Download Phosphorus Use Efficiency in Production Agriculture

Phosphorus Use Efficiency
in Production Agriculture
Paul Fixen
2007 Fertilizer Outlook and Technology
Conference
Nov. 7, 2006
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Purpose: To help provide a
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for fertilizer nutrient use and to
scientifically address the
associated environmental issues
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A key challenge for agriculture
Annual
%
Parameter
Predicted increase in global demand for corn, rice, and
wheat from 1995 to 2025*
Kg/ha/yr**
1.56
Global rate of yield increase, 1966-2004:
Corn, 61
1.24
Rice, 54
1.36
Wheat, 41
1.42
* Rosegrant et al. (2002, Food Policy Research Institute) as modified by Cassman
(2006) to include 5% of global grain supply in 2025 used for production of biofuel
and bio-based industrial feedstocks.
** All rates of gain in cereal yields are decidedly linear over the past 40 yrs
(Cassman, 2006); proportional rates of gain are based on 2004 yields.
U.S. corn yields, 1964 to 2006
180
nic
e
g
s
Tran its
tra
IPM
160
Corn yield, bu/A
140
120
100
80
60
40
y = 1.836x - 3536.3
ons.
C
R2 = 0.84 crease in
llage
i
t
In
tion
a
z
i
l
i
fert
N
c
i
t
Gene ment
ove
r
p
ced
m
n
i
a
l
a
&b
g
n
i
t
tion
tes
a
z
l
i
i
l
i
o
t
S
of
fer
n
K
o
i
P
s
N
n
Expa tion
irriga
20
0
1960
43 years of 1.84 bu/A/yr
1965 1970
1975
1980 1985
1990 1995
Breaking this line while meeting environmental
expectations will be a huge challenge
Concept by Cassman, 2006
2000
2005
General reasons to be
interested in P efficiency
• Recoverable P is a scarce
natural resource
– Manufacturer
– Grower
– Consumer
Phosphate reserves
Cost/tonne, Fob
$40 mine $100
Years
U.S.
25
98
World
90
343
Stewart et al., 2005
• Potential environmental
(ASA P Monograph)
benefits to keeping P in
the field
• Direct economic value to the grower
– Increased yield
– Faster return on investment
– Lower optimum P rates in some situations
Major reason for interest in efficiency
is likely influenced by soil P level
Median Bray P1 equivalent, ppm
BC
AB
MB
SK
98
18 10
17
37 105
58
Short term
14 11
24
grower
47
18
32
25
14
39 49
economics
105
57
15
22 25
36 29 2552
16 21
18 36
21
26
110
Avoiding
P
18
24
ON
PQ
PEI
WA
NB
ME
MT
ND
NS
MN
OR
VT
ID
NY
WI
SD
MI
CT MA NH RI
WY
IA
PA
NE
NV
IL
IN
MD
UT
DE
WV
CO
CA
NJ
OH
VA
MO
KS
KY
AZ
25
NM
17
OK
3.4 million samples
AR
103 58
loss to water
80
NC
21
19 17
27 36 48
18 15
MS
TX
North America
31 ppm
TN
AL
SC
GA
LA
FL
59
2005
The appropriate definition of P
efficiency depends on the
intended use of the result
Yield increase
Agronomic efficiency
P applied
Fertilized uptake – check uptake
P applied
Removed by crop
P applied
Recovery efficiency
(Single yr or long-term)
Removal efficiency
One intended use: basis of incentive
payments in farm programs
• NRCS: Multiple level nutrient management
• Precursor to 3-tier CSP structure
• Objective: intensify nutrient management beyond
the minimums of Form 590
• 2002: Performance-based approach considered
– Calculating NUE as a basis for incentives?
– Considered:
• Recommended/Applied
• Removed/Applied (removal efficiency)
• Performance-based dropped in favor of practicebased
Efficiency vs. effectiveness:
a single-season crop response example
Greatest
Greatest effectiveness
effectiveness
Yield response
Lowest
Lowest
efficiency
efficiency
effectiveness
effectiveness
Greatest
Greatest efficiency
efficiency
Lowest
Lowest
Applied P
Typical objectives of nutrient use
• Provide economically optimum nourishment to crop
• Minimize nutrient loss from the field
• Contribute to system sustainability … soil fertility or other
soil quality components
Utilization efficiency is not enough … P use must be
effective in meeting the objectives of nutrient use
Can be highly efficient … and totally ineffective
(low P rate at a low soil P test)
(lb wheat/lb applied P)
Agronomic and recovery efficiency
decline as soil fertility increases
28% 1st yr
recovery
Where do we advise
growers to be?
