Importance of Soil TestingHailin ZhangDepartment of Plant and Soil Sciences

Precision Nutrient ManagementStrategiesGrid soil samplingApparent Electrical ConductivityYield monitor/mappingSensing techniques

Purposes of Soil SamplingMeasure the nutrient content or availability of the soilIdentify nutrient deficienciesPredict crop response to added nutrientsBuild a nutrient management plan

Soil Testing History1842 - Liebig stated his law of the minimum.1843 - Rothamsted Experimental Station established.1892 - Magruder Plots established in Stillwater, OK.1909 - E.A. Mitscherlich related plant growth to nutrients.1920s - Bray, Hester, Morgan, Spurway, and Troug developed the concept of labile versus total analysis.1940s & 50s - Use of fertilizers spur interest in soil testing as a management tool.1960s - Evolution of soil testing continues as technological advances allow for improvements in analysis, correlation, and interpretation.

Milestones in Soil and Plant AnalysispH Electrode 1932Flame Photometer 1940Bray 1945Olsen 1954P - Ascorbic Acid Determination 1962Atomic Absorption 1960ICP 1970sDTPA 1978PC Computer 1980Mehlich 3 1984

Soil and plant testsAnimal WasteWaterFeed and forage

OSU Cooperative Extension

Describe how to collect a representative litter sample in a house like this. See reference Sample Animal Manure for Analysis.

Directly Serving All Counties, in Oklahoma; Also serve state, tribal and federal agencies, consultants, researchers and students.

Number of Samples Analyzed Since 1986

Chart1

28094

24885

31091

24261

23771

26193

30860

29093

35650

29445

34376

31590

29079

31270

32510

39478

46019

42833

41848

52001

54784

56152

No. of Samples

Year

No. of Samples

Sheet1

YearNo. of Samples

198628094

198724885

198831091

198924261

199023771

199126193

199230860

199329093

199435650

199529445

199634376

199731590

199829079

199931270

200032510

200139478

200246019

200342833

200441848

200552001

200654784

200756152

Sheet1

No. of Samples

Year

No. of Samples

Sheet2

Sheet3

Soil Test Results of Oklahoma Cropland

pH7.5%25%48%19%8%Nitrate-N40%43%29%18%10%STP300 %71%16%9%4%STK350%8%36%20%37%

Soil Samples from One Producer

Lab ID Sample pH NO3-N (lbs/A) P (lbs/A) K (lbs/A) 51240866.94052101051241077303688251241185.21816272651241294.832173654

Variety Response to Soil pHCuster, Ok101, Jagalene, Jagger, 2174, AP502Cl, Ok102, 2137 LimedNot Limed

Ok 101

The state-of-the-art equipments;dedicated and well trained technicians;technical support;develop and validate methods; research to ensure accurate recommendations

QC/ QA Program in placeUse:Internal & ExternalCheck Samples

ProducerCounty ExtensionUSPS MailOSU Mailing ServicesSWFAL Login RoomReports Online

Scooping samples for extractionOne acre to 6 inch deep contains about 2 million lbs of soil

The greatest potentialfor error in soil testingis in taking the sample

Considerations for Soil sampling StrategiesLocate variability responsive to fertilizer and limeObtain a sample that accurately represents the area sampledBalance cost of sampling with the value of information

Recognize Field Nutrient VariabilityNitrate - Nitrogenlbs/acre 0-30 31-40 41-50 51-60 61-80 >80(Nitrate-N within a 75 x 75 plot)

20 cores are needed to make a representativecomposite sample in order to get reliable soil test results

Chart1

42

37

49

57

46

47

44

39.5

36.5

42.5

47

45

45.7

45.6

43

42.8

45

45.2

44.4

44.2

44.8

45

44.8

44.5

Number of Samplesin a Composite

Nitrate-N (lb/A)

Sheet1

Number of SamplesNitrate-N (lb/A)

