This document summarizes a precision agriculture project that validated prescription maps for variable rate seeding and fertilizer application. The project involved collecting yield data and soil samples from fields to create data layers and prescription maps delineating management zones. Strip trials within the zones then tested different seeding and fertilizer rates, finding that higher than needed rates did not increase yields or profits. The project aims to help farmers optimize input costs through site-specific management informed by agronomic validation and data analysis.

1. Precision Agriculture
Prescription Validation
Nicole Rabe (Land Resource Specialist)
Environmental Management Branch
OMAFRA
Feb 14, 2017.

2. Co-operator yield
data submitted
+
collect other base
data layers to fill gaps
Goals: wireless
data transfer &
analyze data layers
with transparent
mathematics for
teaching farmers
Rx maps:
implemented with
validation built in
& industry
support
Current Project:
This project was funded in part through Growing Forward 2, a federal-
provincial-territorial initiative.
The Agricultural Adaptation Council assists in the delivery of Growing
Forward 2 in Ontario.

3. Requirements
for Sites:
• ~50 acres
• Corn, soy, wheat
rotation
• good drainage
• average to medium
base levels P & K
• Manure history is
fine BUT during
project would have
to be monitored
for impacts
• Farmer had to have
VR equipment for
at least 1 project
operation (seed or
fertilizer )
Goal: site-specific management of
two most expensive inputs:
1. Seed
2. Fertilizer (nitrogen)
Total of 20-25 fields (constant), 3 year study (2015-2017)

4. Base Data Layers
4
Elevation: Topographic Wetness Potential7 Year - Yield Potential Index (YPI)
UAV Natural Colour
Image
July 2016
Electrical
Conductivity
Proxy for Soil
Texture
Highest producing areas
Middle
Lowest producing areas
Baseline Soil Chemistry
Directed 1 ac grid

5. AGRONOMIC VALIDATION?
Action of checking or proving the validity or accuracy of something. A
technique required in controlled trials….

6. 2016
Strip Trial
Examples
Variable Rate Nitrogen
VR Soybean Population

7. 2016 “Learning Stamp” Example
7
Prescription Maps
Yield Potential Index
based so far…
As-Applied
Verification of Equipment
Cleaned Yield Data

8. Case Study 1: VR Population
Soybeans
Perth County: Learning Stamps 8yrs yield
8
Year Crop Mean
2007 Soybeans 45.76
2008 Wheat 97.11
2009 Corn 181.17
2010 Edible
Beans
32.03
2011 Wheat 88.90
2012 Corn 191.21
2013 Edible
Beans
49.19
2014 Wheat 81.16
2015 Corn 196.51

9. Soybean Theory
- low zones get high seeding rates
- high zones get low seeding rate (due to
disease pressure)
• Each grid is planter width of 30ft
• Stamps 90x90 ft
• To see response we have extra
low (100k sds/ac) & extra high
(200k sds/ac)
Yield Potential Index

10. 1.99 2.63
4.07 4.67
13.36
0
5
10
15
May June July Aug Total
Precip Monthly
(CoCoRahs CAN-ON-185)
Validation through the
growing season…
Acknowledge UAV Partner:
Green NDVI
June 29th 2016
Soybean Population
Count
July 6, 2016
Each point represents a
transect for population counts

11. The value of sufficient replication
in each management zone
HIGH Zone
– No statistical diff. for yield or economics from 100 to 200k sds/acre
– Supports theory that lower seeding rates is good assumption,
– Rx rate of 100k sds/ac was good
MEDIUM Zone
– No statistical diff. for yield or economics from 100 to 200k sds/acre
– Medium rate was fine at 150k sds/ac
LOW Zone
– No statistical difference for yield; tendency for lower yields with
increasing seeding rates.
– Economics: $97/ac loss from 100 to 200 thousand seeds/ac
– Rx theory that higher rate in low yielding zone was incorrect
Overall YPI Zone Assessment:
Soybeans in the higher yield mng’t zone actually did yield
higher than the low (+6.6bu/ac) and medium (+4.7bu/ac)
yield mng’t zones
[F-test significant at p= 0.04]
Zone
& Rate
Avg yield
(bu/ac)
Economics*
($/ac)
HIGH
100 64.1 $ 809.67
125 63.3 $ 782.71
200 66.1 $ 779.19
LOW
100 60.2 $ 755.83
175 58.6 $ 690.68
200 57.0 $ 655.55
MED
100 58.4 $ 730.96
150 62.8 $ 762.02
200 62.6 $ 730.94
*Soybean Price: $13.50/bu / Seed Cost $0.57 per 1000 seeds. Return calculated as
(13.5*Yield)-(0.57*Target Seeding Rate in thousands)

12. Case Study 2: VR Population Soybeans
Municipality: City of Ottawa
• Formerly 1-1 was pasture, lighter soils
• 305-2 & 305-3 cropped longest, tiled drained
7yrs ago, some compaction
• 305-7 Long term hay until 5yrs ago
Statistic
(Yield
bu/ac)
2011
Corn
2013
Corn
2014
Soybeans
(Partial)
2015
Corn
(VR-N)
Min 102.11 60 25.07 90.21
Max 238.22 287 61.91 299.73
Mean 177.33 208 46.34 221.48
X-Factor 2.33 4.29 2.47 3.32

13. Peaks / Tops of knolls
Upper Slopes
Lower Slopes
Lowest areas /
Depressions
RTK-GPS
Elevation
Survey
2015

14. Electrical
Conductivity
1m shallow
Dual EM
CEC Soil Test
2014 – 1ac grid
directed

15. 2 rep’s in the low yield zone
3 rep’s in the medium
2 rep’s in the high zone
**lack of 3 rep’s in each zone
lowers confidence in statistics
Remember theory:
High corn yielding zones
get low soybean seeding
rates & vice versa
3 yr Corn YPI
2016 Prescription Map

16. 2.4
0.9
3 2.6
4.1
13
0
2
4
6
8
10
12
14
April May June July August Total
VVF - Rainfall (Inches)
2016
Soybean
Yield Map

17. Zone Target Yield Return*
High 120 67.7 $ 839.86
High 155 65.6 $ 793.58
High 175 67.3 $ 801.53
Low 120 67.2 $ 838.41
Low 155 68.0 $ 824.34
Low 175 66.8 $ 802.40
Med 120 66.7 $ 815.49
Med 155 67.4 $ 829.73
Med 175 67.6 $ 808.14
*Soybean Price: $13.50/bu .Seed Cost $0.57 per 1000 seeds.
Return calculated as (13.5*Yield)-(0.57*Target Seeding Rate in thousands)
Overall YPI Zone Assessment: Soybean yield and
yield response to seeding rate were similar for all
zones of this field in 2016.
Seeding Rates:
• Seeding rates of 120, 155 and 175 thousand seeds/ac produced similar soybean
yields within each of the 3 management zones.
• no economic advantage associated with planting soybeans at a seeding rate that
exceeded 120,000 seeds/acre in 2016 in each of the 3 management zones.
2016 Results

18. Acknowledgements
Ian McDonald (Crop Innovation Specialist)
Ben Rosser (Corn Specialist)
Ken Janovicek (UofG – Research Assistant)
Thank-you!
nicole.rabe@ontario.ca