
Wheat Lots of $
› Sprayer, No-till/Air seeder, GPS, Yield Monitor,
Combine,

Wheat a little $
› Grid, Veris, GPS Yield Monitor, Nrich and GS

Corn Lots of $
› Planter, Strip till, Zones

Corn a little $
› Planter upgrade, Gird, GS, Zone.
Does VRT fertilizer (not lime) Result in
 More uniform yield across field
 More variable yield across field


Land
› Soil type, Slope, H20 Movement

Soil
› Soil sample
 Composite, Zone, Grid
› Soil EC
› Soil color

Plant
› Tissue
› Sensor
› Yield
What is the problem
 What is the goal
 Time and Money Investment

If you want to fix everything
 Don’t chase after one thing.
 Yield Monitor data for

› Phosphorus Potassium Lime

Soils data for
› Nitrogen and Sulfur
N and S (mobile) are yield based
 P and K (immobile) are soil test based
 Lime is Buffer Index based


Using 1 factor to determine other
unrelated factors
P
P
Elevation
K
Lime required
(tons 100% ECCE)
Buffer
Index
pH 6.8
pH 6.4
Over 7.1
None
None
7.1
0.5
None
7.0
0.7
None
6.9
1.0
None
6.8
1.2
0.7
6.7
1.4
1.2
6.6
1.9
1.7
6.5
2.5
2.2
6.4
3.1
2.7
6.3
3.7
3.2
Soil Test P
Index
%
Sufficienc
y
P2O5
lbs/a
c
0
25
80
10
45
60
20
80
40
30
85
30
40
90
20
65+
100
0

I have 29 Ag apps on my I-Pad
› 27 were free
I use 6 regularly
 Identification

› weed and nutrient

Easy to use Calculators
› Spray and fertilizer

John Deere, Pioneer, Monsanto, Hew
Holland, ect ect ect ect. Customer based

VRT Lime due to cost/acre and variability
Now the reasons and goals
 Understand limitations
 Don’t have
to dive in
Head first

www.extensionnews.okstate.edu
Brian Arnall
373 Ag Hall
405-744-1722
b.arnall@okstate.edu
Presentation available @
www.npk.okstate.edu
Twitter: @OSU_NPK
YouTube Channel: OSUNPK