242

337

449

557

646

747

844

939.5

1036.5

1142.5

1247

1345

1445.7

1545.6

1643

1742.8

1845

1945.2

2044.4

2144.2

2244.8

2345

2444.8

2544.5

Sheet1

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Number of Samples

Nitrate-N (lb/A)

Sheet2

Sheet3

Soil Sampling StrategiesWhole field composites: Composite sample representing the average nutrient status of the field **************

55350261224DepthP (ppm)P Changes with Depth (no-till)31

Soil Probe

Get a Representative Sample

Clean Bucket

Right Depth

15-20 cores

Obtain the correct tool for soil sampling. The best tool is a soil probe or auger with depth marks. A clean plastic bucket is also needed for holding soil cores and mixing before putting in sample bags. Check with your county extension office if you need to borrow one.

Make up a composite sample from the sampling area. The composite is made up of from 15 to 20 cores from the area to be sampled. When sampling with a probe, simply push the probe to the specified depth as close as possible, 6-inch depth has been used in Oklahoma for crop nutrient recommendation.

Soil Sampling Strategies2. Zone composites: Break field based on known or expected source of variability

Soil Sampling Strategies3. Grid Sampling: Break field based on ordered patternGrid cell method: similar to whole fieldGrid center methodPoint sampling*******************

Field Soil Sampling, Soil Testing, and Making Fertilizer Recommendations Exercise 1. Random sampling of the entire field , 25 cores of soil from a 0-6 depth filling two soil sample bags from the composite mixture 2. Grid-cell sampling 15 cores of soil from a 0-6 depth 3. High resolution 15 cores of soil from a 0-6 depth

XXXXXXXXXXXXXWhole field1 acre gridSub-gridCenter areaPointXXXXXXXXXXXXXXXXXXXXXXX********

Whole fieldsample pH:

Team 1: 6.0, 6.1 Team 2: 6.4, 6.4

Chart3

117145111

140140179

221267250

195184203

1227945

1239876

8071104

452933

802817

748686

805752

573022

564747

884170

117119113

163184240

9211480

908761

6481101

333836

373140

544557

853953

656665

94.916666666787.7589.2083333333

Random Area

Center Area

Center Point

Cell Number

Soil Test P (pp2m)

Comparison of methods for sampling soil from 24 1-acre cells of a cultivated field, on soil STP.

Sheet1

Whole Field Soil Sampling

Lab 1Random 15.87.214109157

Lab 1Random 25.87.215105158

Lab 2Random 15.77.11898150

Lab 2Random 25.77.018100151

1-Acre Cell Sampling

Soil, Water & Forage Analytical LaboratorySamplepHBINO3-NPKSamplepHBINO3-NPKSamplepHBINO3-NPK

Soils Class Sample Data and Statistics1-a7.2361171621-ca6.7211451741-p7.343111158

