adminTo begin with, the farmers need to know what foliar fertilisers are and why they should use them despite having enough conventional basic fertilisers in their stocks.
Foliar fertilisers are applied to foliage (leaves) to boost nutrient density in crops and to correct nutrient deficiencies.
The main benefit of foliar spraying is that it could have up to a 90 percent efficiency rate of uptake as opposed to 10 percent efficiency from soil applications.
Foliar fertilisers become immediately available in the plant because they are 100 percent water soluble, which makes them perfect for correcting nutrient deficiencies.
Soil amendments naturally take several days to take effect and the nutrients may be tied up with other elements and made unavailable to the plant.
“Foliar fertilisers can be quite effective and can stimulate plants to create exudates in the roots which excite microbes to work harder and thus increases nutrient uptake from the soil.
“Foliar sprays are a great supplement to boost flavours, sweetness, mineral density and yield from your crops.
“However, in spite of all these attributes, they cannot be used on their own but as supplements of basic fertilisers. Their role is to augment low nutrient rates of basic basal fertilisers. They are there to supplement micro-elements such as zinc, boron and molybdenum,” acting director Agritex Crop Research Division, Mr Victor Chingwara, said.
He said farmers have to be informed on the use and application of the fertilisers lest they created more problems from using them incorrectly.
“They must be diluted correctly with strict adherence to the manufacturer’s instructions. They may cause abnormal growth if applied excessively and may even turn phytotoxic and burn leaves if wrongly mixed,” he said.
Farmers, said Mr Chingwara, must therefore have samples of leaves taken from their fields to establish the nature and quantity of foliar fertilisers they need before applying them. They come in different versions. Some are for coffee, fruits, vegetables or conventional crops.
He added that foliar fertiliser must not be applied to stressed crops as such as those with closed stomata through which the fertiliser is expected to enter the crop.
Windmill Fertiliser Company crop chemical manager Mrs Caroline Charumbira said foliar fertilisers were crucial as they provided micro or trace elements that are not always available in basic fertilisers. We produce Nutrifor 1, 2 and four types of foliar fertiliser. A litre of Nutrifor 1 can cover a hectare while 1, 2 litres of Nutrifor 4 also cover a similar hectarage,” she explained.
She added that they taught farmers on how to use the chemicals upon buying them to avoid cases of incorrect use.
A marketing executive with Zimbabwe Fertiliser Company, Mr Justice Chamuka, said they produced Foliar 15.
“We have agronomists stationed in all parts of the country to educate the farmers on the use of foliar fertilisers and other agro-chemicals for good results. Farmers need to know that foliar fertilisers are used merely as supplements so they have to buy basic fertilisers to give plants a complete package,” he explained.
If soil pH limits nutrient availability and ground applied fertilisers are not taken up, foliar fertilisers may be a valid option.
In this case, a soil sample should be taken to determine pH and a leaf tissue sample taken to determine the need for additional foliar fertilisation. In some cases poor root health from compaction, replant disease, crown rot, mouse damage, water logging or other problems may warrant foliar feeding of plants.
Tests have shown that foliar feeding could increase yields from 12 percent to 25 percent when compared to conventional fertilisation.
Online Reporter