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Precision Farming is the agriculture of today and the
future. The discussion below explains the process in detail.
From Mules to Satellites: A Discussion of
Precision Farming
By
Steve Crouch, President of NCI
Agriculture in the United
States has evolved literally from mule-drawn implements to
satellites in the 20th century. It is intriguing to
imagine what developments will come in the current century.
Why did technology become so
important to agriculture? Reasons come first, and answers come
second. Farm producers are stewards of the land and are
environmentally friendly for three reasons:
First, Producers want to make a profit on their investment, while
feeding and clothing their families. They must maximize their
yields while minimizing their expenses through informed decisions
Second, No one is making land. Therefore there is no additional
land available for arable use. In fact the best arable land
continues to be lost to homes and manufacturing.
Third, Producers have a genuine love of the land and enjoy the
accomplishment of feeding our Country and the World. They take
pride in the fact that less than 10% OF OUR INCOME GOES TO FOOD
LEAVING THE BALANCE FOR OTHER CONSUMER.
Today’s producers are forced
to maximize potential while faced with decreasing margins.
Therefore they need new answers to meet their reasons of a profit,
maximize yield on available land, and pride in accomplishment of
supplying food and fiber at a cheap cost to the consumer.
Over the past 10 years the answer has changed as
profits dwindled and cost continued to rise. Never has there been
a greater need for the facts on how to produce a profitable crop
with fewer inputs. What are the answers to best maximize their
potential? Just as a manufacturer producing a product must know
the cost and inputs on a production item, the farmer must now the
facts to insure a profit. To answer this question a technology has
evolved. That technology is known as Precision Farming.
Precision Farming
Precision Farming is a multiple step process that
requires study and discipline. The process brings many layers of
information in to play for one purpose. That purpose is to have
our producers achieve their reasons to farm in an environmentally
safe and cost effective method.
Now how do we use Precision Farming? Precision
Farming generates large amounts of facts called GIS. These facts
are only useful if tied to a location called Global Positioning
System or GPS. You must understand and use both components of
Precision Farming to make a successful system.
Geographic Information Systems - GIS
Facts are collected to build history and insure a
better crop while controlling inputs. A producer will look for
facts on where the highest yield was produced as well as each
zones production, and he will gather facts on soil types, pull
soil samples, look for management zones to generate prescription
maps for variable rate applications, and use aerial photography.
This fact gathering is not trivial and requires
time, money, good computer skills, good organization, and
willingness to learn. These facts are put into a system that is
known as Geographic Information Systems or GIS. Each one of these
facts would represent a layer of information. These layers yield
mapping, soil imagery to identify zones, soil sampling and
variable rate application of fertilizer and pesticides all
represent facts used to reduce inputs and improve profits. All of
the GIS layers are only useful when associated to a location. The
location is recorded through Global Positioning System or GPS.
Global Positioning System - GPS
GPS is a satellite-based global navigation system
created and operated by the United States Department of Defense
(DOD). Originally intended solely to enhance military defense
capabilities, GPS capabilities have expanded to provide highly
accurate position and timing information for many civilian
applications.
Simply stated, twenty-four satellites in six
orbital paths circle the earth twice each day at an inclination
angle of approximately 55° to the equator. This constellation of
satellites continuously transmits coded positional and timing
information at high frequencies in the 1500-megahertz range. GPS
receivers with antennas located in a position to clearly view the
satellites, pick up these signals and use the coded information to
calculate a position in an earth coordinate system.
GPS is the navigation system of choice for today
and many years to come. While GPS is clearly the most accurate
worldwide all-weather navigation system yet developed, it still
can exhibit significant errors. GPS receivers determine position
by calculating the time it takes for the radio signals,
transmitted from each satellite, to reach earth. It’s that old
“Distance = Rate x Time” equation. Radio waves travel at the
speed of light (Rate). Time is determined using an ingenious code
matching technique within the GPS receiver. With time determined,
and the fact that the satellite’s position is reported in each
coded navigation message, by using a little trigonometry the
receiver can determine it’s location on earth.
Position accuracy depends on the receiver’s ability
to accurately calculate the time it takes for each satellite
signal to travel to earth. This is where the problem lies. There
are primarily seven sources of errors that can effect the
receiver’s calculation. These errors consist of:
1.
Atmosphere delays on the radio signal
2.
Signal multi-path
3.
Receiver clock biases
4.
Orbital satellite position errors
5.
GPS satellite errors
6.
Tracking biases (position shifts when
satellites are lost and re-acquired)
7.
GPS Receiver performance and cost
The combination of these errors and poor satellite
geometry can limit GPS accuracy of a high performance GPS Receiver
to approximately 5 meters and a low cost GPS Receiver to 10-15
meters. Many of these errors can be reduced or eliminated through
a technique known as “Differential”.
Differential GPS or DGPS
DGPS works by placing
high-performance GPS receiver (reference station) at a known
location. Since the receiver knows its exact location, it can
determine the errors in the satellite signals. It does this by
measuring the ranges to each satellite using the signals received
and comparing these measured ranges to the actual ranges
calculated from its known position. The difference between the
measured and calculated range is the total error. The error data
for each tracked satellite is formatted into a correction message
and transmitted to GPS users. The correction message format
follows the standard established by a Special Committee. These
differential corrections are then applied to the GPS
calculations. The level of accuracy obtained is a function of the
GPS receiver. There are two other types – Signal Beacon including
Omnistar, a satellite based subscription fee service and WAAS, a
satellite based free signal.
Now with a location, how do we use the information?
Applying Precision Farming though equipment
Newton Crouch Inc. offers control of one of these
layers through an on board computer system in an application unit.
This system is made up of a controller and GPS receiver, radar,
and input sensors. The controller system allows the operator to
monitor many factors while maintaining a constant flow of material
over various speeds. Furthermore, the system will locate a
management zone and vary the rate to that specific zone on the go.
The material spread can be granular or blended fertilizer, lime,
land plaster, slurry, clear liquid fertilizer, or litter.
Depending on the product, it can be spread, applied, or injected.
The controller is simply operated by using its
components. The controller is the brains of the unit. The
controller maintains the application rate or varies the rate as
need be to achieve the desired rate in that location. The GPS
receiver gives it a sub meter location, the radar gives you a
reference speed, and the input sensor gives a reference to the
application amount in Pounds/Acre as an example.
The controller requires the operator to input 6
facts then generates the following:
1.
Pounds/ acre applied
2.
Acres cover
3.
Acres in the current field
4.
Pounds applied as a total
5.
Pounds left in the applicator
6.
Speed
7.
Precise guidance
8.
Real time reporting
9.
Records an as applied map on PC card
10.
Verify location to start
application
11.
Spot spray applications
12.
Scouting for problem areas and
identifying areas.
13.
Marking for hazards
One of these components has received wide
acceptance. The component is the Guidance system. These systems
can help reduce application error by maintaining a distance called
a swath. This component can also give an applied map and
navigation.
Precision Farming is evolving. The concept has
formed into a different process than originally thought, as more
has been learned. Rather than looking for the best system,
Precision Farming is looking for marginal increase in a number of
areas. But we must always remember the number one limiting factor
is water.
Precision Farming is helping producers do a better
job at planting and to be better stewards of the land. NCI can
help you use Precision Farming by providing you with the equipment
to do the job and the training to use your equipment to its best
advantage. Contact us for details at 770-227-1234. We look
forward to serving you.
To learn more or inquire, please
visit the Contact Page.
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