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Phosphorus Species Composition of Poultry Manure‐Amended Soil Using High‐Throughput Enzymatic Hydrolysis
Author(s) -
Johnson Nicholas R.,
Hill Jane E.
Publication year - 2010
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2009.0431
Subject(s) - chemistry , manure , phosphorus , ethylenediaminetetraacetic acid , enzymatic hydrolysis , enzyme , soil test , compost , hydrolysis , composition (language) , environmental chemistry , molybdate , biomass (ecology) , agronomy , soil water , biochemistry , environmental science , biology , chelation , organic chemistry , soil science , linguistics , philosophy
Nutrient management planning tools including P indices would have enhanced diagnostic and predictive abilities if forms of organic P transformable to inorganic phosphate by soil microbes (enzyme‐labile P) can be assessed. Enzyme‐labile P species were tracked in a time series of manure‐amended soil samples by modifying an enzymatic P assessment tool first developed by Zhongqi He for manures. By adapting this method to a microplate reader format, up to 96 samples were processed simultaneously. Enzyme measures were compared with those made on the same samples using solution 31 P nuclear magnetic resonance spectroscopy. Enzymatic tracking of P species in manure‐amended soil extracts is robust; 25 to 36% of P extracted by NaOH–ethylenediaminetetraacetic acid was liberated as orthophosphate after incubating samples with enzymes. These increases in molybdate‐reactive P (MRP) due to enzymatic hydrolysis exceeded MRP detected in bicarbonate extracts, suggesting the true bioavailable fraction of soil P is underestimated using traditional, static tools such as Olsen P or Mehlich‐3 P. This efficient assessment tool should enhance our ability to assess P classes and enzyme‐labile P in manure‐amended soil.