5. Ammonia Cost and Natural Gas Price
Source: NYMEX Henry Hub, Fertecon, PotashCorp (August, 2014)
6. Nitrogen Use Efficiency (NUE)
World Nitrogen Use
Efficiency (NUE):
~33%
(Raun and Johnson,
1999)
7. Dead Zone, Northern Gulf of Mexico
For 2014 August 1, the
area of Hypoxic zone is
13,080 sq.km (5,052 sq.
miles) is below 5 year
average.
Source: Nancy N. Rabalais
http://water.epa.gov/type/watersheds/named/msbasin/images/hypoxia_size_2013_
lg.jpg
8. Dead Zone, Northern Gulf of Mexico
Source: http://www.gulfhypoxia.net/overview/
Excess nitrogen flowing down
the Mississippi each year is
estimated to be worth
$750,000,000 (Science, Malakoff,
1998)
11. Nitrogen Application
Nitrogen: required in highest quantity.
Only preplant application have lowest NUE.
Top-dress or side-dress mid-season N applications can
increase NUE (>50%).
Fall N application has higher risk of N loss.
Spring application can minimize risk and optimize profitability
regardless of tillage (Vetsch and Randall, 2004).
12. Nitrogen related facts
Optimum N rate and NUE changes from year to year.
y = 0.0199x + 5.7962
R² = 0.29
y = -0.0114x + 6.116
R² = 0.11
0
5
10
15
20
25
0 50 100 150 200 250
YIELD,MGHA-1
OPTIMUM N RATE, KG HA-1
Central Great Plains, (1958-2010)
High N Check 0N
13. Free Environmental N: Total Atmospheric N
Source: National Atmospheric Deposition Program, 2014
14. Soil organic matter, N supply
The pattern of supply of N made available
through net mineralization of soil organic
matter N at three sites in Ireland.(Humphreys
et al., 2002)
15. Current Oklahoma State University Approach
Nitrogen Rich Strip
OSU GreenSeeker Sensors/Pocket Sensors
Variable Rate Applicator
Sensor Based Nitrogen Rate Calculator
Wheat and Corn Algorithm
Web-Based N recommendations
Grain Protein Optimizer
Ammonia Loss Calculator
GreenSeeder Hand Planter
16. Nitrogen Rich Strip
An area of field with high rate of nitrogen or non-N
limiting conditions.
40-50 pounds N/acre, over the average rate.
10 ft wide, 300 ft long.
Simple, affordable.
Starting from preplant application to 30 days planting
wheat.
17. Nitrogen rich Strip
Compare N Rich with farmer practice (visual difference)
Sensors to calculate needed N
Mid-season N application
Approach helps determine N coming from the
environment
Minimize environmental damage from excess N
21. OSU GreenSeeker Sensors/Handheld Sensors
(1992-2002)
Measure crop vigor through Normalized Difference
Vegetative Index (NDVI).
NDVI is calculated using the equation.
NDVI = NIR ref – red ref / NIR ref + red ref
NDVI values range from 0-0.9.
Values near 0.9 are likely non limiting N/healthy plant,
22. OSU GreenSeeker Sensors/Pocket Sensors
(1992-present)
OSU Commercial release GreenSeeker™ in 2002.
Optical Sensor/active sensor based technology
Emits near infrared and red light which is reflected by
the crop
Pocket sensors are more affordable, portable and lower
cost (500 $)
30. Sensor Based Nitrogen Calculator
(SBNRC)
GreenSeeker NDVI data (wheat, corn, other crops).
Yield potential for a crop is identified using NDVI and
planting date (can then compute GDD)
INSEY = NDVI (each date) / (GDD) days from planting
Where GDD= Growing Degree Days from planting
Guides producer to apply the optimum N rate
31.
32.
33. Sensor Based Nitrogen Rate Calculator
United States Outside the States
US Grain Belt-Winter Wheat
US-Spring Wheat-Rainfed
US Grain Belt-Corn(Rainfed and Irrigated)
S.Australia
E.Australia
Mexico-Spring Wheat-Rainfed
Brazil
Bermudagrass-Forage
Wheat-Forage-Pasture
Great Plains, Kansas-Sorghum
Minnesota, Ohio- Corn
North Central-Cotton
South West Irrigated-Cotton
Argentina
Canada- Spring Wheat, Canola
India-Rice, Spring Wheat
Kenya Rice-Dominion Farms
Colombia-Corn
Zimbabwe-Corn
34. Nitrogen Fertilization Algorithm
YP0: Estimate grain yield potential using NDVI and
cumulative GDD
RI :N Responsiveness estimated using NDVI in the N
Rich Strip and NDVI in the farmer practice or check
CV: Coefficient of variation determined from NDVI
sensor readings collected in each plot
35. Response Index
Yield response to additional N changes
N responsiveness = Response Index (RI)
RI = Grain yield (Highest N rate or N rich Strip)/Grain yield
(Check 0-N)
In season RI : Highest NDVI / NDVI from check
N response (RI) changes each year
38. Yield potential and nitrogen response
are independent
(Arnall et al., 2013, Agron J. 105:1335-1344)
39. Optical sensor based Winter Wheat
Algorithm
INSEY = NDVI/(days where GDD>0)
YP0 = 590exp(INSEY*258.2)
RI = 1.69(NDVI168kgN/NDVI28kgN) - 0.7
YPN = YP0 * RI
N rec = ((YPN-YP0) * Grain N)/ fertilizer N efficiency
Assumptions:
Grain N = 2.39%
Fertilizer efficiency = 50%
Max Yield = (local cap determined by the producer)
40. Optical sensor based algorithm for
Corn N fertilization
OSU Maize Algorithm
YP0=1291*(EXP(NDVI/Sum of GDD*2649.9) V8 to V12
RI = NDVI- N Rich Strip/ NDVI – Farmer Practice
YPN = YP0 * RI
N Rate = ((YPN – YP0)* 0.0125)/expected fertilizer use
efficiency
41. Extension: Oklahoma
More than 500, 000 acres in Oklahoma use N rich Strip
Producers have adopted this technology after seeing
the success of their neighbors
Use of GreenSeeker sensor has been a key in Oklahoma
Saving 10 $/acre (Either cutting N rate or gaining yield
by increasing N rate)
42. United States
N rich strip used for different crops rice, cotton, wheat,
corn soybean etc.
Louisiana Kansas, Nebraska, Arizona, Iowa Montana
Arkansas, Missouri etc. more than 35 US states are using
GreenSeeker sensing technologies.
43. Around the world
NGO’S effective for the extension
CIMMYT (Mexico, India, China,)
CIAT,CARE, CGIAR
OSU Nitrogen Fertilization Algorithm (Wheat and Corn)
are used in Argentina, China and India
USAID: Grant allowed GreenSeeker Sensors to be
delivered in China, India, Turkey, Mexico, Argentina,
Pakistan, Uzbekistan, and Australia.
47. N savings Using GreenSeeker In Yaqui
Valley, Mexico
Average wheat yield 2011-2012 : 7.2 t/ha
Average N rate 250 kg/ha
Savings: 68 kg N/ha
13.5 pesos/kg N= 918 pesos/ha ~ 70$/ha
While maintaining the same yield
By 2012 = 4000 ha
51. N Rich Strips guides to additional N application
Yield potential can be predicted in corn, wheat,
and rice (biomass produced per day).
Response to applied N is variable from year to year
and can be predicted.
N rate changes from year to year.
Nutrient removal is tied to yield level.
Need to account freely available N in our N rate.
Conclusion