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United States Department of Agriculture

Agricultural Research Service

Research Project: Value-Added Products from Cottonseed

Location: Commodity Utilization Research

Title: Inorganic and enzymatically hydrolyzable organic phosphorus of Alabama Decatur silt loam soils cropped with upland cotton

Authors
item Tazisong, I -
item He, Zhongqi
item Senwo, Zachary -

Submitted to: Soil Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 21, 2013
Publication Date: August 1, 2013
Citation: Tazisong, I.A., He, Z., Senwo, Z.N. 2013. Inorganic and enzymatically hydrolyzable organic phosphorus of Alabama Decatur silt loam soils cropped with upland cotton. Soil Science. 178(5):231-239.

Interpretive Summary: Alabama was historically known as "The Cotton State". It now ranks 4th with 10.1% of U.S. cotton production. Various conservation tillage practices have been used in cotton production for reducing surface runoff and erosion and for increasing soil moisture in Alabama. It is believed that management practices would affect the distribution and fate of phosphorus (P) forms in these cotton soils. In this study, we assessed the forms and lability P in the Alabama Decatur silt loam cotton soils, and evaluated the impact of management practices on the soil P forms. Our data show that soil inorganic P in this study was mainly associated with Fe and Al oxides and was not readily bioavailable. We observed changes of the distribution of both inorganic and organic P fractions in these soils, indicating that management and tillage practices, coupled with manure and inorganic fertilizer applications, affect the fate of P forms in soils. Generally, the influences in soils treated with poultry litter were lower than in soils treated with inorganic fertilizer.

Technical Abstract: Alabama is one of top cotton production states in the USA. It is believed that management practices would affect the distribution and fate of phosphorus (P) forms in these cotton soils. In this study, we assessed the forms and lability P in the Alabama Decatur silt loam cotton soils, and evaluated the impact of management practices on the soil P forms. The data show that inorganic P in these soils was mainly associated with Fe and Al oxides and was not readily bioavailable. On the other hand, elevated level of water, Fe and Al inorganic P was observed in soils treated with poultry litter than in the control and some treated with inorganic fertilizer. The majority of the soil organic P was associated with Al oxide (> 40%) except in no-till and control treatments where the bulk of the soil Po was organic matter bound. Water soluble organic P increased after poultry litter applications while no increase was observed with inorganic fertilization. Greater than 50% of organic P in the sequentially-extracted NaOH fraction was hydrolysable by various phosphatase enzymes, which suggested that NaOH-extractable organic P is labile. Any portion of organic P extracted in the fractions that was not hydrolyzed by the enzymes is considered to be in more complex forms tightly bound to colloidal materials. Soil manure application also influenced enzymatically hydrolyzable organic P as relevant enzymatic activities in soils treated with poultry litter were lower than in soils treated with inorganic fertilizer.

Last Modified: 4/20/2014
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