By Joubert Swanepoel and Lardus Basson – sponsored content

Approximately 550 000 to 600 000 hectares of sunflower are planted annually in South Africa’s summer sowing areas. The largest part of the crop is normally planted in January. But is that the ideal time, and can earlier planting have more benefits for farmers?

What do farmers who plant early say?

A few sunflower farmers tell us about their experiences with early plantings.

Ferdi du Plessis from the farm Kalkfontein in the Lichtenburg district of North West says sunflower is an underestimated arable crop because it is low-risk and requires fairly low input costs. He tries to plant early because the crop benefits from a longer growing season, which considerably improves the chances of a higher yield. According to Ferdi, early sunflower plantings in a normal season can improve yields by up to 500 kg/ha compared to late plantings. He says the ideal planting date for early sunflower in the Lichtenburg district is usually from mid to late October, rainfall permitting.

In terms of cultivar selection for his early plantings, Ferdi prefers Agricol’s flagship conventional cultivar, Agsun 5270. However, he says Clearfield®Plus cultivars also integrate well because they make management easier and reduce labour costs.

Manie van Biljon from Braunschweig farm in the Senekal area in the Free State likes to plant sunflower as early as possible. He says it spreads the workload on the farm and creates an income at a time when cash flow is under pressure. Manie tries to plant early sunflower from the last week in August so his crop has finished blooming before the midsummer drought.

In terms of yields, he says early sunflower plantings normally do better than later plantings, but this depends on rainfall, which can be erratic in many areas.

He likes to plant Agsun 5103CLP. He says Clearfield®Plus cultivars also work well for early plantings because the sunflower is quite advanced when most weeds start to germinate, meaning they can be controlled easily.

Gabriël Richter from the farm Toevlug near Bothaville in the Free State says he plants sunflower early because the crop has a lower input cost. The biggest benefits of early planting are early cash flow, workload distribution and peace of mind. Gabriël says planting early means the autumn rains can be used more optimally to store soil moisture for the following season. With fields harvested earlier, liming and soil correction can also be done earlier in winter. Gabriël reckons early October is a good planting time for sunflower. He recommends Clearfield®Plus cultivars, saying they lower the farmer’s spray risk in relation to the waiting period for follow-up crops. He prefers the cultivars Agsun 5108CLP and Agsun 5109CLP.

What does the agronomist say?

Sunflower is known as a cool weather crop that can germinate at soil temperatures as low as 4 °C. The soil temperature in which sunflower can grow with great success is 10 °C-31 °C. Thanks to the crop’s good frost tolerance, it can be planted earlier and later than other summer crops. In terms of growing temperature, sunflower can withstand extremes. It is known for being moderately frost-resistant in the seedling stage and can survive temperatures as low as -2 °C.

Sunflower’s emergence and realised plant stand are also usually better when planted early, as the soil is cooler than later in the season.

One of the biggest reasons to plant sunflower early is that the crop normally has a higher yield potential. Early planting allows sunflower to take full advantage of the growing season and heat units, improving development time. This can lead to healthier and stronger plants with higher yield potential due to longer periods of photosynthesis – something that’s essential for plant development and seed production.

In areas where water availability can be a limiting factor, especially during a midsummer drought, early planting dates can help sunflower to make better use of available soil moisture, and root systems can establish better. Since sunflowers have a taproot system, they can access deeper soil moisture reserves. This can reduce the risk of drought stress during important growth stages. Early sunflower is therefore better equipped to withstand dry conditions, which can lead to more stable yields.

Early sunflower can also help farmers with better crop rotation planning, as the growing season is over before autumn. Farmers can therefore make optimal use of the autumn rains and start accumulating soil moisture earlier for the next season. Land preparation can also take place more quickly, which can lead to efficient use of the farmer’s resources.

When sunflower is harvested early, it can also contribute to better soil health, because farmers have time to plant winter cover crops on those fields. This can improve soil sustainability.

What does the agricultural economist say?

Over the past 10 years, market trends indicate that sunflower’s Safex prices are normally much better earlier in the season (March) than later (April and May). There is therefore an opportunity for farmers to achieve higher profit margins by supplying and selling sunflower earlier in the season.

The budget in table 1 shows that sunflower supplies and sales can lead to almost R400/ha more profit simply on the basis of the price difference between early and late supply, based on a 1,5 t/ha grain yield for the early and late sunflower plantings.

When taking into account that early sunflower can normally realise higher yields than later plantings, a second scenario could be possible (see table 2). Here you can clearly see that possible higher sunflower yields, with a higher price for early supply, can be much more rewarding for a farmer.

Cultivar choice

Cultivar choice plays a big role in the successful cultivation of any crop and sunflower is no exception. Package plantings of two or more cultivars can effectively spread farmers’ risk of diseases and possible climate changes. A cultivar package should preferably meets the farmer’s yield and long-term stability requirements. Cultivars in the package should complement each other with regard to their flowering date and the length of their growing season.

As the South African climate can create difficult production conditions, it is advisable to select cultivars that have been developed locally. These cultivars are more adapted to local climatic conditions, especially for when plantings are subjected to sudden stress conditions. Locally developed cultivars are also more heat tolerant, while imported cultivars can be more sensitive to heat and therefore pose a higher risk to farmers.

Agricol’s Agsun sunflower range is known for its stable yield in different climate conditions and on different planting dates and is proudly locally developed and produced.

Joubert Swanepoel is the chief agriculturalist at Agricol and Lardus Basson is an agricultural economist at GWK.

ENQUIRIES: agricol.co.za