How to grow sunflower for high yields

Sunflower is a viable commercial crop which was introduced in Uganda in 1920s. Most farmers engaged in growing it do it for commercial purposes and since then its production has increased. It is majorly grown in east and northern Uganda.

It is mainly grown by farmers in Lango and Acholi sub region, parts of Teso region, Mbale mainly in Sironko and Bunyoro in Masindi and Kiryandongo districts.
The breeding of sunflower varieties is done by the National Semi Arid Resources Research Institute (NaSARRI) and Dr Moses Biruma the programme leader for oil crops at the Institute gives excerpts about the agronomy of the crop.

Sunflower varieties
Dr Biruma explains that scientists have embarked on breeding highbred varieties which they are encouraging farmers to grow.
The most recently released are Sesun 1H which has features of uniform growth both at vegetative stage and after flowering. The head bends and forms a goose neck which is always hidden below the leaves thus avoiding flying birds.

It matures between 89-100 days and oil content is 43 per cent and the seed coat is black.
The other is Sesun 2H which is medium maturity. It is very vigorous in growth with large leaves. It grows uniformly and with big heads which tend to twist. It has the same maturity period with oil content of 36 per cent and it can yield up to 1,600 kilogrammes per acre.

There is the open pollinated variety namely sunfola with yield capability of 600 kilogrammes per acre.
These varieties are accessible at the research Institute but for farmers who are far arrangements can be made for delivery to their respective places.
The cost of the hybrid varieties is between Shs25, 000 to Shs40, 000 per kilogramme depending on availability.

Pests and diseases
Although a number of insects and diseases may attack sunflower, the effects are usually not serious enough to hamper yield.
Insects such as cutworms, dusty surface beetle and ground weevils may damage emerging seedlings and birds usually feed on the seed when the plants are mature.

The most serious diseases are caused by fungi and they include rust, downy mildew, Verticillium wilt, Sclerotinia stalk and head rot, phoma black stem, charcoal rot and leaf spot. They are common in virgin lands because they are soil bone diseases.
It is mainly common in land where beans and cotton has been grown because it causes rotting same to the plants.

Another common disease is Crinkle leaf which is viral disease affecting leaves of planting causing stunted growth.
Farmers are advised to prune out infected leaves; use adequate plant spacing to reduce humidity around plants and promote good air circulation; disease can be controlled by application of appropriate foliar fungicide and crop rotation by planting cereal crops as a means to get rid of soil bone diseases.

Harvesting
Start harvesting as soon as 80 per cent of the sunflower heads are ripe in order to minimise loss from birds and from shattering. Most sunflower plants take between 100-120 days to grow and it is important for farmers to observe this period.
Harvesting is done by cutting off the head when it is not completely dry, they are stored under the shed on polythene mat and the seed is processed by threshing using sticks.
The seed is then dried under hot sunshine for a period of one week. The harvested sunflower should not be left to dry completely because it becomes a challenge to separate the seeds.

Challenge of imported seed
Dr Biruma states that there is a challenge faced by farmers who are contracted by some oil producing companies because they tend to import highbred sunflower seed from South Africa. I kg of this seed is sold to farmers between Shs40,000- Shs60,000.
Once farmers have harvested sunflower, they sell the processed seed to these companies between Shs900 and Shs1,300 per kilogramme.

He is discouraging sunflower seed importations from other countries because some lack germination viability and some are infected by diseases.
For instance, farmers in Kiryandongo were given seed infected with disease and they had crop failure of 100 per cent and they ended up suing Mukwano group of companies.
He is encouraging these companies to import seed which can be grown and multiplied within the country by farmers themselves. To him importing seed is depriving farmers who are capable of multiplying seed to earn extra income.

Land preparation
When preparing soil for sunflower, farmers are advised to aim for efficient use of rainfall and soil moisture. The following indicators are cardinal;
• It is important to break the soil to its fine texture to ensure maximum rainfall infiltration and to provide a suitable seedbed.
• Clear the bush one month prior, allow it to rot and carryout the first and second ploughing but ensure the grass decomposes to provide manure to the soil.

• It is important to cultivate the crop in rotation with maize or sorghum to benefit from the dense mulch produced by these crops. Mulching protects the soil from the impact of raindrops, which seal the surface and reduce the Infiltration rate.
• Farmers are advised to plant at the onset of rainfall meaning land preparation has to be done before the rains start.
• Avoid planting sunflower in water logged swampy area, if a farmer prefers to do so, then proper drainage system has to be provided. The quantity of viable seed per acre is three kilogrammes.

Spacing
• The best spacing is 75cm by30cm apart, but wider spacing can be used although thee yield will be slightly low.
• Plant sunflower seeds at a relatively shallow depth of 25mm deep in soil with a high clay content and up to 50mm deep in sandy soil.
Farmers are advised to plant three seeds per hole.
• Farmers who used seed planter are at advantage because a good planter can space seeds uniformly and has a good depth-control mechanism. It should also be equipped with press wheels, as good contact between the seed and the soil is essential for germination.

Weed control
Young plants are highly sensitive to strong weed competition and cannot develop fast enough to form a full shade covering to suppress weed seedlings. For this reason, the first six weeks after planting are a critical period for the crop and farmers are expected to weed at this period.
It is advisable to weed the farm twice but for those who prefer to use herbicides it is advisable to spray the field seven days before planting is effected.
Yield can be increased significantly by keeping the land free of weeds during this time.