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How to Improve Nitrogen Use Efficiency - North America

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Pennsylvania Agronomic Education Conference
University Park, PA
16 January 2008
How to Improve Nitrogen
Use Efficiency
Tom Bruulsema, PhD, CCA
Director, Northeast Region, North America Program
IPNI Mission
“to develop and promote scientific information about plant
nutrient management for the benefit of the human family.”
NUE
1.Defining
2.Tracking
3.Improving
Definitions of NUE
• Partial Factor Productivity (PFP)
– Grain harvested per unit of N applied
– 40-80 units of grain per unit of N
• Agronomic Efficiency (AEN)
– Increase in grain harvested per unit of N applied
– 10-30 units of grain per unit of N
• Partial nutrient balance (PNB)
– N removed in grain as % of N applied
– Often 80% or more
• Apparent Recovery Efficiency (REN)
– Increase in N taken up into plant as % of N applied
– 30-50% typical; 50-80% with BMPs
Example – Irrigated Corn
N rate, Yield,
lb/A
bu/A
PFP,
lb/lb
AE,
lb/lb
Net
return
RE, %
to N,
$/A
PNB,
%
0
120
-
-
-
-
-
90
143
89
14
100
36
45
120
147
69
13
78
33
47
150
149
56
11
64
30
43
NUE: optimize versus maximize
Calculated from Shapiro and Wortmann, 2006. Agron. J. 98:529–535
Partial Factor Productivity
(PFP) Trend for N Fertilizer
Use on Corn, USA
PFP, grain per unit of N
80
70
60
50
40
30
1964
1971
1978
1985
1992
1999
2006
Year
Data source: USDA-NASS-ERS
Yield Goal – Moving Target
CORN YIELD TRENDS
160
YIELD
120
Bay Watershed
USA
80
40
0
1940
1962
1984
2006
YEAR
Why Improve
Nitrogen Use Efficiency?
• Economics
• Environmental impacts
– Nitrate in drinking water
– Eutrophication & hypoxia
– Biodiversity loss
– Smog and PM2.5 from ammonia emission
– Ozone depletion – N2O
– Greenhouse gases – N2O and CO2
New
Publication
Global Warming Potential
of Crop Production
GWP in CO2 equivalents
(kg/ha/yr)
Cropping system
Soil C
N
fertilizer
Mean Crop Yields
(t/ha)
N2O
Net
GWP
C
W
S
GWP/
Yield
kgCO2
/Gcal
Nebraska, irrigated
CC BMP
-1613
807
1173
1980
14.0
41
CC intensive
-2273
1210
2090
3080
15.0
60
Michigan, rainfed
C-S-W, CT
0
270
520
1140
5.3
3.2
2.1
95
C-S-W, NT
-1100
270
560
140
5.6
3.1
2.4
11
Organic
-290
0
560
410
3.3
1.6
2.7
46
-1170
50
100
-1050
Cropland
conversion to
forest
Robertson et al. (2000); Adviento-Borbe et al. (2007)
The “Myth” of N Fertilization for
Soil C Sequestration
(Khan, Mulvaney, Ellsworth and Boast. 2007.
J Environ Qual. 36:1821-1832.)
• Fertilizing at N rates higher than optimum for yield is unlikely to
increase soil C
• Many long-term studies show soil C is higher with optimal
compared to zero N
400
Carbon Stored, kg/ha/year
sawdust+N
300
200
sawdust
straw+N
100
straw
0
-100
crop+N
-200
crop
-300
fallow
-400
0
500
1000
1500
2000
2500
Carbon Input, kg/ha/year
Adapted from Paustian et al., 1992
Schulten and Schnitzer,1997
Average corn yields (1989-1993) and soil organic matter
levels for a Brookston clay loam soil under different
management practices since 1959.
Management
Continuous corn
Continuous corn
Rotation corn
Rotation corn
N-P2O5-K2O
(lb/A)
115115-7070-30
0-0-0
115115-7070-30
0-0-0
Yield
bu/A
104
13
145
65
SOM
%
3.6
3.1
4.4
3.3
Woodslee, Ontario, Gregorich & Drury, 1996
How to Improve NUE
• Genetics
• Manage for MEY
• Enhanced-efficiency fertilizer products
• Manage for weather
• Precision: technologies, application equipment
• On-farm research
New Hybrids prolong
N Uptake
Tollenaar, et al., 1997
Genetics
180
Yield, bu/A
new hybrid
120
old hybrid
60
0
0
50
100
150
200
N Applied, lb/A
A new hybrid yields more with less N, compared to one popular 20
years ago. Mean of 4 years’ data from Illinois (Below, 2007).
GM Genetics?
250
triple
Yield, bu/A
200
single
150
100
50
0
0
50
100
150
200
N Applied, lb/A
A “triple-stack” Bt-rootworm hybrid responds
differently than one with a single herbicide
resistance trait (2006 data; Below, 2007).
• Grow more on less land,
preserving natural
ecosystems
• Grow more with less impact;
minimize losses
• Apply principles of ecology
to increase cropping system
productivity
Manage for
Maximum Economic Yield
Balanced Fertilizer
Improves NUE
Hay Yield, ton/A
4
K150
K100
K50
K0
3
2
1
0
0
50
100
150
200
250
N Fertilizer, lb/A
Long-term Timothy, New Brunswick, Canada. Belanger & Richards, 1996
Enhanced efficiency
Fertilizers
1. Synthetic organic compounds containing N
Вѕ urea-formaldehydes, IBDU, triazines, etc.
