71st SWCS International Annual Conference July 24-27, 2016 Louisville, KY

1. Nitrogen and Phosphorus
Consumption and Balance in the
Mississippi River Basin: 1987 to 2012
C.S. Snyder, PhD, CCA
Nitrogen Program Director, IPNI
Conway, AR
SWCS Meetings
Louisville, KY August 24-27, 2014 www.ipni.net
T. Scott Murrell, PhD
Director, North America, IPNI
West Lafayette, IN
Q. Rund and R. Williams
PAQ Interactive
Monticello, IL
P.E. Fixen, PhD
Senior V.P., Americas and Oceanic Group, and
Director of Research, IPNI
Brookings, SD

2. We have addressed N
and/or P management,
balances, and loss from
MARB to Gulf of Mexico ….
in science presentations at
ASA and SSSA meetings:
2009, 2012, and 2014

4. Drains 41% of
contiguous 48 states
Includes parts or all of
31 states
Flow speed:
Headwater ~ 1.2 mph
New Orleans – 3 mph
Missouri/Mississippi
Rivers combined:
• 4th longest river
in world:
o 3,710 miles or
o 5,970 km
• Miss. R. alone: ~2,300
miles
Mississippi River Facts - https://www.nps.gov/miss/riverfacts.htm
Louisville

5. MARB Sub-Basin Drainage Area
Sub-basin Drainage Area
% of MARB
Drainage Area
km2 million
hectares
million
acres
MO 1,353,300 135 334 43.1
Arkansas/Red 584,100 58 144 18.6
OH-TN 525,800 53 130 16.7
Upper Miss. 493,900 49 122 15.7
Lower Miss. 183,200 18 45 5.8
TOTAL MARB 3,140,300 314 776 99.9
U.S Cropland Area
Used for Crops ~335
U.S. total land area –
lower 48 states ~1,894
http://toxics.usgs.gov/pubs/of-2007-1080/discussion_5large_basins.html
http://www.ers.usda.gov/data-products/major-land-uses/.aspx#25964

6. <1
1 to 10
10 to 100
100 to 500
500 to 1000
>1000
<0.01
0.01 to 0.1
0.1 to 1.0
1.0 to 5.0
5.0 to 10.0
>10.0
kg km-2 yr-1 lbs/A/yr (approx.)
USGS Estimates of Loss and
Delivery of N and P to the Gulf
SPARROW - Modeled Estimate of N and P
Discharge in Watersheds of the Mississippi R. Basin
Alexander et al. 2008. Environ. Sci.
& Technol. 42(3): 822–830 (USGS)

7. SPARROW Modeled Sources of Nutrients to
the Gulf of Mexico (USGS)
Robertson and Saad. 2013. J. Environ. Qual. 42:1422–1440
Total N

8. SPARROW Modeled Sources of Nutrients to
the Gulf of Mexico (USGS)
Robertson and Saad. 2013. J. Environ. Qual. 42:1422–1440 (USGS)
Total Phosphorus

9. Economic Value of Total N and P2O5 Delivered
to Gulf of Mexico from Miss. & Atchaf. Rivers
Nutrient Average Annual Sum Since 1980
Million $ Billion $
Total N 1,312 45.9
Total P2O5 262 9.2
Making it relevant to Arkansas
Arkansas fertilizer consumption, year ending June 30, 2012:
Tons of N = 294,448 tons
Tons of P2O5 = 75,957 tons
• IF we assume N and P2O5 valued at $0.45 and 0.40 per lb, respectively
• Then, gross 2012 (annual) value of Arkansas fertilizer N and P2O5
Arkansas fertilizer N = ~ $265 million
Arkansas fertilizer P2O5 = ~ $61 million

10. Objectives
• For available data in MARB, 1987 to 2012 :
– Compare 5 major sub-basin ANNUAL Total N and Total P flux to
northern Gulf of Mexico against:
• Fertilizer N and P input
• Excreted manure N and P input
• Total N and P input
• Crop harvest removal of N and P
• Net annual N and P balance per cropland area
• Data/information sources for MARB
• Nutrient flux – USGS ( B. Aulenbach et al.) using LOADEST
AMLE: http://toxics.usgs.gov/pubs/of-2007-
1080/large_subbasins_flux.html
• Crop harvested area – USDA NASS
• Fertilizer consumption (annual) - AAPFCO & TFI
• MARB nutrient metrics – IPNI NuGIS (includes 21 crops)

11. NuGIS History
• Development began in 2006 (6-yr effort)
• Preliminary NuGIS – Summer of 2010
– Bulletin & web tool
– Reviewed and extensively revised
• Final version - Nov. 1, 2011
– Improved accuracy
– Export data files and maps
– Data from 1987-2007; 2008-2011 added
• Final “Final version” – Jan. 13, 2012
– Improved procedure for estimating nutrient
removal by “other crops”
• Census years 1987-2007; annual data
since
http://www.ipni.net/nugis

