Variable-rate nitrogen fertiliser applications are paying dividends on farms across Africa by building up poorer land and improving production in the better areas.
One example of the success I've seen on my travels is with G&M Farming Enterprises, a fifth-generation family farming business near Middelburg in the Mpumalanga province of South Africa.
Gareth Allen, one of the fifth generation, told me they drill a total of 1,700ha (4,200 acres) on a rotational cropping system, two-thirds maize and one-third soya beans.
Precision spreaders with rate control
It is clear that specialised mechanisation and precision farming play big roles in their set-up. They use Case IH tractors, a 24-row Massey Ferguson 9800 planter and tined rippers (subsoilers) from Radium Engineering.
Fertiliser and lime is spread via Radium precision spreaders with rate control, using a Raven precision system. Variable-rate spreading of fertiliser and lime using RTK, has been part of G&M’s husbandry system since 2004.
This has helped them to build up the soil fertility in weaker areas and maintain it in the better areas using granular phosphorus and potassium mixtures and agricultural lime.
Michael Allen, Gareth Roest and Gareth Allen
Allen's standard approach consists of a flat rate of NPK granular fertiliser mix, spread before planting, then, with the planter a liquid application is made.
A further dose of mainly liquid nitrogen is done with an inter-row sprayer early in the maize growing season.
Improved soil fertility and yields
While Gareth admits his costs per hectare have increased using this system, he is seeing yield benefits by building up the soil fertility with selective fertilisation and improving the soil structure by the use of rippers.
He reports much larger yields with dry-land maize and these yields are still increasing.
By using bigger tractors and farming more precisely, the family has increased efficiency and provided more effective use of fertiliser, chemicals and especially diesel.
And this goes to show how precision farming can benefit farmers in South Africa.