Sunflower shows a wide adaptability to almost all soil types, from very poor to very fertile. It also adapts well to both sandy and loamy soils. Its root system penetrates deep into the soil, so it prefers well-ventilated soils that drain easily. In terms of soil chemistry, it prefers soils with pH 5.5-8 and shows problems in soils with high salinity.

Nitrogen is the main nutrient as it contributes to good plant growth, good yields and increased oil and protein content. Applying too much nitrogen degrades protein quality, while increases the risk of disease and sloping. The total nitrogen requirements of sunflower are in the range of 12-16 kg per stremma. 70-80% of the nitrogen is applied in ammoniacal and urate form in the basal fertilization just before sowing and is incorporated into the soil. The remaining is applied during surface fertilization in ammoniacal, urate and nitrate form.

Phosphorus affects the yield and oil content of the seed. It is applied during the basal fertilization, depending on the previous phosphate fertilization in doses of 4-7 kg per stremma. Potassium contributes to the increase in oil content, while its deficiency causes an increase in the percentage of unsaturated acids. It is applied during the basal fertilization in doses ranging from 8-12 kg per stremma.

A fairly common nutrient deficiency in sunflower crop is that of zinc. Zinc can be added in mineral form to the soil or at a later stage though foliar spraying. Also, significant problems in crop can arise from boron deficiency, especially in calcareous or sandy soils, but also in soils where sunflower has been monocultivated for many years without the addition of boron. Boron is applied preventively with the basal fertilization in the soil or later foliar when the crop is at the 10 true leaf stage.

Our Suggestions

Basic fertilisation

Fertilizer type	Dosology
36-16-0	20-25
31-8-13	20-25
30-8-12	20-25
25-15-0	25-30
20-10-0	25-30
25-5-5+0,5Β	25-30

Surface fertilisation

Fertilizer type	Dosology
46-0-0	5-15
46-0-0	10-20
34,4-0-0	15-25
33-0-0+31SO3	15-25
27-0-0	20-30
21-0-0	30-40