Graslander Uitgawe 3: Nampo - Page 6

ARTICLE THE COST OF SOIL ACIDITY I 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 conditions. 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. Amount Price R230.00 2 R150.00 2 R125.00 1 Total R2 000.00 Increase in yield 1 Costs Profit Return on investment Item Lime cost Delivery cost Lime spreading Figure 2 4 Graslander Maart 2017 Figure 1 Total R460.00 R300.00 R125.00 R885.00 R2 000.00 - R885.00 R1 115.00 125.99% Figure 3