Agricultural Nutrient and Sediment Reduction Workgroup
Conference Call
August 2, 2007

Purpose: The purpose of this conference call was to find out how UMD addressed the
workgroup's concerns regarding the UMD/MAWP BMP efficiency recommendations
(see 7-12-07 minutes) and to come up with final recommendations from the workgroup
for year 1 BMP efficiencies. The workgroup's recommendations will be presented at the
August 6th Tributary Strategy Workgroup meeting.

Handouts

•	Minutes 7-12-07

•	Conservation Planning UMD/MAWP Recommendation

•	Conservation Tillage UMD/MAWP Recommendation

•	DRAFT Cover Crops UMD/MAWP Recommendation

•	Off-stream Watering with Fencing, Off-stream Watering without Fencing, Off-stream
Watering with Fencing and Rotational Grazing Practices UMD/MAWP
Recommendation

*Handouts can be accessed at the following website:

http://www.chesapeakebav.net/calendar.cfm?EventDetails=9017&DefaulfVriew=2
Minutes

•	The conference call began at 1:30 pm. Introductions were made and the meeting's
agenda was reviewed. There were no corrections on the meeting minutes of 7/12/07.

•	Tom Simpson, UMD, and Sarah Weammert, UMD, explained how they have
addressed the main issues that were brought up by the workgroup at the July 12th
meeting.

•	Issue 1: For the off-stream watering with/without fencing BMP, the workgroup
recommended that the livestock shading requirement be removed from the stream
protection without fencing definition.

o DECISION: UMD accepted the workgroup's recommendation. Shade should
not be a requirement for this practice, although they suggested saying in the
definition that shading should be encouraged where applicable.

•	Issue 2: For the off-stream watering with/without fencing BMP, the workgroup
recommended that the efficiencies for the without-fencing category be reduced to
increase the difference between this category and the with-fencing category. A higher
efficiency is primarily proposed for this category because some states require at least
a 35-foot setback for the fencing.

o VA requires a 35-foot setback.

o A 35-foot setback is not in MD's requirements. It is site specific.

o A 35-foot setback is standard now in PA, but in the past it was 12 or 15 feet.

o UMD stated that off-stream fencing has been used to refer to the act of simply
fencing cattle out of the stream and it isn't tied to width.

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o DECISION: UMD will not change their recommended efficiencies for the off-
stream watering practices. However, in order to address the workgroup's
concerns, they agreed to recognize that when a wide area is fenced off (such
as with a 35-foot setback), it should qualify as two practices: stream
protection and a buffer for pasture. The workgroup accepts this suggestion,
unless Russ Perkinson (who brought up this issue at the last meeting and is not
in attendance today) has any objections. If he does, then this issue will be
brought back to the workgroup at a later date.

Issue 3: The workgroup recommended that phosphorus efficiencies be set 5% lower
than sediment efficiencies as a general rule to account for dissolved phosphorus
losses not associated with soil losses, unless the scientific research indicates
differently.

o UMD supports the recommendation that TP efficiencies be set lower than TSS
efficiencies; however they suggest that the TP efficiencies be lowered by 10%
rather than by 5%. They favor 10% because it implies that there is a
significant difference and because it does not indicate a greater level of
precision than we have. However, they will defer to the workgroup regarding
what percentage is used,
o Some members voiced concern that subtracting 10% from TP will affect some
BMPs more than others. For example, if the original efficiency is 40% and it
is lowered to 30% than it is only reduced by 25%, whereas if the original
efficiency is 20% and it is lowered to 10% than it will be reduced by 50%.
o DECISION: In order to make the reductions more proportional, UMD and the
workgroup agreed to reduce TP by 25%, rather than simply subtracting 10%.
This was based on research findings which suggest that 25% of TP are
attributable to Dissolved Reactive Phosphorus (DRP) according to the UMD.

Issue 4: In regards to cover crops, one workgroup concern is that the numbers in the
table are just addressing ground water sources and they think that there needs to be
some accounting for surface water.

o UMD said that cover crops are no more effective at removing TN than TP.
The TP numbers that are in the table are for surface and subsurface with the
assumption that there is only a minimal subsurface component,
o They do not think that they can justify making the TN numbers any higher

than the TP numbers for surface water,
o Although it does vary some across the region, overall about 75% of nitrogen

tends to move through groundwater subsurface paths,
o UMD thinks that the most appropriate way to address this may be to
contribute 75% of the subsurface TN reductions in the table; apply a 25%
multiplier to the surface TP efficiencies, and then add the two values together
so that you obtain a weighted average of surface and subsurface flow. Jack
Meisinger agreed that this is a good way to go. UMD sent this idea to Ken
Staver, but they have not heard back from him yet.
o In the current report, no distinction is made between soil association

properties. The workgroup is concerned about this because there do tend to be


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differences between regional soil groups. Because of this, UMD will look into
dividing the watershed up into three or four regions. Potential regional soil
groupings are: 1) the coastal plain and karst soils at 80%; 2) the piedmont
soils at 70%; and 3) glaciated and shale soils at 60%. Tom will email the
workgroup the actual recommendations for the divided regions after he
verifies whether or not the proposed groupings and percentages are correct,
o Q: Is this number a recharge number or a pollution number? We need to
recognize that gully washers contribute to a significant amount of nutrient
runoff.

