Farmer's Weekly (South Africa)
Groundnuts with a difference
32 years ago Growing groundnuts as an irrigated rotation crop with vegetables may be unusual, but it made plenty of sense to Flippie Buys of Weenen in northern KwaZulu-Natal.
Buys, who has been farming in Weenen since 1948, plants 100ha of irrigated vegetables and says his 32ha of groundnuts fits in well as a rotation crop. He has been growing groundnuts for many years, since the days of the Virginia Bunch, Natal Common and Egyptian Giant. Over the years he has retained his own seed and now plants a fair area to Egyptian Giant, together with Sellie. The other two original cultivars have high oil content, and variations in temperature caused the nuts to germinate underground and spoil the whole crop.
About four years ago, Egyptian Giant became popular among Indian consumers and Buys started multiplying some of the seeds he had kept. However, the demand for this special groundnut is very limited and corresponds with the limited supply of seed, he says. Most of the soils used for groundnuts have a sandy loam texture. In this area, the rainfall is relatively low, about 600mm a year, but all crops do well even in drought years if there is still enough water for irrigation. An interesting development in Weenen is that almost all the irrigation is now done by overhead sprinklers to conserve as much water as possible, and a lot less is used than in the days of flood irrigation.
Lands to be planted to groundnuts are ploughed in the conventional way. Then a seedbed is prepared using either Kongskilde-type tined implements or offset-disc harrows, depending on the amount of clods in the soil. When the soil is in a suitable state, tilth ridges are formed 750mm apart and as high as possible with a three-furrow share ridger. Superphosphate is then broadcast over the entire surface at a rate of 600kg/ha.
An implement is then used to split the ridges so the soil falls into the furrows between them, covering the fertiliser and forming shallow ridges. The seed is planted on the remaining ridges with a four-row planter fitted with jumbo seed bins. This system ensures that the seed does not come into contact with the fertiliser, which can be harmful.
The plant rows are 750mm apart and the seed is spaced 75mm apart in the row. Planting is followed by regular water application. After about one month, weeds are controlled with hand hoes.
Normally, because of the very high summer temperatures, about 40mm of irrigation water is applied every week. Egyptian Giant is harvested with a homemade tool bar fitted with a two-row lifter. This implement cuts the pods at the root when the groundnuts are still very soft and wet.
The wet nuts are gathered into bags and the stems and leaves are left in the windrows for baling. The picked wet nuts are collected daily by buyers from Durban, and sold to the consumer the following day.
The rest of the groundnuts are harvested in the usual way and cured in heaps before being picked and delivered to the Natalse Landbou Ko-operasie at Wasbank. A normal yield of unshelled nuts is about 3,7t/ha.
Fungus diseases are not a problem before the crop is two months old. After that, fungicides are applied with a tractor-mounted spray boom in five applications over the rest of the growing season.