water resources and biofuels water quality april 2012
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TRANSCRIPT
Water Resources: Issues & Opportunities Water Quality
Hypoxia – What is it?
An area of low dissolved oxygen concentrations that cannot support marine life. Typically O2 < 2 ppm
Hypoxia – Why does it occur?
Algae bloom in freshwater Algae settle to bottom Algae decomposition consumes O2
Hypoxia – How large an area?
http://www.epa.gov/gmpo/pdf/2007-hypoxia-pred-web-5.pdf
Turner and Rabalais, 2007
x
X – size in 2008
Hypoxia – Is nutrient flux constant?
co.water.usgs.gov
Hypoxia – Nitrogen Source?
www.umces.edu/President/hypoxia.htm
20 – 25 lb/A
Hypoxia – Source of Phosphorus?
Look to the Future
40
50
60
70
80
90
100
1980 1985 1990 1995 2000 2005 2010 2015
Planted area: Corn, wheat, and soybeans
Million acres
Corn
Wheat
Soybeans
Source: USDA Agricultural Projections to 2016, February 2007.Economic Research Service, USDA.
USDA Agricultural Projections to 2016D. R. Keeney
Corn/Soybean and Perennial Nitrate-N Concentrations in Tile
Drain Tile drainage system U of MN - Lamberton
0
5
10
15
20
25
Corn/Bean Perennials
mg/LMidpointof range
Gyles Randall, 2003
D. R. Keeney
Tom Kaspar
Tom Kaspar
Rye after corn silage
Kaspar et al., JEQ 36:1503-1511
Cumulative annual nitrate-N load of drainage water for 2002-2005
40.4
81.1
47.250.8
11.2 11.1
19.8
34.433.9
23.0
0
10
20
30
40
50
60
70
80
90
2002 2003 2004 2005 Avg.
Ann
ual n
itrat
e-N
load
(kg/
ha)
ControlRye Cover Crop
Cropping System Impacts on Drainage Water Quality and Quantity
Dr. Matt Helmers, Dr. Xiaobo Zhou, and Carl Pederson
ISU South Reynoldson FarmBoone County, IAComparison of Biofuel Systems (COBS)Each of the 24 plots is 90 ft x 200 ft
Photo by T. SchultzAugust 2009
Tile Drainage Flow 2010
Tile Drainage Flow 2011
NO3-N Concentration 2010
NO3-N Concentration 2011
NO3-N Loss 2010
NO3-N Loss 2011
Iowa Daily Erosion Project
Estimates daily soil erosion, runoff and soil moisture for the state of Iowa Daily estimations since 2002 Published in Jan/Feb 2006 Journal of the
Soil and Water Conservation Society Served on the web at
http://wepp.mesonet.agron.iastate.edu Parameterizes WEPP erosion model with
radar rainfall, climate stations, and NRI
Simulated crops Eight scenarios based on ISU research
Rotation Tillage Residue Removal
Cover Crop Abbreviation
NRI NRI No No NRI
Corn/Soy Min-till No No CS-MT
Cont. Corn Min-till Yes No CC-MTRR
Corn/Soy No-till No No CS-NT
Cont. Corn No-till No No CC-NT
Cont. Corn No-till Yes No CC-NTRR
Cont. Corn No-till Yes Yes CC-NTRRCC
Switchgrass No-till Yes No Sw-NTRR
NEXRAD – Aug 22, 2007
Statewide mean precipitation: 1.56 in.
Switchgrass – NT, RR
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Cont. Corn – NT
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Corn/Soybean – NT
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Cont. Corn – NT, RR
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Cont. Corn – NT, RR, CC
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
NRI Projected Rotation
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Corn/Soy - MT
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Cont. Corn - MTRR
Sw-NTRRCC-NTCS-NTCC-NTRRCC-NTRRCCNRICS-MTCC-MTRR
Event Summary
Management 8/22/2007 Mean Loss (tons/acre)
8/22/2007 Mean Runoff (in)
Sw-NTRR 0.044 0.657
CC-NT 0.113 0.662
CS-NT 0.184 0.651
CC-NTRR 0.230 0.649
CC-NTRRCC 0.232 0.650
NRI 0.320 0.640
CS-MT 0.406 0.647
CC-MTRR 0.458 0.646
Cum
ulat
ive
surfa
ce ru
noff
(in a
cre-1
)
0
1
2
3
4
5
6
100% Row-crop10% Perennial Cover at Toe Slope10% Perennial Cover in Contour Strips20% Perennial Cover in Contour Strips
Date
Cum
ulat
ive
sedi
men
t exp
ort (
lb a
cre-1
)
0
5000
10000
15000
20000
100% Row-crop10% Perennial Cover at Toe Slope10% Perennial Cover in Contour Strips20% Perennial Cover in Contour Strips
Thoughts to Ponder
Corn grain ethanol N applications likely unchanged P applications likely unchanged Water quality impacts likely unchanged Cover crop management good for system
Thoughts to Ponder (II) Cellulosic - conversion of corn stalks
Likely greater water quality challenges than current ag systems
Opportunities with cover crops to improve WQ Sediment/Phosphorus issues increase
Cellulosic – conversion of perennials Favorable WQ opportunities
• Surface • Subsurface
