductions did occur, they were for the more highly enriched soil P treatments. No significant reductions in soil P concentration have occurred for the lowest manure P treatments. Considerable variability in crop P concentrations was observed among species at locations and among years produced. However, crop P concentrations did increase uniformly as soil P concentration increased, indicating that luxury consumption of P does occur in agronomic species produced on P-enriched soils.
Kratochvil
R J
RJ
Department of Natural Resource Sciences and Landscape Architecture, University of Maryland, College Park, Maryland 20742, USA. rkratoch@umd.edu
Coale
F J
FJ
Momen
B
B
Harrison
M R
MR
Pearce
J T
JT
Schlosnagle
S
S
D001673:Biodegradation, Environmental; D018556:Crops, Agricultural / Q000378:metabolism*; D000455:Medicago sativa / Q000378:metabolism; D010758:Phosphorus / Q000032:analysis / Q000378:metabolism*; D012434:Secale / Q000378:metabolism; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D003313:Zea mays / Q000378:metabolism
D012989:Soil Pollutants; D010758:Phosphorus