12. Methods – basic model
A simple partial nutrient balance algorithm
Farm
fertilizer
Recoverable
manure
Biological
N fixation
Removal
by crop
harvest
Partial
nutrient
balance
Not considered:
• Atmospheric deposition
• Nutrients in irrigation water
• Biosolids application
• Soil erosion
• Gaseous N emissions or leaching
1987 to 2007 in 5-yr increments set
by Census of Agriculture (COA)
Annual
increments
since 2007

13. IPNI NuGIS data http://nugis.ipni.net/About%20NuGIS/
MARB N Input, Crop Harvest Removal,
and Net Balance, 1987-2012*
* 1987 to 2007 Ag Census years, harvest removal from 3-year average crop yields

14. IPNI NuGIS data: http://nugis.ipni.net/About%20NuGIS/
MARB P2O5 Input, Crop Harvest Removal,
and Net Balance, 1987-2012*
* 1987 to 2007 Ag Census years, harvest removal from 3-year average crop yields

16. RESULTS - Nitrogen

17. RESULTS - Phosphorus

18. RESULTS - Nitrogen
R‐square for relationships
Total N flux from sub‐basin to northern Gulf of Mexico
(Y variable) vs.
Sub‐basin
Net N
balance,
tons
Net N
balance
PPCA,
lb/A
Fert. N
input,
tons
Excreted
manure N
input, tons
Fert. + excr.
manure N,
input, tons
Ark‐Red 0.003 0.006 0.000 0.028 0.008
Lower Miss 0.409 0.373 0.083 0.000 0.070
MO 0.208 0.192 0.012 0.081 0.031
OH‐TN 0.082 0.126 0.365 0.046 0.213
Upper Miss 0.510 0.486 0.002 0.095 0.006

19. Total N Flux vs. Sub-basin Net N Balance
y = 1.6625x ‐ 94940
R² = 0.40864
‐300,000
‐200,000
‐100,000
0
100,000
200,000
300,000
400,000
500,000
‐50,000 0 50,000 100,000 150,000 200,000
TotalNflux,metrictons/year
Net N balance, short tons
Lower Miss. , Total N flux vs. Net N Balance

20. RESULTS - Phosphorus
R‐square for relationships
Total P flux from sub‐basin to northern Gulf of Mexico
(Y variable) vs.
Sub‐basin
Net P
balance,
tons
Net P
balance
PPCA,
lb/A
Fert. P2O5
input,
tons
Excreted
manure
P2O5 input,
tons
Fert. + excr.
manure
P2O5 input,
tons
Ark‐Red 0.000 0.000 0.032 0.110 0.099
Lower Miss 0.231 0.321 0.064 0.016 0.065
MO 0.164 0.170 0.116 0.213 0.040
OH‐TN 0.152 0.135 0.119 0.108 0.046
Upper Miss 0.313 0.316 0.000 0.025 0.003

21. Total P Flux vs. Sub-basin Net P Balance

22. Lower Mississippi Sub-basin – USGS note
• “Average annual net nutrient fluxes for the Lower Mississippi
and Upper Mississippi subbasins are calculated as a
difference between fluxes from two or more stations, which
results in larger errors compared to the error for the other
three subbasins for which nutrient fluxes are either estimated
from an individual station or as the sum of fluxes from
multiple stations. These larger errors occur because the
resulting net nutrient fluxes are small differences between
much larger numbers and by the rules for calculating
confidence intervals for differences. The Lower Mississippi
subbasin has the largest confidence intervals because net
fluxes are calculated as a combination of flux estimates from
six stations and because the resulting net fluxes are small
compared to the component fluxes. The Lower Mississippi is
the smallest subbasin, accounting for only 5.8 percent of the
total drainage area of the MARB.”
http://toxics.usgs.gov/pubs/of-2007-1080/discussion_5large_basins.html

23. Illinois River Nitrate-Nitrogen Concentrations
and Loads: Long-term Variation and Association
with Watershed Nitrogen Inputs.
• “… statistically significant association between annual
flow-weighted nitrate-N concentration and cumulative
residual agricultural N inputs to the watershed during a
6-yr window.”
• “… declines in flow-weighted nitrate-N concentration
may reflect increasing N use efficiency in agriculture and
a depletion of legacy N stored in the watershed.”
• “…. relatively constant N fertilization rates combined
with steadily increasing corn yields have improved
N use efficiency and likely contributed to the nitrate-
N concentration declining in the Illinois River”
Gregory F. McIsaac, Mark B. David, and George Z. Gertner. 2016. J. Environ. Qual. 45:1268-1275

24. River Flow Differs Among Sub-basins

25. River Flow Differs Among Sub-basins

26. U.S. Yield Trends of Major Cereal Grains
Source: USDA NASS data
0
20
40
60
80
100
120
140
160
180
1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020
Yield,bu/A
Year
corn
rice
wheat

27. Future Plans
• Continue these analyses as the NuGIS
database is populated with more annual
data
• Work with agribusiness, university,
government, and conservation partners:
– to advance 4R Nutrient Stewardship
implementation and actions to increase crop
yields and in-field nutrient retention
– Ensure 4Rs are part of cropping system and
complement soil and water conservation
• Monitor trends in nutrient use and
management metrics
• Encourage documentation and tracking of
nutrient performance by farmers on
individual fields and farms