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September 10, 2002 "Phosphorus Losses from Turf"
September 10, 2002 Roundtable Minutes
Conclusions & Resolutions
- A healthy lawn is more effective in controlling runoff than an unhealthy
lawn.
- Relative to impact on soil test P, the ratio of N:P2O5 is more important
than fertilizer grade.
- N supply drives nutrient uptake.
- Lawn aeration (coring) does not increase soil infiltration.
- Situations exist where P and potassium (K) fertilization of turf is
not required.
- Vegetation is a major source of P in runoff from lawns.
- The majority of P contained in runoff from turf occurs during the
late winter months (i.e. thawing/melting periods).
Issues to Resolve
- The source of P runoff in turf. How much from fertilizer, soil, vegetation?
- From a P loss standpoint, is the practice of returning clippings to
turf good or bad?
- Are there best management practices for minimizing vegetative-P losses
from turf?
- Soil testing of turf:
- Do Bray-P1 values correlate to runoff-P losses from turf?
- Is Bray-P1 an appropriate soil test for turf?
- Need for turf-specific soil sampling strategies (i.e. depth of sampling,
extractant, etc.)?
Research & Information Needs
- Promotion of the merits of zero phosphate fertilizers
- If soil test allows for them
- Follow-up monitoring of P loadings to water bodies after regulations
(such as zero-P fertilizer use) are passed (i.e. determine if the regulation
is working).
- Need to investigate and characterize water bodies to determine sources
and loadings of P prior to the passing of regulations/restrictions (i.e.
will the proposed reduction in P loading of the regulation be enough
to have any affect on improving water quality?)
- Education of lakeshore residents on the amount of time required for
water quality improvements to become evident after the installation
of best management practices.
- Education of lawn and garden center staff on "proper" turf
fertilization.
- Determine P losses from shrub areas and flower beds.
- Explore suitable ground covers for areas where turf will not thrive
(such as areas of less than 70% sunlight).
- Investigate the effect of various mulching materials on P loadings.
- Promote proper grass clipping discharge practices.
- Keep out of curb, roadways, driveways, etc.
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