By Umar Nsubuga
You cannot go wrong with onions. Onions can be produced on a wide range of soil types though heavy clay soils should be avoided as this may lead to bad aeration, crushing and blemished products of lower quality.
No cooking in Uganda is complete without onions, save in very exceptional cases. As such, onions have a ready market. With the right variety and proper management, an acre of onions can yield up to 23 tons.
Moses Chemaswet, an onion farmer in Mutyoru Zone A Village, Kapchorwa district says at an average of sh1,000 per kilogramme, this means a farmer can get a gross revenue of up to sh23m per acre a season.
High yielding varieties
Jambar F1 is the most popular variety among farmers with a potential yield of 23 tons per acre. The jambar F1 is a long-day onion variety maturing in 90 days from transplanting.
According to Chemaswet, it is suitable for warm climatic conditions. It has red bulbs, weighing about 200 grams on average with bulbs having a shelf life of up to six months under proper storage.
It does best around mountainous areas like Kapchorwa, Mbale, Kabale, Ntungamo, and Kasese.
The other varieties not very popular in Uganda include red pinoy, red cornet, Bombay red, red creole and texas grano.
Planting
Joseph Munerya from Kapchesombe parish in Kapchorwa district says a farmer should prepare the nursery bed on well-drained soils.
“It is advisable to use seedling trays to ensure that little or no seed is lost during this process. Commercial plant raises can help farmers raise healthy seedlings for use and make sure the soil is well fertilised,” he explains.
He says fertilised applications should be determined by soil analysis. Most onion roots are in a 15cm radius from the stem and are, therefore, shallow feeders.
“If the soil PH is less than six or the available calcium is less than 2300kg per hectare, apply and incorporate agricultural lime at the rate of 2500kg per hectare about 8-12 weeks prior to planting. Lime requires time to react with acid soil to raise the PH,” he explains.
Munerya adds that in soils low on phosphorous, apply and incorporate approximately 94kg of phosphate per hectare. Generally, it is suggested that the phosphate be banded 6-8.5cm below and on both sides of the rows where onions will be planted.
Nitrogen applications are critical in terms of quantity and timing of application. The amount of nitrogen supplied depends on the soil analysis. Poor soils may require up to 180kgs/hectare for direct sown crops.
Average soils would need lower levels -120-140kg/hectare.
Soils low in potassium require an application of 100kg/hectare before planting. The remaining potassium can be applied with the first nitrogen application at a rate of 85kg/hectare, (three weeks after transplanting or when the seedling has reached 3-leaf stage).
In applying pre-plant fertilisers, it is best to band 6 to 8cm below the seed to transplant, rather than broadcasting and incorporating.
Munyera says seedlings are usually ready 5 to 6 weeks after planting, when a majority of the seedling’s necks are pencil-size (65-80mm) in diameter, 10-15cm tall.
When irrigating, ensure systems are ready, so that irrigation can commence immediately after transplanting to prevent losses of the plant population. Planting space; 15-20cm between rows x8cm within rows
