Researchers here in Kenya have established a link between the potentially harmful Aflatoxins, and poor crop health and nutrition in maize. Improved soil fertility, agronomy and soil testing can all help reduce levels of this carcinogen in grain.
Aflatoxins are produced by a fungus which thrives on maize crops in poor health, and the recent trials published in Field Crops Research Journal showed how maize grown without sufficient Nitrogen produced higher Aflatoxins at harvest. But Nitrogen uptake is influenced by other factors. “Phosphate, soil pH, soil structure and compaction all impact Nitrogen uptake in the crop” according to CropNuts Agronomist David Jones. Getting all these other factors right by carrying out a soil test, and digging a soil pit in your shamba will all help improve yields as well as the safety and quality of the grain.
“We often find that maize growers are not using enough fertiliser to achieve optimum yields, but sometimes more Nitrogen fertiliser isn’t the answer. If soil compaction is restricting root growth, cultivation with a chisel plough can open up the soil and improve nutrient uptake”.
Plant health is also improved by limiting pest damage, so a carefully timed insecticide to control Chafer Grubs, Cutworms or Thrips for example can protect yields and grain quality. “Agronomy advice from an independent source will ensure that inputs are only used when necessary, to avoid excess costs. The appropriate fertilisers and sprays are also selected for the particular farm situation, rather than what the Agrochemical supplier has on their shelves at that particular moment”, explains Mr Jones.
“CAN for example is actually very expensive per unit of nitrogen compared to Urea because it contains just 28 units of N compared to 46 units in Urea. And contrary to popular belief, the liming effect of CAN is minimal. Save the money, and invest it in an appropriate liming program!”