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Introduction
Global Positioning Systems (GPS)
are a relatively new development and hold great promise for agricultural
use. Geographic Information Systems (GIS) in their simplest form have been
with us for a long time - simply information presented in a geographic
context - maps. New software designed to help manage the geographic
information allows for manipulation of data and the visual presentation of
different layers of information. These technologies offer unique
opportunities for better management of agriculture resources through
improved crop diagnostics, easy on-farm trialing and improved input
allocation.
Landscape Agronomy - The practice of agronomy on
a landscape basis requires the use of some sort of GIS. A simple form of
GIS is a drawing of the field or better yet an aerial photo of the field
which shows the field boundaries and relative location of pertinent
information such as yield, soil type, sloughs, significant landmarks and
sampling locations. A more advanced form of GIS is yield mapping which can
also show boundaries and locations of interest through the flagging
capability of the mapping software.
Simple ground control points
(a.k.a. photo stretching) - Handheld or more elaborate GPS
units can help develop GIS information in conjunction with aerial photos.
One of the challenges of using an aerial photo is placing geographic
points on the photo in order to see where the points are in relation to
other aspects of the field. A simple method of achieving the marriage of
GPS information and aerial photo information is by plotting the GPS points
in a spreadsheet such as XL and inserting a digital image of the aerial
photo as the background of the graph.
If points within the field
were collected with no reference to significant landscape features that
are visible on the photo you’re not much further ahead than having the
photo by itself. This is why ground control points should by marked with
GPS. The ground control points should mark features such as the road
intersections, driveways, corners of the field, sharp jogs in the field
boundary or other features that are visible on the photo. With the ground
control points you can now adjust the X and Y axis of the graph to get the
photo to fit the points. With the ground control points on the photo all
the in-field sample points will now be in the proper relation to the
photo.
Crop Diagnostics - GPS/GIS can be used
effectively in tracking areas of a field where crop diagnostic
investigations have been carried out. GPS allows the user to repeatedly
return to the same site for follow up assessment of crop growth or to
return to benchmark soil sampling sites. The location points can be merged
with yield map data to investigate correlations between observations and
yield.
Yield maps and on-farm trialing - The
introduction of yield mapping technology has made on-farm trailing much
easier. Treatment strips (fertilizer, varieties, fungicide etc) can be
laid out on the field and marked with GPS. Harvesting can be carried out
within the treatment areas and yield maps can show the effect of the
treatments. The data can be flagged in the mapping software and exported
to a spreadsheet program for further data analysis and
manipulation.
Input management - Crop production
inputs can be better managed through the use of GPS and yield maps. Some
diligent ground investigation coupled with yield maps can give insight
into productive capability of portions of a field. A better understanding
of the productive capability of various parts of the field and the reasons
for that productivity allows for targeted application of inputs such as
fertilizer or manure. Targeted input application can be achieved using GPS
controlled applicators or even with something as simple as a photo with
areas marked on it.
Conclusion
GPS/GIS concepts and tools
can assist with many areas of agricultural management. Improved crop
diagnostics is achieved by being able to return to the same location
throughout the season or by relating the diagnostic investigation to
landscape features. On-farm trialing and input management can be improved
through the use of GPS/GIS tools and concepts such as yield maps and
geo-referenced aerial photos.
Roger
Andreiuk
Reduced Tillage LINKAGES
4301-50 street, Leduc, Ab. T9E 7H3 |
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