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TRANSCRIPT
Why?
How?
What?
• WHY – Field variability exists
• HOW
– Assess spatial variability
• WHAT – Variable rate applications
Field Variability
Why?
How?
What?
Field Variability
Why?
How?
What?
Field Variability
Why?
How?
What?
Field Variability
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
Field Variability
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
Field Variability
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
Economic Benefit
Why?
How?
What?
Environmental Benefit
Why?
How?
What?
Environmental Benefit
Why?
How?
What?
Assessing Field Variability
• Soil Sampling
• Normalized Yield Data
• Soil Electrical Conductivity (EC)
• Topography
• Soil Maps
Why?
How?
What?
Soil Sampling
Why?
How?
What?
Grid
G
Grid-Point Sampling Grid-Cell Sampling
Grid-Point – fields with little variability
Grid-Cell – fields with variability
10 – 15 soil cores
Soil Sampling
Why?
How?
What?
2.5
2.5 5
10
Soil Sampling
Why?
How?
What?
Soil Sampling
Why?
How?
What?
Grid Resolution
Soil Sampling
Why?
How?
What?
Grid Resolution – P2O5
2.5 acre grid 5 acre grid
150 bu corn
Soil Sampling
Why?
How?
What?
Grid Resolution – P2O5
2.5 acre grid 5 acre grid
P2O5 (lbs/A)
Area (A)
DAP (lbs)
Area (A)
DAP (lbs)
Low 120 4.7 1226 8.1 2113
Medium 60 12.7 1657 13.9 1813
High 0 21.6 0 17 0
Total 2883 3926
Soil Sampling
Why?
How?
What?
Grid Resolution – P2O5
2.5 acre grid 5 acre grid
P2O5 (lbs/A)
Area (A)
DAP (lbs)
Area (A)
DAP (lbs)
Low 120 4.7 1226 8.1 2113
Medium 60 12.7 1657 13.9 1813
High 0 21.6 0 17 0
Total 2883 3926
Using 2.5 acre grid vs. 5 acre grid saved this producer
$8.56/ac and 480 lbs P2O5
Soil Sampling
Why?
How?
What?
Grid Resolution – K2O
2.5 acre grid 5 acre grid
150 bu corn
Soil Sampling
Why?
How?
What?
Grid Resolution – K2O
2.5 acre grid 5 acre grid
K2O (lbs/A)
Area (A)
Potash (lbs)
Area (A)
Potash (lbs)
Low 120 11.1 2220 14.2 2840
Medium 60 23.1 2310 20.2 2020
High 0 4.6 0 4.5 0
Total 4530 4860
Soil Sampling
Why?
How?
What?
Grid Resolution – K2O
2.5 acre grid 5 acre grid
P2O5 (lbs/A)
Area (A)
DAP (lbs)
Area (A)
DAP (lbs)
Low 120 11.1 2220 14.2 2840
Medium 60 23.1 2310 20.2 2020
High 0 4.6 0 4.5 0
Total 4530 4860
Using 2.5 acre grid vs. 5 acre grid saved this producer
$2.52/ac
• Normalized Yield Data
• Soil Electrical
Conductivity (EC)
• Topography
• Soil Maps
Defined Management Zones
Zone Management
Why?
How?
What?
Yield Maps
Why?
How?
What?
You Need Multiple Years of Yield Data
𝒙𝒙 = 𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚 𝒑𝒑𝒑𝒑𝒚𝒚𝒑𝒑𝒑𝒑 𝒙𝒙� = 𝒂𝒂𝒂𝒂𝒚𝒚𝒂𝒂𝒂𝒂𝒂𝒂𝒚𝒚 𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚𝒚
𝑵𝑵 = 𝒙𝒙𝒙𝒙�∗ 𝟏𝟏𝟏𝟏𝟏𝟏
Yield Maps
Why?
How?
What?
Field Average 174 bu/ac
Yield Maps
Why?
How?
What?
𝟏𝟏𝟏𝟏𝟏𝟏 𝒃𝒃𝒃𝒃/𝒂𝒂𝒂𝒂𝟏𝟏𝟏𝟏𝟏𝟏 𝒃𝒃𝒃𝒃/𝒂𝒂𝒂𝒂
= 𝟏𝟏.𝟏𝟏𝟏𝟏
𝟏𝟏𝟏𝟏𝟏𝟏 𝒃𝒃𝒃𝒃/𝒂𝒂𝒂𝒂𝟏𝟏𝟏𝟏𝟏𝟏 𝒃𝒃𝒃𝒃/𝒂𝒂𝒂𝒂
= 𝟏𝟏.𝟖𝟖𝟏𝟏
Yield Maps
Why?
