We believe that a 100% increase would get their attention and that N rates would be
trimmed somewhat. This price increase/tax would also get them thinking about optimum
times of application, manure credits, etc. In other words, the whole issue of better N
management would be elevated to center stage if N prices were to double. Our
experience suggests that a behavioral change toward N management would take place.

On the other hand, a 500% fertilizer tax would cause bedlam and would definitely result
in a whole new approach to N management. We would like to see the authors comment
on the effect of a fertilizer tax on N management -- not just on the N rate vs. yield
response curve. If the extra 30-Ib N rate applied as "insurance" returns no extra yield, the
"insurance value" of the extra N takes on a different look and value when the cost of the
“insurance” is twice as high.

Also, we would like to see the authors discuss the effect of a fertilizer tax on fall-applied
N. It could be prorated depending on both geographic location and the time of N
application. For instance, earlier fall applications (warm soil temps on October 15) in
southern Corn Belt regions could have a higher tax than late-fall applications (cool soil
temps on October 15) in the northern regions.

Page 37 The 500,000 metric ton/yr reduction in N inputs for a 20% decrease in
feedlot runoff is too high in our opinion. See earlier comments.

Page 41 The last two paragraphs dealing with "adaptive management” and
"substantial time lags" are very refreshing. They are facts of reality and should be
emphasized in the Executive Summary.

Page 42 This message is well stated.

Pages 44-50 The Monitoring Needs and Research Needs sections are well done within
this NCR-195 Committee and are prioritized appropriately.

Sincerely,

Chart be. Lect

Charles W. Rice
Chair of NCR-195



Keith Kelling

Soil Science Dept.

1525 Observatory Dr.
University of WI - Madison
Madison, WI 53706-1299
608-263-2795
608-265-2595
kkelling@facstaff.wisc.edu

Gerald Miller
Agronomy Extension
2104 Agronomy Bldg.
Iowa State University
Ames, IA 50011
515-294-1923
515-294-9985
soil@iastate.edu

Tim Parkin

USDA, ARS

National Soil Tilth Laboratory
2150 Pammel Drive

Ames, Iowa 50011
515-294-6888

515-294-8125
parkin@nstl.gov

Gyles W. Randall

Southern Experiment Station
35838 120th Street

Waseca, MN 56093-4521
507-835-3620

507-835-3622
grandall@soils.umn.edu

Charles Rice

Dept. of Agronomy
Throckmorton Hall

Kansas State University
Manhattan, KS 66506-5501
913-532-7217
912-532-6094
ewrice@ksu.edu

Peter Scharf

Univ. of MO-Columbia
214 Waters Hall
Columbia, MO 65211
573-882-0777

FAX: 573-884-4317
scharfp@missouri.edu

James Schepers

USDA, ARS, Soil/Water Conservation
Research, University of Nebraska

119 Keim Hall

Lincoln, NE 68583-0934
402-472-1513

402-472-0516

jschepers1@unl.edu

Ron Turco

Dept. of Agronomy

Purdue University

Lilly Hall of Life Sciences
West Lafayette, IN 47907-1150
317-494-8077

317-496-2966
rturco@purdue.edu

Dale H. Vanderholm, Administrative
Advisor

207 Ag Hall

University of Nebraska

Lincoln, NE 68583-0704
402-472-2046

402-472-9071
dvanderholm2@unl.edu



2. To most, feedlot runoff implies a discharge from an animal feedlot or housing
area, and in this situation, is reaching a stream or river via overland flow/runoff.
Because this is a direct discharge into surface water policies and rules have been
directed at preventing this from happening during the last 10+ years. The
permitting process for siting of new feedlots or expansion of existing feedlots has
greatly curtailed these types of potential discharges. Consequently, we question
whether enough feedlot runoff exists in the MARB to generate a 0.5 million
metric ton/year decrease if the runoff was to decrease 20%.

3. To most people, improved manure management implies BMPs associated with
land application of animal manure. In our opinion, improved manure management
such as rate, time, and method of application/incorporation, could generate edge-
of-field N losses by 0.5 million metric tons/yr. However, "improving management
of manure" also appears as part of the first bullet in this set. Therefore, we would
suggest deleting "improving manure management" in the first bullet. In our
opinion, edge-of-field N losses could still be reduced about 1 million metric
tons/year by reducing "insurance" rates, applying appropriate credits for previous
crops and manure, and using improved soil N testing methods.

