January 8, 2003 Abstract- "Phosphorus
Availability to Water from Animal Manures and Manure-Amended Soil"
January 8, 2003 Roundtable Minutes
Conclusions & Resolutions
- Phosphorus (P) chemistry is complex and not well understood.
- All manure-P is not in an organic form.
- Water-extractable P is a parameter more predictive of the amount of
P in runoff than other extraction techniques.
- Chemically and biologically, P from various sources (manure, biosolids,
fertilizer, etc.) does not behave the same.
o i.e. All P is not created equally.
Issue to Resolve
- A need exists for a standard protocol for determining water soluble
P in manure.
Research & Information Needs
Note: The following list is not prioritized
- Promotion of the concept that all manure-P is not organic-P.
- Development of species-specific manure-P management guidelines.
- Refinement of some P Index factors
o P extraction efficiencies with manure applications.
- Development of a broad "systems-oriented" approach for overall
manure management recommendations. Including . . .
o Cost - benefit analysis
o Decision tree
o Environmental parameters
- Development of new technology/engineering for the effective incorporation
of manure with minimal nutrient loss and loss of soil surface cover.
- Consider manure application history (in addition to soil test P values)
as a risk indicator for P loss.
- Explore further (i.e. replicate research) the influence of consecutive
years of manure applications on P losses.
o Research presented today found a greater loss of P from soils with
only one-or-two years of manure applications versus soils with 6+ years
of consecutive applications
- Investigate the relationships of the information presented today to
soil fertility and crop production.
- Examine the effluent from manure digesters for P availability and
solubility compared to other manures
- Explore relationships between soil test P, soil type, and extractable
P.
- Assess differences in P solubilities among dairy manures based on
storage (liquid vs. daily haul) and how these differences affect potential
runoff P losses.
- Assess effects of cumulative manure amendments on water soluble P
in a range of Wisconsin soils.
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