Speeding up sunflower establishment to boost yield

Publish on 15 June 2024

Expertise, Solutions, Sunflower

The establishment of sunflowers is a key step for ensuring an optimal plant population. Even if larger heads can be observed in low plant populations, this is insufficient compensation. An emergence density of less than 50,000 plants/ha associated with an irregular stand strongly deteriorates the yield and the oil content. It is therefore essential to provide as much protection as possible from pest-related losses. Soil, climate, equipment, genetics, biostimulants: the strategy consists of creating optimal conditions by bringing into play all the available drivers. Vigor Plus and Fortify solutions for sunflower crops are real assets to secure yield.

To limit damage caused by birds and soil pests sunflowers need to emerge quickly and evenly. The quality of establishment is therefore critical when aiming for high yields. Optimal sowing conditions include the following:

Soil that is drained, well-prepared (on the surface and in depth) and warm enough (above 8°C at a depth of 5 cm).
An early sowing date: analysis carried out by the French institute Terres Inovia, between 1996 and 2019 highlighted a statistically significant yield gain for plants sown in the first half of April.
A well-calibrated seed drill: the recommended sowing depth is 2-3 cm in cool soil and 4-5 cm if the soil is dry on the surface. With a conventional single-seed drill, the sowing speed must be limited to 5-6 km/hour to ensure consistent positioning of the seed.
Sufficient seed density adapted to each situation: this factor varies according to the water stress of the plot, spacing between rows and the sector. The density calculation tool proposed by Terres Inovia makes it possible to estimate the optimal density.

Quick and even emergence with Vigor Plus genetics

Once these conditions have been met, the farmer may also adjust their varietal choice to further secure the establishment of their crop. Indeed, the varieties in the Vigor Plus range are differentiated thanks to the following criteria: speed of establishment, even emergence and rapid coverage between the rows. “To receive the Vigor Plus label, a sunflower variety is tested over three campaigns, using different seed batches, under very diverse pedoclimatic conditions. This allows us to validate that these are intrinsic varietal characteristics” explains Manon Libert, sunflower product expert. Thanks to these rapid establishment criteria, exposure time to pests is reduced, light interception increases and plant growth is more regular. Outcomes: a significantly higher than average starting strength, a more even stand and an average yield gain of around 5% (averages from six years of farm trials).

Vigour and homogeneity

Control

Fortify sunflower, the benefits of bacteria to support genetics

For several years, RAGT has been developing the Fortify solution which is applied to seeds of different species. This solution includes biostimulants that vary from one species to another, selected after numerous field trials, over several campaigns, on different varieties.

In sunflowers, Fortify is composed of two strains of bacteria naturally present in the soil (Bacillus Mucilaginosus and Ochrobactum sp.). In particular, these bacteria help to solubilise phosphorus and stimulate the production of auxins to accelerate root development. The Fortify sunflower solution helps improve emergence and brings a 3% yield gain on average over five years.