2. Physical coating or barrier around soluble N fertilizer
Вѕ SCU, PCU, etc.
3. Stabilized materials
Вѕ nitrification and urease inhibitors
History of Slow-Release N
Year
%N
Product
1924
12-40 Urea-formaldehyde (European patent)
1955
12-40 Urea-formaldehyde (commercial use in USA)
1961
32-38 Sulfur-coated urea (TVA)
1960’s
32-34 Crotonylidene diurea (32-0-0)
1960’s
31
1967
9-19
1985
14-22 NutricoteВ®, MeisterВ®, ProkoteВ®, EscoteВ®
1990
37-44 PolyOnВ®
1990
10-42 MulticoteВ®
1990’s
Isobutylidene diurea (31-0-0; IBDU)
OsmocoteВ®
44
VCoteВ®, TR2В®, ESNВ®, DurationВ®
65
Dicyandiamide (DCD)
Adapted from Dr. James Robbins, University of Arkansas, 2005
Nitrification Inhibitors…
NH4+
-H+
+H+
NH3
Nitrosomonas
NO2-
Nitrobacter
NO3-
• Interfere with activity of Nitrosomonas bacteria
• Leave more N in ammoniacal form, thus reducing risk of
leaching and denitrification
Urease Inhibition…
urease
CO(NH2)2 + H+ + H2O
NH4+
2NH4+ + HCO3-
NH3 + H+
• Interfere with the process of
urea hydrolysis
• Slower conversion of urea to
ammoniacal N can reduce
NH3 volatilization
Catherine J. Watson, Queen’s University of Belfast
Enhanced efficiency
Fertilizers - Summary
• Potential benefits of EE fertilizers include
– More closely match nutrient release to plant demand
– Improved yields – more uniform plant growth
– More applied nutrient used by plant
– Reduction in nutrient loss (leaching, denitrification, volatilization)
– Fewer trips across the field
• Appropriate product is specific to soil and crop conditions
• Slower release cannot always be assumed a benefit
– Immediate availability of soluble fertilizers
New
Publication
New York
Model Infrastructure
MelkonianPNM
- NY
Daily
Precision
Northeast
update of
CTC
Regional
Nitrogen
(Cornell Theory
high
Center)
resolution
Climate
Manageclimate data
Data
Center
warehousing and
ment
manipulation
(NRCC)
High
(PNM)
resolution
• Rapid Update
Query
climate data
Model
Cycle (RUC)
model forecasts
(temperature data)
PNM Model
• Radar data for
determination of
precipitation fields
(precipitation data)
Temperature data: 5km x
5km grid) temperature data
sets in essentially real time.
Precipitation data: daily
gridded (4 km x 4 km)
precipitation fields (corrected
by gauge observations).
Model
output
Model
inputs
User
Interface
N
recommendation
Model
inputs
Stakeholders
• Farmers
• Consultants
Melkonian & van Es, Cornell University
Suggested adjustments to sidedress N rates: 6/30/06
Soil Texture
Climate Region
Fine
Medium
Coarse
1 East
+10
+10
+10
1 West
-10
-10
-10
2
+25
+25
+30
4
0
+10
+15
5&6
+25
+25
+30
7 North
+10
0
+10
7 South
+15
+20
+25
8
+10
+10
+15
9 East
0
0
0
9 West
-15
-15
-15
10 East
+10
+10
+10
10 West
-10
-15
-15
Melkonian & van Es, Cornell University
EONR on 3 soils within a 35-acre
field, over 5 years (Aurora, NY)
250
EONR (lb/A)
200
Honeoye-Lima (MWD)
Kendaia (SPD)
Lyons (PD)
150
100
50
0
1978
1979
1980
Year
1981
1982
Harold van Es, Cornell University
Precision Technology
• Precision application
– Controllers, guidance, autosteer
• Variable rate application
Ontario On-Farm Experience:
Response Trial Design
•
•
•
•
Field-length strips
Plant, apply N, and harvest with field equipment
Minimum six strips; rates assigned randomly
At least one check @ either zero N or <35 lb/A of N as
starter
• At least one treatment @ ≤ half “normal” rate
• At least one treatment @ ≥ 1.2 X “normal” rate
• Crop Nutrient Response Tool (Excel)
– http://www.ipni.net/CNRT
Why Assess NUE On-Farm?
1. Crop response to nutrients is site-specific
•
Local climate and soil
•
Weather
•
Producer management level
•
Interaction with genetics
Why Assess NUE On-Farm?
2. New opportunity to provide value
– Strengthen relationships with extension
– Develop customer loyalty
– Improve profitability & NUE
– Participate in programs that reward
environmental improvement
– Validate models of crop and environmental
response
Water Quality Trading
• The Crop Adviser’s Role
• Loading rate versus
application rate
• Appropriate models
• NUE targets?
• “Stacked” with GHG
credits?
Summary
• Nitrogen use efficiency & effectiveness should be
measured, managed and optimized applying ecological
principles to intensify cropping systems
• Improve NUE with genetics, MEY, EE products,
managing for weather, precision…
• Practices that improve NUE need on-farm research
and validation
www.ipni.net
Thank
You!
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