Page 35 Footnote 1 suggests a 10 to 15 bushels per acre corn yield response to an
extra 10 to 20 pounds of N fertilizer in a good year. This is ridiculous for at least two
reasons. First, we can expect a response of 1 bushel per pound of fertilizer N applied at
the low end of the response curve but not at the high end. The curve flattens following the
law of diminishing returns in good years and bad years. The corn yield response to an
extra 10-20 pounds of N (above the recommended rate of N) will likely range from 0 to
<5 bushel per acre. Second, the optimum rate of N has been shown to be similar in both
good and poor years in a number of long-term trials. This is because the plant gets its N
from both soil reserves and added fertilizer/manure.

In a poor year, dry climatic conditions frequently limit the availability of soil N because
of slower mineralization of soil organic matter, leaching, denitrification, etc. The plant
may also be less efficient with respect to N use; hence, a high N rate is needed even
though the yield is low. In a good year, climatic conditions normally optimize the
availability of soil N and plant N use efficiency is high. Therefore, high yields can be
obtained with the same rate of supplemental fertilizer/manure N as in a poor year because
of enhanced availability of soil N. The University of Wisconsin does not even include
yield goal in their equation to determine recommended N rates for corn. We suggest
deleting this part of the footnote.

Page 36 Models may suggest that "fertilizer taxes were predicted to be
economically inefficient, with a 500% tax required to reduce edge-of-field losses by
20%". This runs counter to our experiences. When N prices go from 12¢ to 18¢/pound of
N (only a 50% increase), farmers start to complain about the high cost of N and begin to
reexamine their application rates. Maybe they do not cut them, but they do give thought
to it.



NCR-195 MEMBERS

Gene Alberts

USDA, ARS

246 Agricultural Engineering Bldg.
University of Missouri

Columbia, MO 65211

573-882-1144

573-882-1115
Eugene_Alberts@muccmail.missouri.edu

James L. Anderson

Soil, Water & Climate Dept.
439 Borlaug Hall

1991 Upper Buford Circle
St. Paul, MN 55108-6028
612-625-8209
612-625-2208
jandersn@soils.umn.edu

Baker, James L.

219A Davidson Hall
Agricultural & Biosystems Engr.
Iowa State University

Ames, IA 50011-3080
515-294-4025

515-294-2552
jlbaker@iastate.edu

Bill Battaglin

U.S. Geological Survey
Box 25046, MS 406
DFC.

Lakewood, CO 80225
303-236-5950 x 202
whattagl@usgs.gov

Larry C. Brown

The Ohio State University

Department of Food, Ag. & Biological Engr.
200 Ag Engineering Bldg.

590 Woody Hayes Dr.

Columbus, OH 43210-1057

614-292-3826

614-292-9448

brown.59@osu.edu

Michael Burkhart

USDA, ARS, National Soil Tilth
2150 Pammel Drive

Ames, Iowa 50011
515-294-8125

515-294-8125

Paul Coreil, Assistant Director
Environmental Affairs

Louisiana Cooperative Extension Service
P.O. Box 25100

Baton Rouge, LA 70894-5100
225/388-2544

FAX: 225/388-4225
pcoreil@agctr.lsu.edu

Daniel Devlin

Dept. of Agronomy

2011 Throckmorton
Manhattan, KS 66506
913-532-5776
913-532-6094
ddevlin@oz.oznet.ksu.edu

Robert Dowdy

USDA, ARS, Soil & Water Management
Research, University of Minnesota

439 Borlaug Hall, 1991 Upper Buford Circle
St. Paul, MN 55108

612-625-7058

612-625-2208

bdowdy@soils.umn.edu



December 17, 1999 :
K is State University

Department of Agronomy

Crop, Soil, and Range Sciences

K-State Research and Extension

2004 Throckmorton Plant Sciences Center

Gulf of Mexico Hypoxia Working Group ioe otany es See ee eal

National Oceanic and Atmospheric Administration = Sy)
National Centers for Coastal Ocean Science

Room 9127

11305 East-West Highway

Silver Spring, MD 20910

Re: | Comments on the Integrated Assessment of Hypoxia
In the Northern Gulf of Mexico

The North Central Region (NCR-195) Committee titled “Mississippi River Watershed
Nutrient Sources and Control” was formulated a little over three years ago. Originally
the group operated under a NCT-167 designation. The Committee has three basic
objectives:

i Serve as a central information source and coordinating
body for agricultural issues relating to nutrient
loading from the Mississippi River to the Gulf of
Mexico.

