Author
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Sikora, Lawrence |
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Enkiri, Nancy |
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Submitted to: Environmental Quality
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 12/2/2002 Publication Date: 1/15/2003 Citation: N/A Interpretive Summary: Phosphorus is now the key nutrient when applying manure. Accurate values of the phosphorus that is available for crop growth is important because this form of phosphorus is similar to the forms that dissolve in water and can reach waterways in runoff events. Eutrophication is often caused by an influx of phosphorus because so little phosphorus is required to cause an algal bloom. We compared triple super phosphate to poultry manure compost as a source of phosphorus fertilizer. Our hypothesis was as a compost poultry manure would have less fertilizer phosphorus than the manure and fertilizer because composting converts a portion of fertilizer nitrogen in manure to an unavailable form to plants. Results of a growth chamber study indicated that P in poultry manure was equal to triple superphosphate in providing phosphorus fertilizer to fescue. These data suggest that composting did not immobilize phosphorus as it does nitrogen. Reduction of phosphorus solubility in manures may be accomplished by adding phosphorus-binding chemicals such as aluminum or iron. These chemicals are found in some industrial by-products such as water treatment sludge. Technical Abstract: Phosphorus-based nutrient management requires that all sources of P materials including manures added to fields are accounted for in crop production plans. Use, treatment or manure disposal options are important issues and transforming the manure to compost and utilizing it off-farm is one viable utilization option. A study to evaluate plant available P in poultry manure compost (PMC) as compared to triple super phosphate (TSP) was conducted in a growth chamber using fescue (Festuca arundinacea Schreb). Phosphorus amendments from 0 to 150 mg P kg -1 soil were added to Sassafras soil (typic Hapludults) Fescue was harvested three times during a 84-day study and clippings as well as roots and crowns at the termination were analyzed for P content. Cumulative clippings dry weight was the same for both TSP and PMC and did not change with increased P application from 0 to 150 mg P kg-1soil. These data suggest that the Sassafras soil was not deficient in P and that the N application rate which was constant across all P treatments determined yields. Cumulative P uptake was the same for PMC and TSP and was linearly related to P application rate. At 84 days, greater P uptake was recorded for PMC 150 and 100 mg P kg -1 soil rates than for all other treatments suggesting greater P availability from PMC than TSP later in the growing season. Phosphorus content of roots and crowns was approximately equal to cumulative clippings P content. Because PMC was equal to TSP in supplying P for plant uptake, composting appears not to affect P availability in poultry manure. |
