Stay sharp when planting sunny sunflowers

October 2015

In the past year, when many of the regions of this country were severely affected by drought, the value of sunflower as a drought resistant crop became evident.

Where maize plants in some areas like here in the North West province yielded between 200 kg - 1 ton which translates to R500,00/ha - R2 500,00/ha, many sunflower fields still delivered surprising yields from between 0,5 ton/ha - 1,2 ton/ha or R2 500/ha - R6 000/ha. This is very significant and can mean the difference between surviving a bad year and possible bankruptcy.

Sunflowers sucker down deep

The danger we have to be aware of however is that the reason why sunflowers can do better in a drier season is because they have a deep, highly efficient root system which is capable of drawing moisture and nutrients from deep in the soil.

This means that planting maize after a sunflower crop has been planted in a field is very risky, especially after a dry season, and wise decision making is required. Also there is a big red light warning against planting sunflowers on lands where sunflowers were grown during the past season. If possible rather plant your sunflowers on lands which were planted to maize in the previous season or even better, plant sunflowers into lands which were fallowed
if at all possible.

Sunflower stand must not be sparse

Do not be tempted to plant a lower plant population with sunflowers as we sometimes do with maize when drier conditions are anticipated for the season ahead. The biggest reason why good yields are not achieved in sunflowers is poor stand. Try never to have a stand of less than 24 000 plants/ha. Ideally 30 000 plants/ha with a good fertilisation program, good weed control and good rains should be able to return the 2 ton/ha crop we all aspire to. If your plant population is low you will struggle to achieve 1,5 ton/ha and your profitability will be threatened.

Sunflowers struggle against weeds and surface crust

Another vital key to achieving a good sunflower yield is good weed control especially in the early weeks while sunflowers are germinating. Try and avoid mechanical cultivation except for a scarifying “duisendpoot” operation just before emergence. Three to four days after planting it is essential to run a duisendpoot over your newly planted crop because a hard crust is also a big culprit for causing a poor stand – and stand (plant population) is everything!

Sunflowers seeds stuck in the mud

Another factor which affects sunflower stand is poor germination due to excessive heat at the time of planting. Because we sometimes have to plant our sunflowers in January or even into early February, temperatures by this time are often reaching up to 32°C - 35°C, but these temperatures are not really ideal for sunflower seed germination. Sometimes the seeds will germinate but the high temperatures may cause them to wither and die. Another risk factor is that the top soil tends to dry out fast in the heat and therefore a farmer is forced to plant the seeds a bit deeper where the soil is wetter. This can be a solution but it is also a risky practise as one hard shower of rain after planting will cause a thick crust to form and the seedlings will be unlikely to emerge. It is important for a farmer to be aware of these risks. At times it is even better to replant the field rather than sit with a sparsely populated one which will never produce a profit.

Sunflowers can be a most rewarding crop and markets are reliable but it is important to choose their planting time carefully and make sure of a good plant population. A good sunflower grower will nurse his fields in the first few weeks as this is the most critical time to guarantee success.

Article submitted by Jenny Mathews, Pula Imvula contributor.
For more information, send an email to jenjonmat@gmail.com

Publication: October 2015

Section: Pula/Imvula