nitrogen management using optical sensor , precision agriculture

1. Presented by:
Tanmoy paik
16AGR20
Supervisor:
Prof. Yashwant Singh
DEPARTMENT OF AGRONOMY
I.A.S., B.H.U.
M.Sc.(Ag.) Agronomy Course Seminar

2. INTRODUCTION
• To feed the ever increasing population we need to produce more.
• Nitrogen is the most limiting factor for crop production, next to the
water.
• Soil system don’t contain Nitrogenous mineral.
• Nitrogenous fertilizer production is costly, high energy requiring, and
it is subjected to various losses.
•Successful nitrogen management can optimize crop yields and
increase profitability, and minimize nitrogen losses to the environment.
• With the progress of science when we are thinking about Green-
energy, sustainability, and environmental safety, we should have a look
on modern nitrogen management tools.

3. N is an essential constituent of enzymes,
chlorophyll, nucleic acids, storage proteins,
cell walls, and a vast array of other cellular
components (Harper, 1994) .
Nitrogen is the nutrient that most often limits
crop production. (Pathak et al., 2005)

4. Worldwide nitrogen use efficiency for cereal grains
and row crops estimated at only 33 %.
(Raun and Johnson, 1999).
• Unaccounted 67 % represents loss of fertilizer N.
• N:P:K ratio in INDIA is 6.7 : 2.7 : 1.
(Indian Journal of Fertilizers, 2017)
Where ideal recommendation is 4:2:1

5. Nitrogen kg/ha
Spatial variability in Nitrogen use under RWCS
In wheat
In rice
Nitrogen kg/ha

6. Modern technology rely on real time observation
measuring actual requirement of crop.
Sensor-Based Approach Recognition
 Named “the most revolutionary approach in a century to
fertilizing crops” - the U.S. Department of Agriculture
 Voted "the best and the brightest developed throughout the
world for the agricultural, food, and biological systems
industries" -American Society of Agricultural Engineering

7. Sensor can detect
•  Plant Biomass
•  Plant Chlorophyll
•  Crop Yield
•  Water Stress
•  Plant diseases, and
•  Insect damage
 Sensors are used by agronomists, breeders,
plant pathologists, weed scientists, crop
consultants.

8. SOME MODERN TOOLS
• Leaf Color Chart (LCC) ,
• Soil Plant Analysis
Development Meter
(SPAD)
or Chlorophyll Meter ,
• GPS, GIS & VRT .
• GREEN SEEKER ,

9. What is GreenSeeker ?
• Green Seeker is an integrated optical sensing , variable rate application &
mapping system that measures crop's nitrogen requirements.
• Yield potential for a crop is identified using a vegetative index known as
NDVI (normalized difference vegetation index) and an environmental
factor.
• The technology was developed at Oklahoma State University, USA and
licensed to N Tech Industries in 2001 (http://www.ntechindustries.com).

10. • It offers a more efficient and precise way to
manage crop input i.e. nitrogen.
• Nitrogen (N) recommendation based on yield
potential and the Response Index (RI).
• The Green Seeker estimates the right amount
of N at the critical stages of crop growth.
GreenSeeker

11. Handheld
type
Mounted
type
Types of
GreenSeeker

12. How does the sensor work?
• The sensor uses light emitting diodes (LED) to generate
red (660 nm) and near infrared (NIR) (780 nm) light.
• Red light is absorbed by plant chlorophyll as an energy
source during photosynthesis.
• Healthy plants absorb more red light and reflect larger
amounts of NIR.

13. Basic Sensor Specification
• GreenSeeker sensors have 24 inch (approx.)
field of view.
• Each sensor gives 10 output readings per
second.

14. What is NDVI ?
• Normalized Difference Vegetation Index (NDVI) is
commonly is used in green seeker. (Rouse et al., 1974)
• NDVI =
(𝑁𝐼𝑅 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑 − 𝑅𝑒𝑑 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑)
(𝑁𝐼𝑅 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑 + 𝑅𝑒𝑑 𝑟𝑒𝑓𝑙𝑒𝑐𝑡𝑒𝑑)
• NDVI readings can range from 0.00 to 0.99; the higher the
reading, the healthier the plant. The value 0 represents an absence
of vegetation.

