The planting season is upon us. Farmers across the country are preparing their shambas for planting.
One of the most common crops to plant this season is maize. Maize is the leading staple food in Uganda and the East African region.
Many years of growing it on the same pieces of land has depleted soil fertility resulting in low yields.
Twaha Kakooza, a maize farmer in Kayunga district says much of the maize in Uganda is produced without productivity enhancing inputs; yields are generally below 1.3 tonnes per acre.
He says maize is also advantageous because it can be intercropped with other crops though yields are better when grown as a sole crop.
Although most maize farmers in Uganda have made an attempt to improve their yields from 600kg/acre to 1,200kg/acre, the yields can be much higher with good management and better practices.
Kakooza says high-yielding varieties need fertile soils. However, most soils have poor soil fertility so maximum yields can only be achieved by the application of organic or inorganic fertilisers.
Improve soil fertility
Rebecca Massa, the managing director Nissi-Agro-Vet says it is useful to seek guidance from an agronomist/soil scientist on the application of fertilisers. This is because the type of fertiliser depends on the soil type, soil nutrient deficiency and crop nutrient requirements, among other factors.
She says there are many other methods of maintaining and improving soil fertility like adding organic manure to the soils, improving drainage by breaking down hard surfaces, practice crop rotation, where a leguminous crop like beans is grown on the farm before maize is planted.
“Soil conditioning by liming or using acidic fertilisers may be appropriate to maintain soil fertility,” she adds.
Types of fertilisers
There are two types of fertilisers; organic and inorganic. Organic fertilisers are basically manure from decaying organic matter — plant and animal residues.
Benon Kisomose, an agronomist says inorganic fertilisers are minerals containing high quantities of plant nutrients.
He notes that the inorganic fertilisers provide specific chemicals, which may be lacking in the soil. It is advisable to use the correct type and method of application.
Good fertilisers must have nitrogen and phosphorus. Nitrogen can be obtained from urea, but also Calcium Ammonium Nitrate (CAN) and NPK supply other nutrients.
He says phosphorus is common in Diammonium Phosphate (DAP). Other sources of phosphorus include Single Super Phosphate (SSP), Triple Sugar Phosphate (TSP).
“When you see a bag of fertilisers with the initial NPK, know that it has nitrogen, phosphorus and potassium in equal measures,” he says.
How to apply fertilisers
Three methods are used to apply fertilisers. These are: broadcast, drill application and point application.
Broadcast is when fertilisers are applied over the area. This will benefit all crops in that area, including those planted with maize.
The drill method is when the fertiliser is applied in the seed hole, while the point application is when the fertiliser is applied in the vicinity or around the plant or under the seed in the same hole.
DAP, for example is applied in the seed hole, lightly covered with soils after which the seed is dropped in.
