Precision Nutrient Management

Brian ArnallDepartment of Plant and Soil Sciences

Oklahoma State University

Precision Ag Class 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.

Variable Rate Tech Does VRT fertilizer (not lime) Result in More uniform yield across field More variable yield across field

Precision Nutrient Management Land

› Soil type, Slope, H20 Movement Soil

› Soil sample Composite, Zone, Grid

› Soil EC› Soil color

Plant› Tissue› Sensor› Yield

To Each His Own What is the problem What is the goal Time and Money Investment

Independence of Variables 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

Determining the Variable

P KP

Elevation

Buffer IndexBuffer Index

Lime required (tons 100% ECCE)

pH 6.8 pH 6.4

Over 7.1 None None7.1 0.5 None7.0 0.7 None6.9 1.0 None6.8 1.2 0.76.7 1.4 1.26.6 1.9 1.76.5 2.5 2.26.4 3.1 2.76.3 3.7 3.2

PhosphorusSoil Test P

Index

% Sufficien

cy

P2O5 lbs/a

c0 25 8010 45 6020 80 4030 85 3040 90 20

65+ 100 0

Soils Sampling

Soil Sampling

Sensors

Yield Monitor

Apps 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

First VRT VRT Lime due to cost/acre and

variability

Summary Now the reasons and goals Understand limitations Don’t have

to dive in Head first

Thank you!!!

Brian Arnall373 Ag Hall405-744-1722b.arnall@okstate.eduPresentation available @ www.npk.okstate.eduTwitter: @OSU_NPKYouTube Channel: OSUNPK

www.extensionnews.okstate.edu