Winter Crop Imaging
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Agroview Crop Imaging and Management Service.
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Variability within Australian crops has
a significant impact on yields, profitability and industry
sustainability. At ground level variability is difficult
to assess. However, infrared images collected using airborne
or satellite sensors readily show crop variability. The
images show where to sample crops and identify differences
within individual paddocks and across farms.
Growers and agronomists have the opportunity
to investigate the causes of the variability and implement
field or management strategies to improve crop uniformity
and yield and profitability.
While highlighting differences within
crops and pastures has been the primary use of remote sensing
to date, the ability to estimate actual parameters such
as biomass, moisture stress, yield, quality, specific nutritional
status, weed distribution or diseased areas are rapidly
emerging applications. In addition to these in-season uses,
remotely sensed imagery collected over a number of seasons
is a powerful tool for determination of production zones.
Click on image to view enlargement
Processed satellite imagery showing
relative crop stage across a farm
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to view enlargement
Crop vigor index derived from
SPOT imagery for a rice field. Following
tissue analysis for nitrogen content, nitrogen was applied
a different
rates across the field
A Standardised crop vigour index
of a cotton crop in
Dec and Jan using SPOT satellite imagery
Grower experience has demonstrated
the extent of crop variability shown by typical fields and
its significant impact on crop yield. Identifying this variability
using crop imaging has enabled growers and agronomists to
target crop sampling and when justified, develop and apply
variable rate application plans for nitrogen fertiliser.
These plans have resulted in many
substantial yield improvements relative to conventional
uniform application strategies.
Image Processing. Working
with EADS Astrium, a subsidiary of the European Aeronautical,
Defense and Space Organisation, Terrabyte has developed
techniques for the processing of imagery that will clearly differentiate
between and within zones.
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Sample field vigour |
The information provided by the images
is being used to target further crop monitoring and investigate
areas that appear to have differing vigour. The images are not a diagnostic
tool – they can identify variation but not the specific
causes of crop variability.
“Ground truthing” and further
analysis using all available information may allow development
of a variable rate nitrogen application map.
There are many causes of crop variability
and good paddock history records, landforming maps, soil
testing results, previous crop information and detailed
in-crop observations will all assist the interpretation
process.
Images are provided
in 2 formats.
a) Field Vigour
Image.
Each field is presented as a 12 colour image
highlighting the within-field variability. The colours
will represent the high, average and low crop vigour for
that specific field with colours for one field, not
directly comparable to the same colours in another field.
This image is primarily used to develop a sampling strategy
for the individual fields.
b) Regional Index
A separate image showing all ordered
fields for an individual farm is also provided as a regional
index. This image shows crop vigour expressed as a scale
from 1 to 100 with a consistent, continuous colour scheme.
This will allow direct comparison of the growth between
individual fields within a region, even when imaged on
multiple dates.
This image also identifies the magnitude of variation. While
the field vigour image will display 12 colours for each
field, whether the crop is highly variable or relatively
uniform, the regional index represents the actual crop vigour
value.
Click on images to view enlargement
Paddock Vigour |
Regional Index |