15. N-Rate Calculator on-line
www.nue.okstate.edu
Algorithm based N calculator in Excel
Oklahoma State University, and CIMMYT

16. • Yield response to additional N for each field environment.
• RI=N responsiveness.
• RI =
Grain yield N rich
Grain yield check ( 0 − N )
• In season RI =
𝑁𝐷𝑉𝐼 𝑜𝑓 𝑁 𝑟𝑖𝑐ℎ 𝑠𝑡𝑟𝑖𝑝
𝑁𝐷𝑉𝐼 𝑜𝑓 𝑡ℎ𝑒 𝑓𝑖𝑒𝑙𝑑 𝑟𝑎𝑡𝑒
• RI changes each year.
(Long term corn exp.,
1971-2010,nabraska)

17. Misconception 1: “GreenSeeker is a Nitrogen Sensor ’’
Facts: GreenSeeker is a biomass sensor
Nitrogen leaf content is not a good predictor of yield potential
Biomass/color is highly correlated with yield potential
Misconception 2: “I can see variability with my eyes—
I don’t need a sensor”
Facts: We can see macro variation in a field, but not subtle changes
We cannot remember where the variations are and to what degree
Misconception 3: “If you give me your yield goal, I’ll tell you
how much nitrogen to apply”
Facts: “Yield Goal” fertility is a not the best approach economically and
environmentally
You can’t estimate mineralization rates, residual N, or lost N without in-
season information.

18. Why not use ambient light instead
of an active LED light source?
• The sun's intensity is affected by sun angle,
cloudiness, time etc. causing inconsistent NDVI
measurement.
• Active sensor generates its own illumination,
• And function in nearly any condition including
darkness.

19. • A nitrogen rich strip
necessary for calibration.
• This amount is be higher
enough ,crop & region
dependent.
• 300 to 500 feet long ,
representative of the
field.
• As in 2011 the software
has been upgraded so a
nitrogen rich strip is no
longer required,
• Used for a crop specific
algorithm.
Kg/ha.

20. Display Screen
Easy-to-read display—
even in sunlight
Trigger
Simple pull-type trigger
to take observation
Functional Parts Of A GreenSeeker

21. Sensor
High-quality optical
sensor instantly
measures plant vigor
Micro USB Charging Port
Provides a direct connection to recharge
the handheld without the need to remove
and replace the battery
Battery
Long-lasting
rechargeable battery

22. Suitable Crops
• Algorithms have been developed for wheat, rice
and maize.
• Researchers are working on algorithms for
potatoes, sugar beets, sugarcane, barley, cotton
and sunflowers.
Any time of day & night.

23. Number of samples per plot
• One per plot of a fixed duration (depending
on plot size);
e.g., approximately 5 seconds for a 5 m plot.
◦ any developmental stage and/or
◦ at regular intervals from the emergence to
physiological maturity,
◦ or depending on the experimental objectives

24. Height of reading
• NDVI readings taken at different heights above
the crop canopy remain constant.
• The computation is actually a normalized ratio.
• Even it moves farther away from the crop
canopy, the sensor proportionally adjusts and
therefore, NDVI readings are not affected by
height variance.
• Optimal sensing height is 32-48 inches above the
plant.

25. The sensor's field of view is an oval;
It widens as the height increases.

26. Procedure of reading
Plot border
Sample area
Area measured
(A) FIeld map and direction of measurement,
(B) Area sampled within each plot.

