Farmers, who apply lime regularly into soil to reduce acidity, increase the efficiency of fertiliser nutrient availability for crop utilisation by more than 90 per cent.
This reduces fertliliser wastage besides increasing yields.
Application of the required fertiliser rations can still lead to low productivity if the soil is acidic, a factor that significantly reduces the availability of macro and micro nutrients to the crops.
According to a research done by One Acre Fund, a non-profit social enterprise working with more than 500,000 smallholder farmers in Sub-Saharan Africa in 2015, soil acidity is a major constraint to agricultural productivity throughout in the continent with an estimated 15 per cent of all agricultural soils affected by acidity.
The research however, reveals that in 2014, a 14 percent maize yield increase was found when calcitic lime was applied in the maize seed holes at planting at a rate of 0.5 t/ha in Bungoma South.
In Kenya, a 25 kg of lime is sold for at Sh200 with instructions to apply the lime to 0.3 hectares of land, microdosed at planting with seed and fertilizer application.
Nyamira farmers applying lime to their farms to reduce soil acidity and increase yields. Farmbiz Africa.
A soil PH of 4.5 for instance is highly acidic. According to Timothy Munywoki, an Amiran Kenya agronomist, only 30 per cent nitrogen will be available for crop use in such soil.
“If the PH is 7.0, which is the neutral state, more than 95 per cent of the nitrogen from fertilisers is available to crops,” said Munywoki.
About 20 per cent and 30 per cent of phosphates and potassium are respectively available in the 4.5 soil PH. Cumulatively, 70 per cent of the NPK fertiliser is wasted, leading to low yields even at optimum crop husbandry.
Major causes of soil acidity or the loss of the alkaline elements and compounds is by leaching due to plenty of water from flooding. Decaying matter, repeated growing of legumes like alfafa and clovers also depreciates the alkaline components of the soil, therefore, causing acidification.
Various liming agents are used to restore the soil PH gradually for up to two years.
But Amiran Kenya has introduced EcoGRL, a product that restores the PH of soil within six months.
“The EcoGRL has smaller granules than most commercially available products, a property which increases the surface area of interaction with soil particles for a quick restoration,” said Munwoki.
The liming material contains 39.6 per cent calcium, 87.3 Calcium Carbonate, 1.13 per cent magnesium, 3.27 magnesium carbonate, 0.97 iron (III) oxide and 0.19 of potassium oxide.
Soils in Nyanza, Western, Rift Valley and Central parts of Kenya have a PH of less than 5.5 because of frequent use of nitrogenous fertilisers in form of ammonium.
On average, crops require PH range of 6.0 – 7.0 for optimal growth. However, different crops have various degrees of tolerance to acidity. Chillies, sweet potatoes and Irish potatoes are tolerant to acidity. They can do well in soils with PH values of below 5.5. But most horticultural crops cannot survive such acidity; they require PH values of between 6.2 and 7.4.
Maize tolerates 5.5-6.0 PH
The EcoGRL can be applied singly or in a mix with other granular fertilizes at a rate of between 40kg per acre and 60kg per acre. The variation is determined by the intensity of the alkaline depreciation.
Munywoki can be contacted on +254728853914.