MUHAMMAD FAHAD ANSARI MUHAMMAD FAHAD ANSARI 12IEEM 1412IEEM 14

Characteristics & efficient Use of fertilizers

CharacteristiCharacteristics & cs &

efficient Use efficient Use of fertilizersof fertilizers

Potash & Phosphate Institute/Potash & Phosphate Institute of Canada

Fertilizer Use Efficiency:Fertilizer Use Efficiency: An Old Topic but With New ImportanceAn Old Topic but With New Importance

International Nitrogen Initiative (INI) Goal: to optimize N’s beneficial role in sustainable food

production and minimize N’s negative effects on human health and the environment resulting from food and energy production.

Will focus attention on improving fertilizer N efficiency at a global scale

Multiple Level Nutrient Management NRCS program under development to subsidize farmer

practices that improve nutrient use efficiency Will test our collective understanding of nutrient use efficiency

for N and P

Traditional Nutrient Efficiency TermsTraditional Nutrient Efficiency Terms

Recovery efficiency (RE) = Increase in uptake per unit nutrient added usually expressed as %

Agronomic efficiency (AE) = Crop yield increase per unit nutrient added such as bu/lb or kg grain/kg nutrient

30354045505560657075

1960 1965 1970 1975 1980 1985 1990 1995 2000

Kg

grai

n pe

r kg

N .

Agronomic efficiencyAgronomic efficiency of fertilizer N used of fertilizer N used on corn grain in the U.S., 1964-2002 on corn grain in the U.S., 1964-2002

4343

5959

39% increase in N efficiency12% increase in fertilizer N per ha

40% increase in corn yieldsSince 1975:

N fertilizer N fertilizer recovery efficiencyrecovery efficiency using using on-farm measurementson-farm measurements

Opportunity for improvementOpportunity for improvement

Crop Region Number of farms

Avg N rate, kg/ha

Recovery, %

Maize NC USA 56 103 37

Rice Asia-farmer Asia-researcher

179

179

117 112

31 40

Wheat India-poor weather India-good weather

23 21

145 123

18 49

Cassman et al., 2002

Areas of opportunity for improvement Areas of opportunity for improvement in fertilizer N efficiencyin fertilizer N efficiency

Continued improvement in cropping system management Realistic estimation of attainable yield Yield potential protection – pest management

and other cultural practices Balanced nutrition

Ohio State University – dryland corn 80 ppm soil test K80 ppm soil test K 45% N recovery45% N recovery 139 ppm soil test K139 ppm soil test K 80% N recovery80% N recovery

Kansas State University – irrigated corn No P appliedNo P applied 35% N recovery35% N recovery 45 kg ha45 kg ha-1-1 75% N recovery75% N recovery

Balanced nutrition in the U.S.Balanced nutrition in the U.S.

Balanced nutrition in ChinaBalanced nutrition in China

TreatmentTreatment

ReferenceReference CropCrop NN NPKNPK

N recovery by crop,%

Zhu, 1994 Barley 2828 5151

Jin, 2001 Wheat (11 yrs) 3131 7070

Corn (5 yrs) 3535 6666

Areas of opportunity for improvement Areas of opportunity for improvement in fertilizer N efficiencyin fertilizer N efficiency

Continued improvement in cropping system management

Use of site-specific precision ag technologies

Site Specific Management:Site Specific Management:Accounting for spatial variabilityAccounting for spatial variability

Spatial variability in fertilizer N efficiencySpatial variability in fertilizer N efficiency

28-39

39-50

50-62

62-73

N Efficiency,kg grain/kg N

Year 1Uniform N rate

11.1 t/ha average yield

Year 3Variable N rate

11.3 t/ha average yield

SoybeansIn year 2

Indiana; twoN rates based

on soil type

Murrell and Murrell, 2002

Variable N rate contributed to increased N Variable N rate contributed to increased N efficiencyefficiency

1

8

1

0

2 2

4

2

0

1

2

3

4

5

6

7

8

9

28-39 39-50 50-62 62-73

N use efficiency, kg grain/kg applied N

Fre

qu

en

cy o

f zo

nes

Whole field year 1, 47 kg grain/kg N

Variable rate year 3, 53 kg grain/kg N

40 ha field divided into 10 zones40 ha field divided into 10 zones

13% increase infertilizer N efficiency

Murrell and Murrell, 2002

Areas of opportunity for improvement Areas of opportunity for improvement in fertilizer N efficiencyin fertilizer N efficiency

Continued improvement in cropping system management

Use of site-specific precision ag technologies Better prediction of soil N mineralization Improved timing of N application Improved manure management and crediting Improved fertilizers Biotechnology?