2. Coordinate, promote and facilitate multi-state research, educational and extension
programs to help individual states deal with their impacts of surface water loading
from nutrients.

3. Continuously review current knowledge and technologies
with respect to their impact on nutrient management for water quality.

The committee will be linked electronically to facilitate communication. The committee
will meet at least yearly to assess issues around the region and progress toward action
items. The meetings will, when possible, be coordinated with other hypoxia-related
meetings in the region and nationally, and with policy meetings in Washington. The
committee will also sponsor scientific exchanges and will provide a talent pool for other
regional efforts directed toward hypoxia. The committee will assemble available
research information that pertains to the problem and will develop educational and
demonstration programs that will aid in problem solving.

Given the expertise on this topic, we believe it is appropriate to make the following
observations about the Integrated Assessment of Hypoxia in the Northern Gulf of Mexico
Report. Our comments are as follows.

Kansas State University
Agricultural Experiment
Station and Cooperative
Extension Service

“Knowledge
porLife”



John Downing

Dept. of Animal Ecology
Towa State University
Ames, IA 50011-3221
515-294-2734

FAX: 515-294-7874
downing@iastate.edu

Norman Fausey

USDA ARS Soil Drainage Res U
590 Woody Hayes Dr.
Columbus, OH 43210
614-292-9806

FAX: 614-292-9448
fausey.1@osu.edu

Jane Frankenberger

Ag & Biological Engineering
Purdue University

1146 Ag & Bio Engineering Bldg.
West Lafayette, IN 47907-1146
317-494-1356

317-496-1115
frankenb@purdue.edu

Terry Francl

American Farm Bureau Federation
225 Touhy Avenue

Park Ridge, IL 60068
847-685-8769

FAX: 847-685-8969
terry@fb.com

Tom Franti

Biological Systems Engineering
234 LW Chase

University of Nebraska
Lincoln, NE 68583-0726
402-472-9872

402-472-6338

tfranti@unl.edu

Don Goolsby

USS. Geological Survey
Mail Stop 406

Denver Federal Center
Lakewood, CO 80225
dgoolsby@usgs.gov

Robert G. Hoeft

N305 Turner Hall

1102 S. Goodwin Avenue
N305 Turner Hall

1102 S. Goodwin Avenue
Urbana, IL 61801
217-333-4424
217-333-5299
rhoeft@uiuc.edu

Maurie Horton

USDA - CSREES

Natural Resources & Environment
Ag Box 2210

Washington D C 20250-2210
202-401-4504 or 5971
202-401-1706
mhorton@reeusda.gov

John R. Jones

112 Stephens Hall

University of Missouri

Columbia, MO 65211
573-882-3543

573-884-5070
snrjones@muccmail.missouri.edu

Dennis Keeney

209 Curtiss Hall Leopold Center
Iowa State University

Ames, IA 50011-1050
515-294-3711

515-294-9696
drkeeney@iastate.edu



As we look at this section titled, “Reduction Effects and Approaches,” we are concemed
about the overall approach of this report.

Comments

Page 8 The two paragraphs in the "Potential futures if current activities are
unchanged" section are really pessimistic and does not even suggest the possibility of
improvement over time. Verbs such as "could produce", "may increase", "may be offset",
"will tend to increase", and "could lead” all suggest to the reader that hypoxia will get
worse. This seems a bit speculative, especially since these large biological systems are so

slow to respond.

Page 18 We were pleased to see the paragraph addressing "climate change.”
However, it seems unlikely that climate change has had greater impact over the long run
than has human activities. Most likely both have had an impact. It should be
acknowledged, however, that it is difficult to disaggregate these impacts, at least in any
precise or scientific terms given our current state of knowledge.

