Soil Test Levels in North America, 2010

Paul E. FixenSr. Vice Presidentpfixen@ipni.net

IPNI Webinar: January 26, 2011

IPNI: a not-for-profit, science-based, global organization dedicated to the responsible management of plant nutrition

Supported by leading fertilizer manufacturers and industry associations

Our soil resource

USDA, 2005.

63 private and public soil testing

laboratories4.4 million samples

P, K, pH, Mg, S, Zn, Cl

Summary results: http://info.ipni.net/soiltestsummary• Downloadable summary article (BC)• Order form for 42 page bulletin• CD – pdfs, ppts, spreadsheets

Private Laboratories

A&L Analytical Labs, Inc. - Memphis, TNA&L Canada Laboratories, Inc. - London, ONA&L Eastern - Richmond, VAA&L Great Lakes Labs, Inc. - Fort Wayne, INAgri-Food Laboratories, Guelph, ONAgriQuanta - St-Ours, QCAGVISE Laboratories - Northwood, NDALS - Calgary, ABBrookside Lab, Inc. - New Knoxville, OHDellavalle Laboratory, Inc. - Fresno, CAFrontier Labs - Clear Lake, IALaboratoire Géosol - Mont St-Hilaire, QCGMS Laboratories - Cropsey, ILLa Coop fédérée - Longueuil, QCLGI - Ellsworth, IALitchfield Analytical Services - Litchfield, MI

MDS Harris - Lincoln, NEMidwest Laboratories, Inc. - Omaha, NEOlsen’s Ag Lab - McCook, NEPrecision Agri-Lab - Madera, CARock River Lab - Watertown, WIServi-Tech, Inc. - Amarillo, TXServi-Tech, Inc. - Dodge City, KSServi-Tech, Inc. - Hastings, NESGS Alvey Laboratory, Inc. - Belleville, ILSGS MWSS, Inc. - Brookings, SDSpectrum Analytic, Inc. -Washington Court House, OHSURE-TECH Laboratories - Indianapolis, INWard Laboratories, Inc. - Kearney, NEWestern Laboratories - Parma, IDWilliam Houde, Ltd. - St-Simon, QC

Public Laboratories

Auburn UniversityClemson UniversityColorado State UniversityDepartment of Natural Resources Corner Brook, NLIowa State UniversityKansas State UniversityKentucky Division of Regulatory ServicesMichigan State UniversityMississippi State UniversityNew Brunswick Agriculture and AquacultureNew Mexico State UniversityNorth Carolina Department of AgNorth Dakota State UniversityNova Scotia Department of AgricultureOklahoma State University

PEI Soil & Feed Testing LaboratorySouth Dakota State UniversityTexas A&M UniversityThe Pennsylvania State UniversityUniversity of ArkansasUniversity of ConnecticutUniversity of DelawareUniversity of FloridaUniversity of GeorgiaUniversity of GuelphUniversity of MaineUniversity of MissouriUniversity of New HampshireUniversity of TennesseeUniversity of VermontUniversity of WyomingVirginia Tech

Figure 1. Soil sample volume in the U.S., 1949-2010.

Some cautions in interpreting the summary

• Several states and provinces have low sample volumes, reducing the reliability of summary statistics.

• Better managers likely test more frequently and their results may not be representative of those that do not soil test.

• The requirement of nutrient management plans for many livestock operations may have increased the portion of samples from manured fields compared to the past in some regions and inflated soil test levels, especially for P.

• Error was likely introduced in defining calibration equivalency for each of the soil test categories among the various testing procedures.

• Some laboratory data were submitted using categories other than those specified in the sampling protocol, and interpolation routines were created and used to translate between the two systems.

Figure 6. Soil test P frequency distribution

in 2001, 2005, and 2010.

Variability in state P distributions

0

10

20

30

40

50

5 10 15 20 25 30 35 40 45 50 >50

Rela

tive,

%

Bray P1 equivalent, ppm

North Dakota

2001 38,450

2005 66,887

2010 75,279

0

5

10

15

20

5 10 15 20 25 30 35 40 45 50 >50

Rela

tive,

%

Bray P1 equivalent, ppm

Iowa2001 380,265

2005 355,983

2010 775,401

05

101520253035

5 10 15 20 25 30 35 40 45 50 >50

Rela

tive,

%

Bray P1 equivalent, ppm

California2001 24,704

2005 22,707

2010 36,192

0

20

40

60

80

100

5 10 15 20 25 30 35 40 45 50 >50

Rela

tive,

%

Bray P1 equivalent, ppm

Delaware

2001 1,666

2005 5,677

2010 10,854

28% >200 ppm

Figure 5. Median Bray P-1 equivalent soil test levels, 2010.

