THE COST OF
n tough times producers usually try to
save costs by deferring pH rectification.
The soil pH plays an important role in the
ultimate yield of crops. Figure 1 provides
a comparative analysis of average yield (t/ha)
and pH(KCl) on a land of maize under dryland
Figure 3 provides insight into the loss/non-
availability of plant nutrients at different pH levels.
Figure 3 depicts the fertiliser loss as between 53.7%
and 32.7% if we use the same starting point of 4.8.
If we assume a fertiliser loss of 32.7% at an average
fertiliser cost of R2 500 per hectare, R817.50 per
hectare will have been sacrificed. We can derive
that the total cost of low pH levels and the lack
Esmond Coen from Grasland
of applying lime will cost the producer at least
R1 702,50 per hectare in yield loss.
Grasland provides its clients with the opportunity
to have the pH rectification costs financed over a
period of three years. This will help producers to
improve their cash flow and to reap the benefits of
improved crop yields.
Evaluate the following scenario where the soil
pH(KCl) is 4.8, which would need approximately
2 tons of lime per hectare to elevate the pH to
5.2. The average cost of lime is R230 per ton and
the average cost of delivery is R150 per ton. The
average cost to have it spread on the land is R125.00
for up to 2 tons. The total cost to have it delivered
and spread would amount to R885 per hectare.
With a yield increase of just 1 ton of maize, and
an approximate maize price of R2 000 per ton, it is
obvious that there is a definite advantage to rectify
a low pH level to a more favourable pH level.
Figure 2 indicates that the net benefit is a return
on investment of more than 125%. The pH level
will sustain cropping for the next season and the
producer will still profit from the rectified pH level
with the increased yield.
The benefits of rectifying the pH level do not end
there - the plant nutrients in the soil also become
more available to plants. This means that fertiliser
can be used more economically and efficiently.
Increase in yield
Return on investment
Graslander Maart 2017