28. Evaluation of GreenSeeker optical sensor-based N
management in wheat at Ludhiana, India
Cultivar Treatment kg N ha-1 Total N
(kg ha-1)
Grain
yield
(t ha-1)
Total N
uptake
(kg ha-1)
basal /at
planting
1st
irrigation
2nd
irrigation
PBW550 T1: No-N
control
0 0 0 0 1.83 37.1
T2: 60 60 0 120 4.01 99.6
T3: 30 45 12
*GreenSe
eker-
guided
88 4.00 88.1
T4: 45 45 13
*GreenSe
eker-
guided
103 3.97 89.5
LSD(0.05) 0.123 2.24
Bijay Singh et al. 2006-09

29. Evaluation of GreenSeeker optical sensor based N
management in wheat cultivar DBW 17 at Ludhiana, India
Treatment (kg N ha-1) Total N
( kg ha-1)
Grain
yield
(t ha-1)
Total N
uptake
(kg ha-1)Planting 1st irrigation 2nd irrigation
T1:
No-N
control
0 0 0 0 1.80 35.8
T2: 60 60 0 120 4.01 93.6
T3: 30 45 12
*GreenSeeker-
guided
87 3.92 86.4
T4 45 45 13
*GreenSeeker-
guided
103 4.01 90.2
LSD(0.05) 0.123 2.24
Bijay Singh et al. .2006-09

30. Effect of nitrogen management in rice using GreenSeeker
optical sensor
Cultivar Treatment Total N
applied
(kg ha-1)
Grain yield
(t ha-1)
Straw yield
(t ha-1)
PR 118
No N , Control 0 2.16 3.06
RDF , 120 kg N / ha 120 4.82 7.24
GreenSeeker NDVI 0.80 as
threshold
75 3.99 5.18
GreenSeeker NDVI 0.85 as
threshold
105 4.79 6.32
GreenSeeker NDVI 0.90 as
threshold
105 4.69 6.45
Green Seeker based
algorithm approach
102 4.86 6.4
CD(0.05) 0.33 0.46
Puneet sharma , PAU, Ludhiana , 2010

31. Ratanoo et al. 2016
N at second and third irrigation was applied as guided by GreenSeeker optical sensor

32. Evaluation of GreenSeeker sensor based nitrogen
recommendations in winter wheat (Triticum aestivum L.)
Oklahoma State University, USA Walsh et al., 2013

33. Effect of Precision nitrogen management for rabi sweet corn
(Zea mays saccharata L.)
Treatment Fresh Cob
yield with
husk
(t ha-1)
Fresh Cob yield
without husk
(t ha-1)
Green
fodder
yield
(t ha-1)
Stover yield
(t ha-1)
Harvest
index
(%)
Control (without N application) 4.21 1.38 7.53 3.85 35.7
150 kg N / ha (30,45 & 60DAS) 15.65 9.48 19.84 9.51 44.1
LCC based N at threshold 4 13.26 7.93 16.23 8.14 45.1
LCC based N at threshold 5 15.21 8.13 19.03 9.01 44.4
Green seeker based NDVI at
0.6
11.84 6.17 16.12 7.57 42.1
Green seeker based NDVI at
0.8
14.4 8.15 18.33 8.88 44.0
SPAD based N at threshold 40 12.48 7.81 16.72 7.62 42.8
S.Em± 0.58 0.47 0.75 0.39 0.20
C.D. (p=0.05) 1.73 1.41 2.24 1.08 5.9
Mallikarjuna et al, 2016

34. Advantages
• Simple , fast and non-destructive
• Easy to install, easy to calibrate,
• Real time data,
• Low labour requirement,
• Can be used with existing rate & control systems,
• Works in any weather condition— day or night.
• Can apply with or without the GPS signal.
• Do not rely on historical information or mapping,
• Distinct management zones within the field can be
identified.

35. LIMITATIONS
• High initial cost.
• unconventional.
• Calibration required.
• Technical knowhow is required.
• Majority of farmers are marginal and small.
• Sensor do not work properly–
-When crop is too young or near maturity.
-Do not differentiate between weed and crop.
-in transplanted rice in early stages

36. Conclusions
• Large field-to-field variability of soil N supply and consequent crop
yield variability are major concern in post green revolution era.
• Technologies that maximize production, preserve the environment,
and feed the world need to be implemented.
• The GreenSeeker estimates the right amount of N required at the
critical stages of crop growth and save N without yield penalty.
• Therefore GreenSeeker is the tool to identify, analyze and manage
variability within fields for optimum profitability, sustainability and
protection of land resources .
• There is a great scope of GreenSeeker based nitrogen management
both at farm level and institution level for further research.

37. Thank you