Samples logged in on 11/7/022-a5.57.1221401552-ca5.97.2151401442-p5.67.117179144

Dr. Johnson3-a6.6192211723-ca6.7212672123-p6.714250190

4-a6.2111951474-ca5.67.0131841334-p5.67.115203133

pHBIT_No3PK5-a6.3211221595-ca6.512791455-p6.41145149

Count1271111271271276-a6.07.2231231326-ca6.17.222981446-p6.31776145

Average5.77.016801357-a5.77.123801217-ca5.67.134711147-p5.67.032104148

Min4.80000019076.70422708-a5.47.01445988-ca5.67.01429978-p5.77.11233122

Max7.30000019077.20582672289-a5.67.113801089-ca5.57.012281089-p5.77 717147

Median5.59999990467146813310-a5.77.1127411410-ca5.56.9118611510-p5.07.05886123

Mode5.30000019077144514411-a6.2218013811-ca5.37.0185711811-p5.26.81152120

12-a5.57.1135713812-ca5.37.0113011712-p5.37.0722124

SOIL ROUTINE TEST SUMMARY13-a5.37.1235612213-ca5.27.0204710713-p5.16.91247119

14-a6.07.2228814714-ca5.37.116419714-p5.17.01470121

pH7.5Total15-a6.17.21411720415-ca6.17.21511917615-p6.07.112113189

Count51746312716-a6.32216319516-ca6.22018422816-p6.515240227

Percent37.01%58.27%4.72%.%17-a5.77.1219214317-ca5.87.22011415517-p6.07.21880179

NO34018-a5.87.1139014418-ca5.46.9238714018-p5.77.11461174

Count267923612719-a5.67.0166415019-ca5.37.1198111019-p5.36.816101139

Percent18.11%62.20%18.11%1.57%20-a5.47.0213312820-ca5.77.193813620-p5.76.9836165

P30021-a5.47.0183715021-ca5.46.9163114621-p5.47.01140190

Count67541601273026262511/7/025.77 71714722-a5.97.1115415022-ca6.07.144515222-p6.2457160

Percent44.88%42.52%12.60%.%23-a5.47.0138513523-ca5.27.0173912123-p5.06.93653109

K35024-a5.37.1266512324-ca5.17.0356613124-p5.37.11365111

Count558300127Ave5.87.118.794.9143.1Ave5.77.017.487.8138.3Ave5.77.017.889.2149.4

Percent34.65%65.35%.%.%Stdev0.50.15.947.824.7Stdev0.50.17.060.633.2Stdev0.60.112.665.530.2

