FERTILISATION OF PREMIUM WHEAT
- Yield target at high quality - 700 kg/dca
- Total nitrogen required for the vegetation of premium wheat at this yield - 23 kg/ha active N
- Precursor - sunflower - do not rely on residues!
- Rapeseed precursor - can rely on approx. 4-5 kg/dca N
Autumn fertilisation:
- In a normal autumn, 1000 tillers per square metre (350 plants with 3 tillers each) take up about 2-3 kg/ha of nitrogen - presumably this is the amount you supplied pre-sowing.
- With the long growing season the plants have had this winter, I consider all the absorbable soil reserves to be depleted, so we would not expect any extra nitrogen to be available from mineralisation.
- Mineral fertilizers are washed out by rapid melting, lots of rain, etc., so take stock of when you fertilized, what conditions were like during and after fertilizing. Estimated mineral fertilizer losses from early winter fertilization, regardless of nitrogen formulation, are as high as 50%. Normally about 20% is lost. In this sense, the following general example can be given:
-> Spring feeding I recommend as a guideline 20 kg/dca N after sunflower, 18 kg/dca after maize and 16 kg/dca after rape, divided into 3-4 doses and monitoring of rainfall:
- the first dose of N applied is about 30% of the fertiliser rate.
- second dose at stem growth stage, early-mid April:
a/ with good moisture - the dose is 50% of the total rate
b/ in case of drought - reduce to 30%
- per flag leaf approx. 10 or 20% - 2-4kg/dca N in amide form or liquid-organic nitrogen. This rate can be divided into 2: per flag leaf and per stem.
- Per stem, if there is moisture in the crop, a further 2 kg/dca (10%) can be given in amide form (nitrate is only used in early spring).
- Required micronutrient - 5 g/dca Boron at stem growth to flag leaf
- Do NOT apply Manganese late in spring unless there has been sufficient autumn tillering, but it should be early and completed when growth starts
- Sulphur mandatory in spring 3-4 kg/dca (autumn application is generally pointless). I recommend Kieserite - magnesium sulphate or similar compounds. Sulphur can also be applied as part of sulphur-containing nitrogen fertilisers, but then magnesium must be provided at least as a foliar fertiliser.
- Magnesium is severely underestimated in Bulgaria and plants need significant amounts - cereals extract about 2- 3 kg/dca!
- Copper - always has a positive effect on yield, I would accept it as a standard for wheat; in premium wheats it is an absolute must, especially on humus soils. It is best fed to a flag leaf - boot stage.
- Molybdenum - important for protein formation, recommended in small doses around emergence to prevent molybdenum deficiency in the formation of grain quality.
- Potassium - if potassium has not been stocked in the rotation, potassium can also be applied in early spring as a granulate in the crop or as a liquid foliar fertiliser
- Phosphorus - for high yields in cereals, phosphorus fertilisation within the rotation is a must ! A plan can be made by field and year categories. A spring application to the wheat crop would not have a full effect, and there is also the danger of a negative reaction with some plant protection products !
- Of the plant protection products, avoid strobilurins or use only in early spring and never after weeding! In more advanced phases, it is better to use azoles.
- Growth regulator in Bulgaria better be avoided due to the onset of dry spells, and here the types of active substances are limited, apply only in extremely wet spring.
Fertiliser rates are always the result of soil type, climatic conditions, type of fertiliser, precursors and generally the stocking and rotation cycle, so the examples given here are only indicative, they do not claim accuracy and universality of application.
It is up to each individual to analyse his own soil, activity and current condition and, in accordance with general patterns, make a specific fertiliser plan. Keep in mind that it is important to tailor your decision not only in relation to the current field condition, but also a 3-4 week rainfall forecast, as what you do to your fields now will have an overall impact on the plants in a few weeks.
Ing. Evelina Marinova
March 2018