How?
What?
Average yield by zone
% of Field Corn Beans Cotton Low 18 91 45 617
Medium 59 132 63 910 High 23 144 70 1025
Soil EC
Why?
How?
What?
6 – 23 mSiem/m
5 – 224 mSiem/m
Soil EC
Why?
How?
What?
Topography
Why?
How?
What?
Topography
Why?
How?
What?
Soil Type
Why?
How?
What?
Why?
How?
What?
Data-Driven Decisions
Variable Rate Applications • Fertilizer • Seeding • Irrigation • Other
– Chemical application – Manure spreading
Why?
How?
What?
If we used blanket rates of…
2500 lb/A (+$6/A)
200 lb/A (+$5/A)
30 lb/A (+$2/A)
VR Fertilizer
If we used blanket rates of…
2000 lb/A (+$8/A)
200 lb/A (-$2/A)
150 lb/A (+$6/A)
VR Fertilizer
If we used blanket rates of…
2750 lb/A (+$4/A)
200 lb/A (+$9/A)
30 lb/A (+$4/A)
VR Fertilizer
VR Seeding
Why?
How?
What?
VR Seeding
Why?
How?
What?
VR Seeding
Why?
How?
What?
2013
2014
*No statistical differences were observed between seeding
rates
Average Soybean Yield
by Seeding Rate
Why?
How?
What?
VR Seeding
Why?
How?
What?
VR Seeding Inside versus Outside of Center Pivot
• Basically it is being precise with our irrigation applications by knowing: – When to Irrigate – How often to Irrigate (frequency) – How much to irrigate – Where (spatially) to irrigate
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
• Cannot realize benefits from variable rate fertilization, lime, seed, etc. if we do not first properly manage water.
• Water conservation and water use efficiency are critical issues.
• Already regulatory actions restrict agricultural water use.
• It is EXPENSIVE to irrigate.
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
• Variable rate irrigation is the controlled rate and placement of water based on measured conditions.
• In many cases water is wasted throughout a field due to: – Overlap – Field variability – Wet or low area – Poorly drained soils/Well drained soils – Water being applied to a non-crop area
• Management control zones are developed based on field conditions, crop needs, and feasible control size.
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
• Implement widths • Soil EC • Soil Type • Elevation • Field Size • Irrigation Tower Length • Single or Multiple Crops
VR Irrigation – Zone Development
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
• How large do I want my management zones? – What is feasible for my operation? – What type of field resolution do I want? – How long is my irrigation tower? – How many nozzles do I have? – How wide do the management zones need to be? – The higher the resolution the more control equipment
required. – Two nozzles per zone would be the minimum. – Keep in mind that smaller zones can be treated uniform
and “merged”, but larger zones cannot be divided once the control system is implemented.
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
• How am I currently scheduling my irrigation? – Using VR will require a
more intensive management and scheduling strategy.
– Moisture sensors in every zone? In similar zones?
– Do I want to work towards an automated system or would I be better off calculating and entering each zones needed rate separately?
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
Soil Electrical Conductivity, at
planting
Aerial Photography,8
Weeks After Planting
Seed Cotton Yield
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
Yield Data • Soil fertility, type, etc. • Disease or insect pressure • Variety differences • Poorly drained areas • Compacted areas • Does not point out the yield limiting variable, it
only indicates the response to it.
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
• Identify and quantify yield variability within fields. • Use the identified zones to make management zones
and decisions. • Use the management zones to adjust crop inputs.
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Zone Development
• A VR system requires: – A control system for each developed zone
• Can consist of electronic or pneumatic valves – A control software for inputting the developed
zones and supplying a control signal – Differential GPS (for accurate location of the
system) – Either a variable frequency pump or pressure relief
to account for changes in flow and pressure due to varying zones.
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
VR Irrigation – Mechanics
• Total area = 228 ac
• Not cropped area = 84 ac (37%)
• 84 ac × 12 in irrigation = 1008 ac-in ► $12,096
► 27.3 million gallons / year
VR Irrigation
Why?
How?
What?
Information provided by: Dr. Wes Porter, UGA
Recap • Why?
– Spatial variability • How?
– Assessing variability • What?
– Variable rate applications
Why?
How?
What?
Take Home Message
Why?
How?
What?
• Variability exists in all fields – OPTIMIZE! • VR fertilizer application places the right
rate at the right place • Zone management requires precision ag
data • VR seeding has the potential to
maximize profitability • VR irrigation conserves water and lowers
irrigation costs
Lori Duncan Biosystems Engineering
UT Extension [email protected]
(865) 974-7111
Mike Buschermohle Biosystems Engineering
UT Extension [email protected]
(865) 974-7142