CV8.01.031.750.317.3CV8.31.440.169.024.0CV10.31.670.973.420.2

LabIDCustCodeSampleClass IDSamplepHBIPK

302617950111-p7.3431111581

302618950422-p5.67.1171791442

302620950733-p6.7142501903

3026219501044-p5.67.1152031334

3026229501355-p6.411451495High Resolution Sampling of 1-acre Cell 8

3026239501666-p6.317761456SamplepHBINO3-NPKSamplepHBINO3-NPK

3026249501977-p5.67.03210414871-a5.97.116821572-p6.07.1945129

3026259502288-p5.77.1123312282-a5.87.118801391-p5.97.11455162

3026269502599-p5.77 71714793-a6.06.98751453-p6.07.0679167

302627950281010-p5.07.05886123104-a5.87.012791454-p6.07.0868149

302628950311111-p5.26.81152120115-a5.47.017781045-p5.36.91272113

302630950341212-p5.37.0722124126-a6.07.214891606-p5.97.01253171

302631950371313-p5.16.91247119137-a5.87.014681447-p5.86.91368184

302632950401414-p5.17.01470121148-a5.77.113811488-p6.07.11090151

302633950431515-p6.07.112113189159-a5.67.011451199-p5.56.91056129

302634950461616-p6.5152402271610-a5.57.1135410410-p5.37.02844107

302635950491717-p6.07.218801791711-a6.07.287612311-p6.07.110102143

302636950521818-p5.77.114611741812-a5.67.0147311312-p5.37.01765130

302637950551919-p5.36.8161011391913-a5.57.195610313-p5.47.01260116

302638950582020-p5.76.98361652014-a5.36.9134710114-p5.37.01341110

302640950612121-p5.47.011401902115-a5.36.965010515-p5.37.1749111

302641950642222-p6.24571602216-a5.97.01410014216-p6.07.210150164

302642950672323-p5.06.936531092317-a5.77.1186711417-p5.77.2957119

302643950702424-p5.37.113651112418-a5.46.915499718-p5.77.1769111

Ave5.77.017.889.2149.4ave19-a5.06.79378319-p5.16.954687

Stdev0.60.112.665.530.220-a4.96.99488820-p4.97.094085

CV10.31.670.973.420.221-a5.87.2169813921-p5.67.21355100

30264495021011-ca6.72114517422-a5.57.0204812822-p5.47.12557120

30264595051022-ca5.97.21514014423-a5.26.8143811423-p5.07.0284198

30264695081033-ca6.72126721224-a5.07.011297524-p4.87.092573

302647950111044-ca5.67.01318413325-a4.97.08458725-p5.07.073770

302648950141055-ca6.51279145Ave5.57.115.086.2136.7Ave5.57.012.161.0124.0

302650950171066-ca6.17.22298144Stdev0.40.14.327.028.1Stdev0.40.16.325.231.1

302651950201077-ca5.67.13471114CV6.61.428.631.420.5CV7.11.351.741.425.1

302652950231088-ca5.67.0142997

302653950261099-ca5.57.01228108SamplepHBINO3-NPK

3026549502911010-ca5.56.91186115CIDD19-85.07.074390

3026559503211111-ca5.37.01857118CIDD18-85.17.01862114

3026569503511212-ca5.37.01130117

3026579503811313-ca5.27.02047107

3026589504111414-ca5.37.1164197

3026609504411515-ca6.17.215119176

3026619504711616-ca6.220184228

3026629505011717-ca5.87.220114155

3026639505311818-ca5.46.92387140

3026649505611919-ca5.37.11981110

3026659505912020-ca5.77.1938136

3026669506212121-ca5.46.91631146

3026679506512222-ca6.07.1445152

3026689506812323-ca5.27.01739121

3026709507112424-ca5.17.03566131

Ave5.77.017.487.8138.3

Stdev0.50.17.060.633.2

CV8.31.440.169.024.0

30267195032011-a7.236117162

30267295062022-a5.57.122140155

30267395092033-a6.619221172

302674950122044-a6.211195147

302675950152055-a6.321122159

302676950182066-a6.07.223123132

302677950212077-a5.77.12380121

302678950242088-a5.47.0144598

302680950272099-a5.67.11380108

3026819503021010-a5.77.11274114

3026829503321111-a6.22180138

3026839503621212-a5.57.11357138

3026849503921313-a5.37.12356122

3026859504221414-a6.07.22288147

3026869504521515-a6.17.214117204

3026879504821616-a6.322163195

3026889505121717-a5.77.12192143

3026909505421818-a5.87.11390144

3026919505721919-a5.67.01664150

3026929506022020-a5.47.02133128

3026939506322121-a5.47.01837150

3026949506622222-a5.97.11154150

3026959506922323-a5.47.01385135

3026969507222424-a5.37.12665123

AveAve5.87.118.794.9143.1

StdevStdev0.50.15.947.824.7

CVCV8.01.031.750.317.3

30269795075302hr-2-p6.07.19451291

30269895073301hr-1-p5.97.114551622

30270095077303hr-3-p6.07.06791673

30270195079304hr-4-p6.07.08681494

30270295081305hr-5-p5.36.912721135

30270395083306hr-6-p5.97.012531716