Near 0% 1st
yr recovery
Garcia, 2002
1st yr recovery is a poor indicator of
long-term profitability
High efficiency is not enough
Olsen soil test
at end of 5-yr: 15 ppm
42
Amount broadcast
initially, lb P2O5/A
160
Wheat yield, bu/A
40
80
8 ppm
38
0
36
5 ppm
34
Highest P efficiency
(about 30% recovery ) …
but not effective
32
30
28
0
Wager et al., 1986
10
20
30
Annual seed-placed P2O5, lb/A
40
Fertilizer Phosphorus Efficiency
14 recovered/70 applied = 20%
VS
70 removed/70 applied = 100%
Typical values for
185 bu/A corn in
the Midwest
P removed
with harvest
70 lb P2O5/A
Fertilizer P
70 lb P2O5/A
P in crop
residue
30 lb P2O5/A
14 lb P2O5/A
86 lb P2O5/A
Soil P
Recovery efficiency:useful in short-term; Removal efficiency:
useful in long-term when combined with soil P change
System level efficiency
Nutrients recovered in the crop plus the
net change in available soil nutrients
Dobermann et al, 2005
(lb wheat/lb applied P)
Agronomic and recovery efficiency
decline as soil fertility increases
28% 1st yr
recovery
Near 0% 1st
yr recovery
Garcia, 2002
If replacing removed P
maintains soil P, system
efficiency is 100%
The value to the grower of practices
that improve P efficiency
Soil modification
Genetic
improvement
Placement
Impact on
effectiveness in
meeting grower
objectives
P sources
& coatings
Timing
General
cultural practices
Right rate, right time, right place
does not always result in the highest
“efficiency”, but should offer the
greatest effectiveness in
accomplishing grower objectives
• Optimizing profitability
• Minimizing nutrient loss
• Providing system sustainability
Recovery and removal
efficiencies for P
Area
Term
(years)
World
1
World
US
P NUE (%)
15-25
(recovery efficiency)
Many
50-90
(recovery efficiency)
Annual
87
(removal efficiency)
Source
& method
Smil, 2000;
survey
Smil, 2000;
survey*
PPI, 2002**;
partial budget
* A global literature review is underway by Syers, Johnston and Curtin; funded by
FAO, IFA, IMPHOS, PPI/PPIC, and TFI that will offer more detailed information.
** 0.35 lb P2O5/bu used for removal by corn.
Phosphorus use compared to crop removal
for a corn-soybean rotation (2 yrs)
(avg of 2004 & 2005)
120
Iowa
120
Illinois
100
100
80
80
80
M
60
40
F
60
lb P 2 O 5 /A
100
lb P 2 O 5 /A
lb P 2 O 5 /A
120
M
40
R
F
40
R
F
20
20
Removal 0
efficiency
0
0
168%
M
60
20
139%
Indiana
R
121%
F Fertilizer P consumption/A planted to principle crops in 2004 + 2005.
M Annual recoverable manure P for 1997 x 2 (NRCS, 2000).
R Crop removal for 2004 and 2005 corn and soybean yields.
P budget for the state of Illinois by
watershed
Median Bray P-1 level
for 2005 crop = 36 ppm
State total, million lbs P2O5
+ Applied fertilizer (2005)
613
+ Recoverable manure (1997) 77
- Crop removal (2005)
1,075
Net budget
-385
Removal efficiency
156%
Short-term vs long-term P efficiency
• Long-term P efficiency
– Generally high in North America
– Removal efficiency of 85-90%
– Long-term recovery efficiency in research
of 40-90%
• Short-term P efficiency
– Much lower than long-term efficiency
– Single-year recovery seldom higher than
20%; often less than 10%
Where short term recovery is
important
• Time value of money … always has some
importance
• Short land tenure
Percent of land in farms rented
or leased in 2002 in the U.S.
U.S. 28.4%
Where short term recovery is
important
• Time value of money … always has some
importance
• Short land tenure
• Limited operating capital and sub-optimal
soil test levels
Percent of soil samples requiring annual P
fertilization to avoid profit loss in most major crops
2005 Crop Year
Where short term recovery is
important
• Time value of money … always has some
importance
• Short land tenure
• Limited operating capital and sub-optimal
soil test levels
• Soils with severe P fixing potential
• Threat to water quality
Summary
• The value of practices that improve P efficiency is
dependent on impact on effectiveness in meeting
grower objectives
– Optimizing profitability
– Minimizing nutrient loss
– Providing system sustainability
• Long-term fertilizer P efficiency in North America is
usually high but short-term efficiency can be quite low
• Short-term efficiency is most important when:
– Land tenure is short or uncertain
– Operating capital is limited and soil test levels are
below optimum
– Soils have high P fixing potential
– Fields or field areas pose a threat to water quality
Phosphorus Use Efficiency
in Production Agriculture
2007 Fertilizer Outlook and Technology
Conference
Nov. 7, 2006