Variable-rate technology raises farm profitability

Unlike the broad, flat areas of South Africa’s Free State province, the Bergville area under the Drakensberg Mountains is undulating. Consequently, there is wide variation in soil types and production potential.

Mr Reitz told me he was exposed to precision farming when he spent time in the US about 12 years ago to study agriculture.

He says the first step to improving productivity on the farm in Bergville was using technology to record yields by area and create a grid so that specific areas – where deficiencies were detected by soil sampling – could undergo corrective treatment by variable applications of the necessary nutrients.

Subsequent study of yield maps showed that although overall production had improved, in some areas this was at the expense of profitability.

Adjust seed rates, row widths and fertilisation

The next step was to adjust seed rates, row widths and fertilisation so that the areas with the most potential got the treatment that would ensure extra costs were rewarded with profitable yields. At the same time, areas with low potential received lower inputs.

This was achieved by fitting the planter with a system to control variable seeding and fertilisation rates linked by GPS to the fertilisation plan created – with the help of the fertiliser supplier’s specialists – from the yield maps. This approach is beginning to show results and a significant improvement in overall profitability.

Nick Reitz monitor

Variable-rate control systems

The farm extends to 750ha, of which 350 are arable, with 280ha under centre-pivot irrigation. Double cropping is practiced with maize and soya in summer and wheat and cover crops in winter. A no-till regime has been in operation for a number of years. Farmers in the Bergville area are seen as the pioneers of no-till in South Africa.

The variable-rate control systems were fitted by a specialist local company to the farm’s existing New Holland “Early Riser” planter using separate electric motors to drive each row. This makes section control possible, as well as rate variation.

The farm’s trailed bulk lime and fertiliser spreader is also fitted with a variable rate and section control system. On lands under centre-pivot, section control is invaluable to ensure that expensive fertiliser goes where it will do the most good.