DISTRIBUTION OF DAIRY MANURE PHOSPHORUS SPECIES IN SOILS

Authors: He, Zhongqi; Griffin, Timothy; Honeycutt, Charles

Submitted to: American Society of Agronomy Meetings
Publication Type: Abstract Only
Publication Acceptance Date: 8/2/2004
Publication Date: 10/31/2004
Citation: He, Z., Griffin, T.S., Honeycutt, C.W. 2004. Distribution of dairy manure phosphorus species in soils. American Society of Agronomy Meetings.

Interpretive Summary:

Technical Abstract: Manure application rates are generally calculated to balance N input with crop requirements. This often results in over application of manure derived P. The impact of N-based manure application rates on soil P transformations should therefore be evaluated for efficient utilization of both manure N and P. In this study, we applied a sequential extraction procedure coupled with phosphatase hydrolysis to monitor P distribution at 0, 56 and 108 d of incubation with 11 dairy manures and inorganic fertilizers mixed with soils to provide 100 mg organic N kg-1 soil. The distribution patterns of inorganic P (Pi), enzymatically hydrolyzable organic P, and enzymatically nonhydrolyzable organic P followed similar changes observed for inorganic N amended soils. In H2O and NaHCO3 fractions, bioavailable P (Pi and enzymatically hydrolyzable organic P) increased linearly with added manure P. This work confirmed that a single application of manure impacted soil bioavailable P in a manner similar to fertilizer and did not significantly alter soil P properties. This means growers converting from conventional to organic practices (i.e. where manure is the sole source of N and P) may estimate manure bioavailable P to meet their short-term P needs.