30270495085307hr-7-p5.86.913681847

30270595087308hr-8-p6.07.110901518

30270695089309hr-9-p5.56.910561299

30270795091310hr-10-p5.37.0284410710

30270895093311hr-11-p6.07.11010214311

30271095095312hr-12-p5.37.0176513012

30271195097313hr-13-p5.47.0126011613

30271295099314hr-14-p5.37.0134111014

302713950101315hr-15-p5.37.174911115

302714950103316hr-16-p6.07.21015016416

302715950105317hr-17-p5.77.295711917

302716950107318hr-18-p5.77.176911118

302717950109319hr-19-p5.16.95468719

302718950111320hr-20-p4.97.09408520

302720950113321hr-21-p5.67.2135510021

302721950115322hr-22-p5.47.1255712022

302722950117323hr-23-p5.07.028419823

302723950119324hr-24-p4.87.09257324

302758950121325hr-25-p5.07.07377025

Ave5.57.012.161.0124.0ave

Stdev0.40.16.325.231.1

CV7.11.351.741.425.1

30272495074401hr-1-a5.97.11682157

30272595076402hr-2-a5.87.11880139Lab 1Random 15.87.214109157

30272695078403hr-3-a6.06.9875145Lab 1Random 25.87.215105158

30272795080404hr-4-a5.87.01279145Lab 2Random 15.77.11898150

30272895082405hr-5-a5.47.01778104Lab 2Random 25.77.018100151

30273095084406hr-6-a6.07.21489160CIDD19-85.07.074390

30273195086407hr-7-a5.87.01468144CIDD18-85.17.01862114

30273295088408hr-8-a5.77.11381148

30273395090409hr-9-a5.67.01145119

30273495092410hr-10-a5.57.11354104

30273595094411hr-11-a6.07.2876123

30273695096412hr-12-a5.67.01473113

30273795098413hr-13-a5.57.1956103

302738950100414hr-14-a5.36.91347101

302740950102415hr-15-a5.36.9650105

302741950104416hr-16-a5.97.014100142

302742950106417hr-17-a5.77.11867114

302743950108418hr-18-a5.46.9154997

302744950110419hr-19-a5.06.793783

302745950112420hr-20-a4.96.994888

302746950114421hr-21-a5.87.21698139

302747950116422hr-22-a5.57.02048128

302748950118423hr-23-a5.26.81438114

302750950120424hr-24-a5.07.0112975

302751950122425hr-25-a4.97.084587

Ave5.518.517.162.6111.5

Stdev0.050.819.724.732.8

CV0.0274.2115.739.429.4

302752950123501Lab 1Random 15.87.214109157

302753950124502Lab 1Random 25.87.215105158

302754950125503Lab 2Random 15.77.11898150

302755950126504Lab 2Random 25.77.018100151

302756950128506CIDD19-85.07.074390

302757950127505CIDD18-85.17.01862114

Sheet1

Random Area

Center Area

Center Point

Cell Number

Soil Test P (pp2m)

Comparison of methods for sampling soil from 24 1-acre cells of a cultivated field, on soil STP.

Sheet2

82

80

75

79

78

89

68

81

45

54

76

73

56

47

50

100

67

49

37

48

98

48

38

29

45

62.5954751161

Random Area

Center Point

Cell Number

Soil Test P (pp2m)

Comparison of methods for sampling soil from 25 cells within 1.0 acre (cell 8) of a cultivated field, on soil STP.

Sheet3

Random Area

Center Area

Center Point

Cell Number

Soil Test K (pp2m)

Comparison of methods for sampling soil from 24 1-acre cells of a cultivated field, on soil STK.

Random Area

Center Area

Center Point

Cell Number

Soil pH

Comparison of methods for sampling soil from 24 1-acre cells of a cultivated field, on soil pH.

Random Area

Center Area

Center Point

Cell Number

Soil NO3-N (lb/acre)

Comparison of methods for sampling soil from 24 1-acre cells of a cultivated field, on soil NO3-N.

Random Area

Center Point

Cell Number

Soil Test pH

Comparison of methods for sampling soil from 25 cells within 1.0 acre (cell 8) of a cultivated field, on soil pH.

16

18

8

12

17

14

14

13

11

13

8

14

9

13

6

14

18

15

9

9

16

20

14

11

8

17.0534270969

Random Area

Center Point

Cell Number

Soil Test NO3-N (lb/acre)

Comparison of methods for sampling soil from 25 cells within 1.0 acre (cell 8) of a cultivated field, on soil NO3-N .

157

139

145

145

104

160

144

148

119

104

123

113

103

101

105

142

114

97

83

88

139

128

114

75

87

111.4517264684

Random Area

Center Point

Cell Number

Soil Test K (pp2m)

Comparison of methods for sampling soil from 25 cells within 1.0 acre (cell 8) of a cultivated field, on soil STK.

