|Senwo, Zachary -|
|Tazisong, Irenus -|
Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 6, 2011
Publication Date: November 13, 2012
Citation: He, Z., Senwo, Z.N., Tazisong, I.A. 2012. Long-term dynamics of labile and stable phosphorus following poultry litter application to pasture soils. Communications in Soil Science and Plant Analysis. 43:2835-2850. Interpretive Summary: Phosphorus runoff from animal manure can contaminate surface water. Phosphorus is present in animal manure in different forms that differ in their availability to plants and microorganisms. Where the water soluble forms of phosphorus in animal manure pose an immediate risk of runoff (such as in storm events), other more resistant forms of phosphorus in manure may be transformed to available forms over time, increasing the overall amount of runoff phosphorus from manure to surface water. However, research is needed on the mechanisms of this phosphorus transformation. We found that long-term application of poultry litter increased phosphorus in pasture soils from a primary poultry producing area of Alabama. The greatest accumulation of phosphorus occurred in the surface 20 cm, implying a greater potential for phosphorus loss through surface runoff rather than from leaching. We found that the level of water soluble phosphorus increase from poultry litter was more related to the number of years of litter application, not the annual application rate or the cumulative amount of litter applied. This research showed that the history of poultry litter application on a given soil must be considered for managing phosphorus in an environmentally responsible manner.
Technical Abstract: Nonpoint-source agricultural P runoff can accelerate eutrophication of surface water ecosystems. Land-applied animal manure is sometimes identified as a source of runoff P from agricultural soils. We evaluated the quantities and forms of P from pasture soils in Alabama receiving poultry litter (PL) from 0-20 years. Sequential fractionation revealed different distribution patterns of P between these poultry litter-applied soils and poultry litter, suggesting that active transformation and interchange of different P pools in soil. The greatest accumulation of P occurred in the surface 20 cm, implying a greater potential for phosphorus loss through surface runoff rather than from leaching. Correlation analysis showed that stable P extractable by NaOH was related to the cumulative amount of PL applied. The levels of more stable or recalcitrant P in PL-applied soils did not correlate with any application parameter evaluated, suggesting the transformation of those forms to more labile P forms over time. The increase in water soluble P from poultry litter was more related to the number of years of litter application, than annual application rate or cumulative amount of litter applied. This research showed that the history of poultry litter application on a given soil must be considered for managing phosphorus in an environmentally responsible manner.