Sensor-based Nitrogen Management for Cotton in
Coastal Plain Soils
Sensor-based Nitrogen Management for Cotton in
Coastal Plain SoilsPhillip Williams, Ahmad Khalilian,
Michael Marshall, Jose Payero,
Ali Mirzakhani
71st SWCS International Annual ConferenceLouisville, KY, July 24-27, 2016
ACKNOWLEDGMENTSThis Demonstration project is supported by:
USDA/NRCS CIGAward No. 69-3A75-14-268
Clemson Public Service Activities
This Demonstration project is supported by:
USDA/NRCS CIGAward No. 69-3A75-14-268
Clemson Public Service Activities
ClayClay
SandSand
Sandy LoamSandy Loam
Field variations result in the developmentof plants with a tremendous amount ofgrowth variability, which have a majorimpact on fertilizer management strategies.
Cotton Yield
Cot
ton
Lint
(lbs
/acr
e)
Soil EC (mS/m)
R2
= 0.9202
0
300
600
900
1200
0 2 4 6 8
Soil EC, at planting
N Rate (lbs/A)
LowEC: Medium High
0
500
1000
1500
2000
2500
0 20 40 60 80 100 120 140
Effects of soil EC and N rate on seed cotton yields (lbs/acre)
Seed
Cot
ton
Yiel
d
Several researchers have developed algorithms for sensor-based N applications for corn, cotton & wheat.
However, due to higher precipitation, significant variation in soil texture, low soil organic matter content, and low nutrient holding capacity of soils in Coastal Plain regions, N-application algorithms, developed at other regions, either under- or over-estimated nitrogen rates for crop production.
EC Zones
Seed
Cot
ton
Yiel
d Effects of Nitrogen Management
Systems on Cotton Yield
Clemson
Farmer
OSU
Low Medium High0
500
1000
1500
2000
2500
3000
Clemson Yield Prediction Equations
INSEY
Seed
Cotton Yield
y = 320.31e112.2x
R² = 0.761
y = 502.82e116.07x
R² = 0.8837
0
500
1000
1500
2000
2500
3000
3500
0 0.005 0.01 0.015 0.02 0.025
Irrigated
Dry Land
Algorithm ComparisonClemson Algorithm OSU Algorithm
YP0= 235.96 e 2216.2 * INSEY
INSEY= NDVI/Cumulative GDD
RI = 1.8579 * RINDVI – 0.932
%N= 0.09
NUE = 0.50
(YP0 * RI –YP0) * %NN Rate =NUE
YP0= 413.46 e 104.98 * INSEY
INSEY= NDVI/# Days After emergence
RI = High NDVI/Field Avg. NDVI
%N= 0.04
NUE= 0.50
EC Zones
Seed
Cot
ton
Yiel
d (lb
s./a
cre)
Sensor:47 lb./A Conv.:90 lb./A ($48% less)
Low Medium High0
1000
2000
3000
On average, growers in the US apply about 90 lb./acre N for cotton, for a total of 1.7 million tons.
Sensor-based N application has the potential to reduce nitrogen rates by half. Even a 20% reduction in nitrogen rate could save our cotton growers over $100 million annually.
Objective To demonstrate the benefits of
sensor-based nitrogen management strategies to growers, utilizing plant NDVI, Clemson algorithms for Irrigated and dry land cotton, soil amendments, and soil electrical conductivity (EC) data (management zones).
Overall Objective To assist cotton, corn, and wheat
farmers in the Southeastern Coastal Plain region, to adopt innovative and proven conservation technologies for achieving 4R (right source, rate, time, and place) nutrient management.
Demonstration Sites (2015-16)
Al Cribb FarmWalker Nix FarmJeff Lucas FarmWilliams FarmJB FarmsBates FarmEdisto REC (3 sites)Pee Dee REC (2 sites)
Identifying management zones
Establishing nitrogen rich strips
Measuring NDVI utilizing sensors
Calculating nitrogen requirements
Methods for Managing Nitrogen
Soil ElectricalConductivity (EC) meter
EC Map, Cribb Farm
Identifying management zones
4 rows by 50 feet; More nitrogen than theplants can use is applied (150 lbs/A for cotton).
Establishing nitrogen rich strips
Measuring NDVI utilizing sensorsNDVI = (NIR - Red) / (NIR + Red)
Handheld Data Collection
• Handheld units– Mobile– Cost effective
• Only does small area but gives average
Whole Field NDVI Mapping• Sensors mounted on sprayer booms,
fertilizer applicators, or any mobile field equipment.
• Provides a whole field map that can be used in fertilizer applicators or can apply fertilizer “on-the-go”.
Aerial Mapping• Unmanned Aerial Vehicle (UAV) can be
used to fly over fields and collect data that can then be made into a prescription map.
Calculating nitrogen requirements• Excel file can be used to calculate N rates.• NDVI data from UAV, handheld, or field
equipment can be used as input.
Mobile Application and Website
The application is designed for smartphones, tabletsand computers.
Planting DateNDVI: N Rich StripNDVI: FieldMax Yield HistoryIrrigated or Dryland
N-rates for each zone
Variable-rate Nitrogen Applicator Rawson Hydraulic Controller
2015 Test Results
Farm Previous Crop
N At Planting (lbs./acre)
Sensor‐based N Zone 1 Zone 2
(lbs./acre)
Grower N rate
(lbs./acre)
N Saved (lbs. /acre)
Savings ($/acre)
Walker Peanuts 0 40 20 90 50 ‐70 30 ‐ 42
Al Cribb Cotton 45 0 0 90 45 27
Jeff Lucas Clover Chicken
litter 0 0 90‐100 90‐100 54‐60
Pee Dee Cotton 0 40‐100 Ave. 60 75 15 9
Statistically there were no differences in cotton yields between farmers’ practice and sensor-based method at all locations
There is a potential to use mid-season plant NDVI data for variable-rate application of N fertilizer in cotton production, in a user friendly manner that growers and extension can utilize.
Summary
Soil EC management zones should be used for calculating nitrogen application rates in the Southeastern Coastal Plain region. This in addition to sensor technology can work in conjunction to give growers more information to make better management decisions.
Summary
Soil amendments (such as poultry litter) and/or previous crops (such as a legume like peanuts or soybeans) had a significant effect on required nitrogen rates determined by a sensor.
Summary
Sensor-based N management techniques, reduced nitrogen usage by 15 to 100 lbs./acre in cotton, compared to growers‘ application rates. This resulted in $9 to $60 savings/acre.
Summary
Questions?Questions?