Is the concept of fertilizer use Is the concept of fertilizer use efficiency the same for P and K as it efficiency the same for P and K as it

is with N?is with N?

5 10 15 20 25

Bray P-1, ppm

0

20

40

60

80

100

120

P u

se e

ffic

ien

cy, k

g c

orn

/kg

P

The result of applying the definition of The result of applying the definition of

agronomic efficiency for N to P agronomic efficiency for N to P The highest “efficiency” occurs when inadequate amounts

are applied at low soil test levels Building soil test levels to optimum reduces “efficiency” “Efficient” P use means reduced profitability, water use

efficiency, N use efficiency, and land use efficiency

LowLow HighHigh

*

*

**

**

We need to view P and K efficiency We need to view P and K efficiency as different than N efficiencyas different than N efficiency

A.E. Johnston and P Poulton“The difference method (RE) is appropriate for N … but

is less useful for P and K where plant available reserves of these nutrients can accumulate in the soil from past applications of fertilizer.”

Sustainable efficiency (for P&K) – Nutrient input needed to sustain the system at optimum productivity expressed as a removal to use ratio

P and K Sustainable Efficiency in N. AmericaP and K Sustainable Efficiency in N. America

Review current crop removal to use ratios Review current soil test levels Combine the two to assess efficiency

Information Sources: • Soil Test Levels in North America, PPI/PPIC/FAR Technical Bulletin 2001-1.• Plant Nutrient Use in North American Agriculture, PPI/PPIC/FAR Technical Bulletin 2002-1.

Partial K budgets for the U.S. Partial K budgets for the U.S. (average of 1998-2000)(average of 1998-2000)

Crop Applied Recov. Removal to use

Region removal fertilizer manure* fertilizer fert+man

------- K2O, billion kg ------

U.S. 8.8 4.6 1.7 1.91 1.39

6 corn states 3.0 1.9 0.5 1.62 1.30

* USDA-NRCS, 2000; Due to manure distribution problems relative to crop demand,this likely overestimates the agronomic contribution.

Ratio of K removal by crops to fertilizer Ratio of K removal by crops to fertilizer applied plus recoverable manure applied plus recoverable manure

ND

SKMB

ON

BCAB

WA

OR

MT

ID

SD

MN

PQPQ

NY

PAOHOHININILIL

IA

WIWIMIMI

WY

UT

NV

CA

AZ NM

NBNB

NSNS

PEIPEI

ME

NH

VTVT

MAMACTCT

RIRI

NE

KSMO

KYKY

WVVAVA

MDMD

DEDE

NJNJ

NCNCTNTN

ARAROK

TX LALA

ALAL GAGA

SCSC

FLFL

CO

1.50-4.99

0.90-1.09

0.00-0.89

1.10-1.49

> 5.00

R/(F+M)

MSMS

Percent of Soils Testing Medium or Lower Percent of Soils Testing Medium or Lower in K in 2001in K in 2001

North AmericaNorth America43%

Partial P budgets for the U.S. Partial P budgets for the U.S. (average of 1998-2000)(average of 1998-2000)

Crop Applied Recov. Removal to use

Region removal fertilizer manure* fertilizer fert+man

------- P2O5, billion kg ------

U.S. 5.2 4.0 1.5 1.30 0.95

6 corn states 2.3 1.4 0.4 1.71 1.33

*USDA-NRCS, 2000; Due to manure distribution problems relative to crop demand and unavailability of a portion of manure P, this likely overestimates the agronomiccontribution.