Figure 2. Critical Bray P1 equivalent soil test levels, 2010.

Figure 7. Percent of samples testing below critical levels for P for major crops in 2010.

Figure 8. Change in median Bray P equivalent soil test levels from 2005 to 2010.

Soil test P distribution in 2010 compared to 2005 for the Corn Belt (12 states plus Ontario)

0%

5%

10%

15%

20%

25%

30%

Bray P1 Equivalent, ppm

Corn Belt P 2005 2.0 million samples2010 3.0 million samples

(2010) 22 28 (2005)Median

• Available on line: http://www.ipni.net/nugis

– Printed bulletin– Interactive features

2010 median soil P levels* and change from 2005(Soil samples, millions: 2005=2.0; 2010=3.0)

ND

SD

MN

PAOHINIL

IA

WIMI

NE

KSMO

KY

WVV

NC

ON

*Median Bray P1 equivalent, ppm

13-1

26-3

16-2

22-3

26-10

41-626

-13

18-3

18-4

180

24-1

42-7

180

Annual change in median soil P level for 12 Corn Belt states as related to state P balance, 2005-2009.

*NuGIS is a GIS nutrient balance model (IPNI, 2010).

y = 0.0897x - 0.063r² = 0.62

-3.0

-2.5

-2.0

-1.5

-1.0

-0.5

0.0

0.5

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

Annu

al ch

ange

in m

edia

n P,

ppm

NuGIS balance*, lb P2O5/A/yr

A balanced budget gives no net change in soil P

WI

IL

MI

IA

MNSD

KS

OHIN

NE

KY

MO

Figure 11. Soil test K frequency distribution in 2001, 2005 and 2010.

Variability in state K distribution

0102030405060

40 80 120 160 200 240 280 320 >320

Rela

tive,

%

Ammonium Ac Equivalent K, ppm

Georgia

2001 76,660

2005 144,773

2010 67,219

0

5

10

15

20

25

30

40 80 120 160 200 240 280 320 >320

Rela

tive,

%

Ammonium Ac Equivalent K, ppm

Iowa 2001 327,457

2005 366,178

2010 720,353

0

10

20

30

40

50

40 80 120 160 200 240 280 320 >320

Rela

tive,

%

Ammonium Ac Equivalent K, ppm

South Dakota2001 17,806

2005 33,730

2010 67,426

010203040506070

40 80 120 160 200 240 280 320 >320

Rela

tive,

%

Ammonium Ac Equivalent K, ppm

Nebraska

2001 143,761

2005 189,132

2010 318,665

Figure 10. Median soil test K levels in 2010.

Figure 3. Critical ammonium acetate equivalent soil K levels, 2010.

Figure 12. Percent of samples testing below critical levels for K for major crops in 2010.

Figure 13. Change in median soil K level from 2005 to 2010.

Figure 14. Median soil pH in 2010 and change from 2005.

Figure 16. Percent of samples testing < 3 ppm S in 2010.

(4% in 2005)

Figure 17. Percent of samples testing < 1.0 ppm DTPA equivalent Zn in 2010.

16% < 0.5 ppm

Figure 18. Percent of samples testing <4 ppm Cl-.

Summary of the 2010 Findings• Approximately 4.4 million samples from 63 laboratories are

included in the 2010 summary.• Collectively, the 2005 and 2010 summaries examine nearly 8

million samples to provide a view of soil fertility trends in North America.

• Submissions indicate use of soil testing has increased substantially since 2005.

• Results indicate: – the extreme variability of fertility levels – more soils than ever are at or below critical levels– and that the levels do indeed change over time.

Summary (continued)

• Median P level is 25 ppm, a 6 ppm decline from 2005, with soil P declines in the Corn Belt correlated with partial P balances.

• Median K level is 150 ppm, a 4 ppm decline from 2005 and close to what many recommendation systems consider to be a critical level.

• Mg: levels are generally lowest in the Southeast but with a significant occurrence of lower levels in the Northeast.

• S: frequency of samples testing low in S has increased since 2005. • Zn: 37% of samples test <1 ppm and 16% test <0.5 ppm,

indicating that many soils in NA should be responsive to Zn fertilization.

• Cl: Northern Great Plains has a high frequency of soils low in Cl-.• Median pH for U.S. and Canada is 6.4 compared to 6.3 in 2005.

Soil testing today is more important than ever across NA …

a critical component of 4R Nutrient Stewardship