Senwes Scenario December 2016 / January 2017 | Page 23

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T RA D E N E W S ••

moisture content, mechanical
resistance, soil chemistry, organic material, alkalinity, KUK,
plant-available water retention
ability, soil depth and hydraulic
conductivity.
2.4 Crop variables
Crop density, plant height, plant
nutrition (N, P, K, Ca, Mg, C,
Fe, Mn, Zn and Cu); plant water
congestion, plant biophysical characteristics, leaf area index (LAI),
interception, photosynthetic active
radiation and biomass; plant leaf
chlorofil content and grain quality.
2.5 Other variables
Weeds, insect infestation, nematodes, diseases and mechanical
damage due to weather conditions.
2.6 Management variables
Tillage, fertilisation, crop rotation,
application of herbicides, irrigation, etc.
MANAGEMENT AND PROFITABILITY
OF VARIABLES
Precision farming record keeping
will allow the farmer more accurate application of fertiliser and
chemicals, which will decrease
input costs and increase yields.
A more practical explanation is
that precision farming allows the
manager to note and change farming activities in a more accurate

manner. It is known as the management of variables. The management of variables can be done by
means of a map-based approach or
a sensor-based approach.
The map-based approach is normally easier to apply and is based
on the following:
• Timetable-based random sampling of the field
• Laboratory analyses of the soil
• A specific map of soil types,
yield, etcetera, of a field
• Using this map-based approach
to apply variable rate application.
The sensor-based approach
concentrates on the direct plant
and soil characteristics to a larger
degree and is based on the following::
• Real-time sensors
• Using real-time sensors, which
are physically placed in the
field, in order to apply variable
rate application.
The use of these methods, irrespective of the approach which
can be followed, offers a reliable
instrument for the assessment
of agricultural risk as well as the
scheduling of every-day farming
activities.
The direct economic benefits
which relate to the application of
precision farming on farm level

are normally difficult to calculate.
For this reason it is of the utmost
importance to measure the profitability which precision farming
can pose on a total farm basis
and not as individual operational
units. This means that all the
farming units and resource limitations where precision farming is
applied, will have to be taken into
account. In this manner the use of
precision farming technology will
indicate possible profit maximising
potential, as well as the potential
to decrease risk.
Farmers can do an economic
analysis, based on the variation of
crop yield, in order to obtain an
accurate determination of risk. For
example, the farmer can determine
that 70% of the time 75% of the
oats on a specific field will deliver
a yield of 3,8 tons per hectare. If
the farmer is aware of his input
cost per hectare, a more accurate
profit margin per hectare can
be calculated beforehand. These
benefits go hand in hand with
the accurate record-keeping made
possible by precision farming technology.
For further information, contact
Vossie by email at lfvanstraaten@
gmail.com
* Vossie van Straaten is a masters
degree student in Soil Science
* Luan van der Walt is an economist
at Grain SA

SENWES Scenario • DEC 2016/JAN 2017

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