Ratio of P removal by crops to fertilizer Ratio of P removal by crops to fertilizer applied plus recoverable manureapplied plus recoverable manure

ND

SKMB

ON

BCBCAB

WA

OR

MTMT

ID

SD

MN

PQPQ

NY

PAOHINIL

IA

WIMI

WY

UT

NV

CACA

AZ NM

NBNB

NSNS

PEIPEI

MEME

NH

VT

MAMA

CTCTRIRI

NE

KSMO

KY

WV

VAVA

MD

DEDE

NJNJ

NCNCTN

AROK

TX LA

MS ALAL GAGA

SCSC

FLFL

CO

1.10-1.49

0.50-0.89

0.00-0.49

0.90-1.09

>1.50

R/(F+M)

Percent of Soils Testing Medium or Lower Percent of Soils Testing Medium or Lower in P in 2001in P in 2001

North AmericaNorth America47%

Viewing removal to use in light of soil Viewing removal to use in light of soil test levelstest levels

Large regional differences exist across North America in both current removal to use ratios and soil test levels

“1” is often not the appropriate removal to use ratio target for a state or for a field Soil test levels < optimum: ratio should be < 1 Soil test levels > optimum: ratio should probably be > 1

Starter fertilizer needs are often independent of soil test levels or removal to use ratios

Low and decreasing

High but decreasing

Low and increasing High and increasing

State level P assessment: R/(F+M)State level P assessment: R/(F+M)E

st.

cro

p r

em

ov

al

/ (f

ert

iliz

er

+ m

an

ure

us

e)

State median soil test level - target level, ppm

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

-15 -10 -5 0 5 10 15 20 25

Target level = lower end of high category

AR

GA

SD

WI

IA

Estimating target removal/use ratio for a fieldEstimating target removal/use ratio for a field

Target K test = 150 ppm Current test = 130 Build: (150 - 130) x 9 kg K2O/ppm = 180 kg K2O/ha

To spread build over 4 yrs = 180/4 = 45 kg K2O/ha

Avg crop removal per year = 67 kg K2O/ha

Total to apply = 45 + 67 = 112 kg K2O/ha

Target removal to use ratio = 67/112 = 0.60

Examples of apparent recovery efficiency Examples of apparent recovery efficiency of P fertilizer in long term studiesof P fertilizer in long term studies

Soil(s) Applied No. of Recovery

P2O5, kg/ha Crops %

Calcareous clay 67 5 F 28

Clay loam, pH 7.3 29 9 F 54

28 soils, pH 6.2-7.9 152 8 GH 74

4 soils, pH 6.7-7.6 230 19 GH 87

Sandy loam, non-calcareous 118 4 F 100

GH = Green house; F = Field.GH = Green house; F = Field.

Fixen, 1992

If a field is at its optimum soil test If a field is at its optimum soil test level, and replacement of the P and level, and replacement of the P and K removed by crops maintains that K removed by crops maintains that

optimum level, what is the efficiency optimum level, what is the efficiency of P or K? of P or K?

100%100%If use must exceed removal to maintain optimum productivity,soil erosion or fixation are often the cause: Reduce erosion losses Utilize banding and annual fertilizer application

Impact of Improving Efficiency on Impact of Improving Efficiency on Fertilizer DemandFertilizer Demand

Critical to properly define efficiency for the nutrient in question

Nitrogen Good progress has been made in improving

agronomic efficiency Will be significant pressure to further improve

agronomic efficiency without sacrificing yield potential Research shows there is room for improvement Yields will likely continue to increase faster than N

use

Impact of Improving Efficiency on Impact of Improving Efficiency on Fertilizer Demand (continued)Fertilizer Demand (continued)

Phosphorus and potassium Will be increasing pressure to improve system efficiency by

reducing P levels where excessive Sustainable efficiency will translate into increased P and K

demand in some major production regions Pressure to improve N efficiency should result in increased

support for balanced nutrition with P and K Higher future crop yields could require higher target soil

test levels and temporarily impact demand The thermodynamic need to replace P and K removal at

some soil level sets a lower limit for P and K use As food needs increase … fundamentals of

natural systems indicate a permanent and expanding role for fertilizers in food production