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United States Department of Agriculture

Agricultural Research Service

Title: Organic Phosphorus Source Affects on Calcareous Soil Phosphorus and Organiccarbon

Authors
item Robbins, Charles
item Freeborn, Larry
item Westermann, Dale

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 6, 1999
Publication Date: N/A

Interpretive Summary: Recent increases in the number of confined feeding and dairy operations in the Intermountain West require disposal of ever increasing quantities of manure and whey. Both materials add large quantities of phosphorus to the application sites over time. Many states are starting to regulate how and when these wastes are land applied. Most of the data available for making these decisions were not obtained on high lime soils or in arid or semi-arid areas. A high lime topsoil and freshly exposed subsoil were fertilized with inorganic phosphorus fertilizer, dairy manure and cheese whey and then the plant available and soluble phosphorus was monitored for eight years. Organic matter added with the whey did not influence soil organic matter concentrations while the organic matter added with the manure doubled the subsoil organic matter and increased the topsoil organic matter concentrations. All measured phosphorus concentration forms were linearly related to soil organic matter concentrations but were not related to the amount of ortho, organic or total phosphorus added to the topsoil or to the subsoil. These results suggest that organic waste application rates to arid high lime soils should be based on soil test results rather than phosphorus application rates.

Technical Abstract: Recent increases in confined feeding operations in the Intermountain West require disposal of ever increasing quantities of manure and whey. Both materials add large quantities of P to the application sites over time. Many states are starting to regulate how and when these wastes are land applied. Most of the data available for making these decisions were not obtained on calcareous soils or in arid or semi-arid areas. A Portneuf silt loam (Coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids) topsoil and freshly exposed subsoil were fertilized with inorganic monocalcium phosphate (MCP), dairy manure and cheese whey. Twice as much P was added with the whey as with the manure. Nearly equal amounts of organic matter were added with the whey and manure. Organic matter added with the whey did not influence soil Organic Carbon (OC) concentrations while organic matter added with the manure doubled the subsoil OC and increased the topsoil OC concentrations. Changes in OC and ortho- and organic-P concentrations in sodium bicarbonate extracts and saturation extracts were measured once or twice a year for eight years. All four P concentration forms were linearly related to soil OC concentrations but were not related to the amount of ortho, organic or total P added to the topsoil or to the subsoil. These results suggest that organic waste application rates to arid calcareous soils should be based on soil test results rather than P application rates.

Last Modified: 9/10/2014
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