Advice from a successful organic raisin producer

Gawie Steyn, an organic raisin producer of the Orange River Valley, has proved that organic production can be commercially viable. He spoke to Glenneis Kriel about his production practices

-  Glenneis Kriel

When Gawie Steyn, who farms near Kanoneiland in the Northern Cape, decided to switch to organic raisin production in 2008, his greatest initial challenge was to obtain enough organic material as soil cover.

Soil cover, he explains, is needed to reduce evaporation, which in turn improves the efficiency of flood irrigation and makes it easier to keep the top 20cm of soil saturated. This is important for farmers along the Orange River, as they take turns to irrigate their vineyards, which means that some receive water only every second week.

The soil cover also helps to buffer the soil against extreme temperatures, thereby encouraging the growth of a diversity of micro-organisms important for soil health and mineralisation.

Initially, Steyn considered buying straw or chaff to spread under the vine rows, but was unable to obtain any that was organically produced. He therefore made do with weeds already growing in the vineyards, but this failed to produce good results due to the hot climate.

“Our summer temperatures range from 22°C up to 42°C or higher, so the weeds decompose within a few days after being slashed and thrown onto the vine rows.”

LUCERNE 

In 2014, Steyn decided to opt for lucerne as a cover crop between the vineyards.

“Lucerne is a clear winner under our conditions because it’s a perennial crop, it produces plenty of dry matter, and it’s a legume, which fixes nitrogen through symbiosis with rhizobium bacteria.

“Having flood irrigation also lessens competition for water between the vines and the lucerne.”

In addition, a perennial crop reduces cost, as the plants don’t have to be re-established each year, and there is less interference with the soil.