Comparison of Whole Field Sample between 2000, 2001 and 2002

Gvjsoils (1)

Point SamplesArea Samples

Cell NopHBISur NO3PKpHBISur NO3PK

17.3301442106.734161190

25.67.1321871855.87.245191192

36.5572642546.557248197

467.2292471856.27.323213185

567.31062162566.27.372177235

65.87.24714119867.249159189

75.47.1411341595.57.150133153

85.47.1241001385.57.119106151

95.57.112261365.37.12458121

105.37.120941405.77.22674134

114.96.967691545.273363162

125.1719391495.174168161

1356.9331241575.2733127180

1467.2201752035.87.118142192

1567.2431572466.17.327197245

166.27.35724328167.256227291

1767.2612222335.87.242164226

185.97.226951985.87.142143222

195.37.1371071595.37.138106168

205.5722601905.473568199

215.3742581885.373449191

225.4756681815.573252208

235.16.917441575.16.82758165

2456.931461504.96.94863157

1005.97.2601902065.77.137.7127.0188.1Ave

2005.97.2631881960.50.113.261.737.7stdev

3005.67.13311418682354920C.V.

4005.67.133117180

2016.734161190

2025.87.245191192

2036.557248197

2046.27.323213185

2056.27.372177235

20667.249159189

2075.57.150133153

2085.57.119106151

2095.37.12458121

2105.77.22674134

2115.273363162

2125.174168161

2135.2733127180

2145.87.118142192

2156.17.327197245

21667.256227291

2175.87.242164226

2185.87.142143222

2195.37.138106168

2205.473568199

2215.373449191

2225.573252208

2235.16.82758165

2244.96.94863157

1-acre cell number 8; high density sampling

Cell NopHBISur NO3PK

15.77.126108200

25.87.116113198

35.673499213

45.3740107152

55.57.138135150

65754121124

75.173879131

85.771690192

95.772186229

105.87.232104219

115.97.11487181

125.373897179

135.57.12682150

145.371866124

155.47.12482121

165.97.218119161

175.37.12882147

185.372063129

194.974164109

205.17.12479101

215.87.231120154

225.373080146

23572466127

244.773765106

254.77.1458097

average5.47.129.391.0153.6

TestspHNO3-NSTPSTK

Year000102000102000102000102

1A65.95.8196014139190109197206157

1B6.15.95.8186315141188105195196158

2A6.45.65.728331815711498185186150

2B6.45.65.7283318160117100199180151

Ave.6.25.85.8234716149152103194192154

Gvjsoils (1)

7.36.7

5.65.8

6.56.5

66.2

66.2

5.86

5.45.5

5.45.5

5.55.3

5.35.7

4.95.2

5.15.1

55.2

65.8

66.1

6.26

65.8

5.95.8

5.35.3

5.55.4

5.35.3

5.45.5

5.15.1

54.9

Point pH

Area pH

3430

4532

5757

2329

72106

4947

5041

1924

2412

2620

3367

4119

3333

1820

2743

5657

4261

4226

3837

3522

3442

3256

2717

4831

Area NO3-N

Point NO3-N

161144

191187

248264

213247

177216

159141

133134

106100

5826

7494

6369

6839

127124

142175

197157

227243

164222

14395

106107

6860

4958

5268

5844

6346

Area STP

Point STP

Cell

Soil Test-P

Soil test P variability among 25 1-acre cells in a field, 2001

194177

204236

266251

292263

192273

177161

70138

36150

12490

7145

73108

7649

149137

146178

206191

265211

214239

135139

119109

7972

6061

5778

6354

6553

138.875144.2916666667

Area

Point

Cell

Soil Test P

Soil test P variability among 25 1-acre cells in a field, 2000.

190210

192185

197254

185185

235256

189198

153159

151138

121136

134140

162154

161149

180157

192203

245246

291281

226233

222198

168159

199190

191188

208181

165157

157150

Area STK

Point STK

201226

210220

217209

223212

244266

153180

128155

106156

179135

159162

168129

161156

176159

200225

264292

292290

233245

216210

157161

201220

219202

220267

160154

137146

192.6666666667199.0416666667

Area K

Point K

Cell

Soil Test K

Soil test P variability among 25 1-acre cells in a field, 2000.

