1. Oklahoma State University
SOIL 4213 BIOEN 4213
Grid Sampling, and the Future of Soil Sampling
Oklahoma State University

2. 1 Acre Grid, 16 Acres
490ft2
43560ft2
= 0.01
x x x x

3. Forage yield NDVI MehlichIII P70 60 50 40 30 20 10 70 60 50 40 30 20 10 70 60 50 40 30 20 10
lb/ac
8400
7200
6000
4800
3600
2400
1200
ppm 56 49 42 35 28 21 14 7
0.84
0.78
0.72
0.66
0.60
0.54
0.48
0.42
0.36
0.30
Distance, ft
Distance, ft
Distance, ft
Distance, ft
Distance, ft
Distance, ft

4. SOIL SAMPLING…. RESOLUTION?
Grid: 1 acre, 43560ft2 (1) 1
Yield Monitor: 900 ft2 (0.02) x48
Resolution Study: 490ft2 (0.01) x89
OSU-VRT: 10ft2 (0.0002) x4356

5. x 4840 160 acre field ($10/soil sample) Sensor Based Map Based 1 Acre
43560 ft2
900 ft2
9 ft2
48.4
100
x 4840
Grid Based
$1600
Map Based
$77,440
Sensor Based
$7,744,000
160 acre field ($10/soil sample)
1 Acre

6. Mean surface soil test P and fertilizer P recommendations,
bemudagrass pasture, Burneyville, OK 70 30
Mehlich III 60
P Fertilizer 25 50 20
P FERTILIZER, kg/ha
MEHLICH III P, mg/kg 40 15 30 10 20 5 10 2 4 6 8 10 12 14 16 18 20 22
DISTANCE, m

7. Mean surface soil test NH4-N + NO3-N and fertilizer N
recommendations, bemudagrass pasture, Burneyville, OK 30
140 25
120 20
100
NH4-N + NO3-N, mg/kg
N FERTILIZER, kg/ha 80 15 60 10 40 5
NH4-N + NO3-N 20
N Fertilizer 2 4 6 8 10 12 14 16 18 20 22
DISTANCE, m

8. ‘Precision agriculture’ and ‘variable rate’ technologies must operate at the resolution where real differences are encountered in the field.
OSU Team VRT

9. http://www.cropquest.com TEMPORAL VARIABILITY (South Carolina)
Management Zones (PIONEER), Tom Doerge
GRID SOIL SAMPLING (SOIL DOCTOR) last graph = every 6 square feet
Soil Sampling as a Basis for Fertilizer Application, NDSU, Dave Franzen
Systematic Evaluation of Precision Farming Soil Sampling Requirements, USDA-ARS, South Dakota
Soil Sampling Strategies for Site Specific Management, Manitoba, CANADA (go to definition of Grid Soil Sampling)
University of Georgia (NESPAL)

10. x x x x

11. Class Presentations (turn in title by February 23)
Netscape Navigator (hyperlinks are dead)
Make – up lecture…….
005 Computer Lab, Will Answer questions 2:30-3:20
Spatial Variability

12. National Geographic 1996
Southern Russia

13. Oklahoma

14. Oklahoma

15. Oklahoma

19. England

20. Bermudagrass, Burneyville, OK Prefertilization May 28
FR1
FR1 C1
VR1
VR2 C2
FR2
FR2 5 10 15 20 25 30 35 40 45
Bermudagrass,
Burneyville, OK
Prefertilization
May 28
Distance, m 5 10 15 20 25 30 35 40
Distance, m

21. following fertilization
FR1
FR1 C1
VR1
VR2 C2
FR2
FR2 5 10 15 20 25 30 35 40 45
Bermudagrass,
Burneyville, OK
First harvest
following fertilization
June 27
Distance, m 5 10 15 20 25 30 35 40
Distance, m

22. 120’ 130’ 1.33 PNSI 1.12 0N,0P 100N, 120P Hasil Sembiring
OSU Soil Fertility

23. N Fertilization Rate, lb/ac
Distance, ft 4 14 24 34 44 54 64
Variable N Rate: 36.3 lb N/ac
Fixed N Rate: 80.0 lb N/ac
43.7 lb N/ac

24. Resolution of Soil Fertility Variables
Organic Matter Range: