Farmer's Weekly (South Africa)
Phosphate boost for maize
The results surprised this farmer, who is getting an extra ton a hectare and building up his soils fertility.
As a direct result of applying natural rock phosphate to his newly acquired maizelands, a Karkloof commercial-maize and fresh-milk farmer obtained an average of 1t/ha more grain than previously. Andrew Lund of the farm Triandra in KwaZulu-Natal bought an adjacent farm a while back, just in time for the 1985 planting season. These lands were planted to maize for some years. A soil analysis was taken and fertilisation done accordingly as had been past practice. But instead of using super phosphates to make up the P in the soil he decided to apply the natural rock phosphate Langfos. This was done at the rate of 500kg/ha. Lund’s late father, CL Lund, had for several years put down up to 1t/ha of rock phosphate on their commercial and silage maize lands. This had over a period built up the fertility of the soil and at the same time improved maize yields. Lund continued on these improvements of his father’s still using rock phosphate.
The 1t/ha increase over the previous year to 6, 5t/ha had surprised him; he did not think the increase would be so great after the first year of application. A total of 290ha of maize was grown in the 1985/86 season and on one block entered for the Ten-Ton Club he obtained an average 7,2t/ha. The yellow cultivars planted in 1985 and again in the 1986/87 season were Pioneer 6528 and 6514 much of the latter being used for silage and RS 50206. White cultivars were PNR 6405 AND 6429 and TX 382. Lund’s maize manager, John Campbell, says the level of P in the lands rose much faster compared to man-made phosphates. During the 1986/87 season he had hope to exceed his previous Top Ten yield with RS 5206. The stand originally earmarked for the completion had to be withdrawn as the seed obtained had been weevil-infested. There was also damage to the seed by rats.
He alleges this seed had been damaged by the pests before it had been treated chemically. He claims this was evident from the fact that the powdered chemical had adhered to the broken and damaged areas of the pips. Also he says it was the second year in succession that he had personally handled such damaged seed. Instead of entering this cultivar for the Ten-Ton Club, he decided instead on a block of Pioneer white
maize 6528. Fertilisation of the whole crop was a yield of 7t/ha. This season cultivar RS5206 will be used instead for silage.
Final seed-bed preparation is with a 3m wide, Kongskilde triple K, Vibro-Flex, high speed, stubble mulcher with Rotacrat. A four-row precision planter drills the pips in the rows 810mm wide and 250mm apart. This gives him a plant population of about 47 000 plants/ha. Fertilisation was 500 kg/ ha of 2:3:2 (zinc) in the row at planting. Immediately behind the planter a tractor and boom spray unit, with a 600ȟ chemical tank, sprays to control weeds and cutworm. It applies a cocktail-comprising decis for cutworm at a rate of 166m/ha; Gardomil at 5ȟ/ha for annual broadleaf control and lasso at between 3ȟ and 5ȟ/ha depending on the prevalence of nutgrass. Normally the maize for silage is planted in the first week of November while commercial plantings begin in September. The 1986/87 season started on September29. When the maize reached the six to seven-leaf stage, it was top dressed with 200kg/ha of LAN.
Just before it is due to tassel a further 100kg/ha of urea is sprayed on the crop by aircraft. The crop is also aerial sprayed for top grub by a chemical spray company that monitors the lands continuously through the use of traps. If there is a significant number of moths in the traps, the crop will be sprayed immediately to prevent a serious outbreak. Last year, harvesting of the silage crop began on March 4, giving a yield averaging 50t/ ha or 1600t from 40ha. This season the area to silage was increased. Campbell explains: “Each year we increase the amount of area to silage, yet it never seems enough.” This year however he believes they will have more than enough silage since the size of the Friesland herd has been reduced and a further 20ha of maize silage grown.
REDUCING THE HERD
Lund has reduced the herd from 250 to 230 and intends continuing to reduce it until only 200 cows are being milked at any one time. He anticipates he should ȱ ȱŘȹŖŖŖȱȱřȹŖŖŖȱȱȱ available for any emergency. His reason for reducing the herd is to enable more attention to be given to individual cows.
This article first appeared in the
13 February 1987 issue of Farmer’s Weekly and has been edited to adhere to the current style of the magazine.