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

pH

NO3-N

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Soil pH

Residual NO3-N (lb/acre)

Comparison of Area of Sampling for 2002

Gvjsoils (1)

Area Samples

Cell NoBIPpHSur NO3PK

11446.734161190

27.11875.845191192

32646.557248197

47.22476.223213185

57.32166.272177235

67.2141649159189

77.11345.550133153

87.11005.519106151

97.1265.32458121

107.1945.72674134

116.9695.23363162

127395.14168161

136.91245.233127180

147.21755.818142192

157.21576.127197245

167.3243656227291

177.22225.842164226

187.2955.842143222

197.11075.338106168

207605.43568199

217585.33449191

227685.53252208

236.9445.12758165

246.9464.94863157

1007.21905.737.7127.0188.1Ave

2007.21880.513.261.737.7stdev

3007.11148354920C.V.

4007.1117

201161

2027.2191

203248

2047.3213

2057.3177

2067.2159

2077.1133

2087.1106

2097.158

2107.274

211763

212768

2137127

2147.1142

2157.3197

2167.2227

2177.2164

2187.1143

2197.1106

220768

221749

222752

2236.858

2246.963

1-acre cell number 8; high density sampling

Cell NoBIP

17.1108

27.1113

3799

47107

57.1135

67121

7779

8790

9786

107.2104

117.187

12797

137.182

14766

157.182

167.2119

177.182

18763

19764

207.179

217.2120

22780

23766

24765

257.180

average7.191.0

TestspHNO3-NSTPSTK

Whole Field5.816109157

1 acre grid5.4144598

Sub-grid5.3650105

Center area5.6142997

Center Point5.3749111

Gvjsoils (1)

7.36.7

5.65.8

6.56.5

66.2

66.2

5.86

5.45.5

5.45.5

5.55.3

5.35.7

4.95.2

5.15.1

55.2

65.8

66.1

6.26

65.8

5.95.8

5.35.3

5.55.4

5.35.3

5.45.5

5.15.1

54.9

Point pH

Area pH

3430

4532

5757

2329

72106

4947

5041

1924

2412

2620

3367

4119

3333

1820

2743

5657

4261

4226

3837

3522

3442

3256

2717

4831

Area NO3-N

Point NO3-N

161144

191187

248264

213247

177216

159141

133134

106100

5826

7494

6369

6839

127124

142175

197157

227243

164222

14395

106107

6860

4958

5268

5844

6346

Area STP

Point STP

Cell

Soil Test-P

Soil test P variability among 25 1-acre cells in a field, 2001

194177

204236

266251

292263

192273

177161

70138

36150

12490

7145

73108

7649

149137

146178

206191

265211

214239

135139

119109

7972

6061

5778

6354

6553

138.875144.2916666667

Area

Point

Cell

Soil Test P

Soil test P variability among 25 1-acre cells in a field, 2000.

190210

192185

197254

185185

235256

189198

153159

151138

121136

134140

162154

161149

180157

192203

245246

291281

226233

222198

168159

199190

191188

208181

165157

157150

Area STK

Point STK

201226

210220

217209

223212

244266

153180

128155

106156

179135

159162

168129

161156

176159

200225

264292

292290

233245

216210

157161

201220

219202

220267

160154

137146

192.6666666667199.0416666667

Area K

Point K

Cell

Soil Test K

Soil test P variability among 25 1-acre cells in a field, 2000.