¦ A: They are basing it on a 1996 review that split out relative amounts
of nitrogen transport by pathways. It looked at how nitrogen was being
routed and not how water was being routed,
o Nitrogen and phosphorus have different sources of transport pathways,
o UMD is proposing that the table on page 4 of the cover crop recommendation
document be used to deal with the subsurface component, and then a weighted
average be done for surface loss,
o UMD will look back at the study that looked at this to see how they portioned
out the subsurface vs. the surface pathways for various regions and to see how
they looked at nitrogen transport compared to water transport. UMD will try
to report their findings to the workgroup quickly,
o UMD agreed to add in citation information above the tables on pages 3 and 4.

• Issue 5: Today, the workgroup expressed concern over the variation in efficiency
values for the different methods of cover crop seeding.

o In the UMD recommendations, it says that for fly-on seeding, 50% of all

efficiency values should be used (see page 4).
o In MD, payments are only given for cover crops that have at least 80%

vegetative cover. Therefore, since good coverage is required, the efficiencies
should not vary based on whether or not it was flown over or drilled,
o UMD said that their cover crop group had data that they felt showed that there
tended to be less uptake with fly-on compared to drilling. Fly-on may be more
variable because it is more dependent on good conditions,
o Regarding the efficiencies on page 3 for late planting (2 weeks or more after
the first frost), UMD explained that these were included because the cover
crop group decided that some cover crops were better than no cover crops,
even though the literature showed that you were going to get limited growth
and nutrient uptake,
o The workgroup agreed that they were okay with the late planting numbers,
o MD had concerns about basing the efficiencies on species of cover crops and
their inability to track them at the present time. They would like to see some
discussion in the results to indicate the discussion that the workgroup had at
the July AgNSRWG meeting that looked at adjusting averages where species
tracking is not available. Basically, this would reduce the defensibility of the
watershed model's predictions,
o Other workgroup recommendations for cover crops:

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¦	Provide an explanation in the paper as to why aerial seeding has lower
efficiency values than drilling and cite the references.

¦	Explain why they recommended using 75% of the literature values
(above table on page 4).

¦	Include more information on why late planting was included.

¦	Have an 80% stand as a benchmark for efficiencies across all
categories (drilling and fly-on). If fly-ons meet this stand percentage,
then they could use this reduction. If they do not meet this, then they
would need to use the other fly-on efficiency currently listed in the
report, which is a 50% reduction. There would need to be
documentation that there is an 80% ground cover by early December.
Aerial seeding would be removed from the table. (UMD stipulation-
Somewhere in the report it should say that getting consistent stands
with aerial seeding is difficult and that aerial seeding can have very
low uptake.)

o UMD agreed to make the first three revisions. They are also okay with the

fourth revision and will run it by the cover crop group,
o DECISION: The workgroup will see what changes UMD makes to the cover
crop report before they give their final recommendation for this practice.

•	MD questioned why the majority of cover crop categories did not include TP and TSS
efficiencies. The cover crop group did consider this question; however they decided
to leave the efficiencies as they were. Mark will run this issue by Tom and Sarah
since they are no longer on the call. This is an important message to bring up as a
workgroup.

•	As a general suggestion, the workgroup recommended that UMD continue to think
about how we connect the reduction to the load. The efficiencies need to be relevant
to the loads.

•	The workgroup decided to accept the UMD recommendations with the agreed upon
adjustments for the agricultural practices. The only exception was for the cover crop
practices which will require additional revisions prior to final review by the
workgroup.

•	Mark will prepare the draft workgroup recommendations for review prior to the
Tributary Strategy Workgroup meeting.

•	Mark will present the workgroup's position at the August 6th Tributary Strategy
Workgroup meeting. Information on this meeting can be found at
http://www.chesapeakebav.net/calendar.cfm?EventDetails=8816&DefaultView=2.

•	The meeting was adjourned at 3:00 pm.

Participants

Sally Bradley
Kari Cohen
Mark Dubin
Beth Horsey
David Kindig

CRC
NRCS

UMD-MAWP

MDA

VADCR

sbradlev@chesapeakebav.net
kari. cohen@md.usda. gov
mdubin@chesapeakebav.net
horsevea@mda.state.md.us
david.kindig@dcr.virginia.gov

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Bill Rohrer	DDA

Kristen Saacke Blunk	Penn State

Jennifer Schaafsma	MDA

Tom Simpson	UMD

Helen Stewart	MD DNR

Sarah Weammert	UMD

William.Rohrer@state.de.us
kls386@psu.edu
schaafi a@mda. state, md.us
tsimp son@umd. edu
hstewart@dnr. state.md.us
sweammer@umd. edu

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