Page 20 The last paragraph on page 20 and continued on top of page 22 describes
the long-term drainage basin changes very well. This is very important future research
issue.

Page 22 The last sentence in the middle paragraph comments on the size of the
hypoxic zone in 1999, We have not seen any 1999 nitrate concentration or flux data from
the MARB to support this statement. If the data exist, then they should be cited.
However, if it is speculation, then the sentence should be deleted.

Page 23 The second to last paragraph states that "precipitation leaches the highly
soluble nitrate from the soil into streams via overland runoff, ground-water discharge,
and agricultural drains". Research consistently shows ground-water discharge and
agricultural drains to contribute much more nitrate to streams than overland runoff. In
fact, nitrate losses in overland runoff are usually discounted because they are so small.

About the only exception is a scenario where a nitrate source of fertilizer is applied to the
soil surface and not incorporated and is quickly followed by an intense rainfall event that
would result in some runoff of the fertilizer N. That scenario is not likely because most N
fertilizers applied are ammonium-based and need to be nitrified in the soil to nitrate.
Second, most nitrate on the soil surface will be incorporated into the soil by the first 5 to
10 mm of rain.

Page 23 In the last paragraph it is stated that "soils in this region contain large
amounts of nitrogen,...". It would be more correct, and informative, and less confusing if
the sentence said "soils in this region contain large amounts of organic matter, a portion
of which converts to soluble nitrate each year."



Page 34 The first bullet at the bottom of the page under "Reducing Inputs" is
understandable for those of us that know what "agronomically recommended rates"
entail. However, to many this statement taken by itself could easily imply regulatory
limitation rather than BMP adoption to achieve the applications of agronomic rates. The
first bullet in the middle of page 35 does a good job of explaining the major BMPs to
achieve the application of proper agronomic rates; unfortunately, it is disconnected from
the bullet on page 34. These two points should be integrated together in one place.

Page 35 The first bullet suggests that discharge of nitrogen to streams can be
reduced by switching from conventional tillage systems to ridge-till or other reduced
tillage practices, This is true if you are only concerned about total N, because less erosion
occurs with conservation tillage systems. However, if the primary form of N relating to
hypoxia is nitrate, the literature does not suggest or support any consistent effect of
tillage system on nitrate losses/flux in subsurface drainage water. All of the other bullets
in this section relate to nitrate, so including tillage and total N in this section is not
appropriate as it stands in this draft.

Page 35 The second bullet suggests that tile lines are normally spaced at 5 to 10
meters. This is not true as lateral lines are frequently spaced at 20 to 30 meters. The point
of the discussion in chapter 5 was to point out the likely probability of increased nitrate
losses with reduced spacings between tile lines. As stated in section 3.1.8, "inferences
drawn from this work suggest that narrowing drain tile spacing to <20 m could result in
greater losses of nitrates compared to wider spacings".

Page 35 The last bullet discusses "Improved management of feedlot runoff". We
are very uncomfortable with this discussion. In chapter 5, very little was said about
feedlot runoff. It was not mentioned in the Executive Summary or in the Conclusions
section (section 6). There was a small section (paragraph 1.3.2 and Table 1.2) that dealt
with feedlot discharges. Also, in this paragraph, manure/feedlot contributions of N were
cited in Table 1.1 and were calculated to be about 40% of the fertilizer N used in the
MARB.

Unfortunately, in section 4 of Chapter 5 (specifically 4.2 and Table 4.1), improved
management of animal manure and subsequent runoff in livestock producing areas.......
and feedlot runoff were co-mingled. The result was a statement in Table 4.1 indicating a
0.5 million metric ton N/year reduction with "improved manure management" and does
not mention feedlot runoff. Yet, this bullet in the Integrated Assessment indicates "a 20%
decrease in feedlot runoff could decrease edge-of-field nitrogen loss by 0.5 million metric
tons/year". This illustrates how the terms "feedlot runoff" and "manure management"
have been interpreted to mean one and the same when they are different measurements,
They are really apples and oranges.

Our concerns with this bullet are:

1, The confusion between the terms "feedlot runoff" and "manure management."