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

pH

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

NO3-N

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Soil pH

Residual NO3-N (lb/acre)

Why Account for Spatial Variability of Soil PropertiesImprove performance of ag. practicesEither costs go down and/or returns go upAvoid over application that might be environmentally harmful

Analysis Costs of Various Sampling Intensities*at $10/sample

Grid SpacingArea/sampleCosts*FeetAcres$/acre660.11001040.25401480.5202091103302.5446752660101Conventional400.25

Choosing a Soil Sampling StrategyLevel of management and the resources to account for variabilityWhole field sampling most appropriate when fertility is high and variability is lowZoning/sub-field sampling may be most appropriate whenLocation of variation knownSampling areas are largeLimited resourceGrid sampling maybe appropriate if location of variation is unknown and variable rate applicator is available

How to use soil test information?

pH value defines relative acidity or basicity9.08.07.06.05.04.0Very strongStrongMediumModerateSlightSlightMediumStrongBasicAcidPure waterMost productive soilsVinegarLemon juiceAmmoniacleanerMake lime recommendation

NCaPMgKS16EssentialElementsCHOBClCuFeMnMoZnPlant Nutrient Recommendation

Sharpley et al., 1998

Remediate Contaminated Soil NormalEC (mmhos/cm)048121615ESP%SalineSodicIncreased salt hazard30Saline-Sodic

Soil, Water and Forage Analytical Laboratoryhttp://www.soiltesting.okstate.edu

*Precision nutrient management has been around for some times, because varying the rates of crop inputs to meet site-specific needs makes economic and environmental sense. I am going to spend a few minutes to talk about grid sampling based nutrient management strategy.*As far as I know, these are the main strategies researched and applied. The first 2 are soil based and the other 2 are crop based.*Those are the main purposes of soil tset*Main services provided*We have direct service to all county extension offices in the state***Here is a winter wheat field at the Research Station in Perkins. Again tremendous differences in wheat growth. The forage yields ranged from practically zero to over 2,500 lbs/A. What we found the problem was low soil pH and high Al level. The forage yields were highly correlated to the Al saturation percentage. *The farmer, or the person taking the soil sample, must provide the laboratory with a uniform, representative sample ... a critical component for the laboratory in providing accurate soil test results and fertilizer recommendations. Each sample, weighing only a pound or less, can represent millions of pounds of soil in the field. The greatest potential for error in soil testing is in taking the sample.

**This graph shows the variability of nitrate-nitrogen in a 75x75 area of a field. Each small plot is a 5x5 square. Nitrate-N ranged from 25 lbs/acre to 102 lbs/acre over the area. Each sample submitted for analysis should be representative of the the entire sampling area.Avoid taking sample from any unusual spots, such as, manure piles, cracks, etc, to avoid any misrepresentation.

Data gathered from OSU Agronomy Research Farm

*By taking enough soil cores randomly in a field to make a composite sample, one can hit the average nutrient status repeatedly.**Soil test P changes with depth. N,K, pH, and many other soil properties also change, especially when the field is not cultivated. Soil phosphorus on fields receiving top dressed poultry litter tends to accumulate near the soil surface.A 0-6 inch sample is recommended for consistent and reliable soil test results.

*The key components of a good sampling technique.*As far as I know, these are the main strategies researched and applied. The first 2 are soil based and the other 2 are crop based.*As far as I know, these are the main strategies researched and applied. The first 2 are soil based and the other 2 are crop based.*Have been realized the existence of field spatial variability, people have tried to account for them through management. This excise is to validate the existence of field variability using 3 different sampling schemes.*A grid soil sampling exercise was conducted in this 27 acre field for the last two years. The dept. of animal science manages this field and they will use it to receive manure from the new swine facility they are building.*Soil pH raged from 4.5 to 7.5. You will know where lime should be applied.*Have been realized the existence of field spatial variability, people have tried to account for them through management. Because:*As far as I know, these are the main strategies researched and applied. The first 2 are soil based and the other 2 are crop based.*It covers a scale ranging from zero to 14.0, with 7.0 being neutral neither acidic or basic. Most productive soils have pH values in the 5.0 to 8.0 range; however, acid or basic soils can be made more productive when properly managed. The relative degrees of acidity and basicity are shown here.

*Sixteen chemical elements have been shown to be essential for plant growth. That means the plant cannot complete its normal life cycle if just one of these nutrients is limiting. They are divided into two main groups, non-mineral and mineral.*As soil P increases, so does crop yield and the potential for p loss in surface runoff