Baseline information on agricultural practices in the EU ... - Europabio

Nitrogen is essential for rapid expansion of leaves. It therefore needs to present at seedling
emergence. 70% of the crop‘s needs is taken up between the end of May and mid-July (ITB). By midseason
the canopy has been formed and nutrients should be deviated to the root. Excess late
nitrogen would still stimulate leaf growth and would have negative effects on root purity and sucrose
content and extraction.
As mineralisation of humus is limited early in the season, mineral nitrogen is applied before sowing
and/or at early plant stage to meet the crop’s needs. About 2/3 rd is provided by sources in the soil,
1/3 rd comes from the mineral complement (ITB).
Table 9: Average uptake of the most important nutrients by a sugar beet crop (IRS)
nutrient
uptake (kg/ha)
root crown + leaf total
nitrogen (N) 75 145 220
phosphate (P2O5) 42 40 82
potassium (K2O) 130 285 415
sodium (Na2O) 12 130 142
magnesium (MgO) 25 40 65
The amount of nitrogen fertiliser further depends on the type of the previous green manure crop, if
any, whether livestock manure has been applied, and whether grass has been ploughed under (IRS).
Often used green manure crops preceding sugar beets are white mustard (Sinapis alba), oil radish
(Raphanus sativus subsp. oleiferus) and grass.
Mineral fertiliser is applied 1-2 times; on sandy soils also manure is applied in spring (NL). On clay
soils nitrogen is given already in February (IRS, ITB), sometimes only partly with the rest at the 2-6
leaf stage. It is also possible to apply the total amount at the 2-leaf stage. Local application in the row
is also practiced to lower doses and to spare the environment (ITB). On sandy soils the necessary
minerals are applied shortly before sowing.
Depending on whether the amount of phosphorus stored in the soil is sufficient or not, application is
done in autumn or spring time (to keep level), or in spring respectively. On clay soils potassium is
provided preferably in autumn, on light soils spring time is the optimum period.
Sodium sometimes has a positive effect on root mass and sugar content, especially on sandy soils
(IRS). Light soils also are sensitive for magnesium deficiency. On clay soils magnesium is sprayed
when deficiency symptoms become visible.
Boron deficiency causes heart rot. Again sandy soils are most vulnerable. A field with a history of
boron deficiency should receive e.g. borax before sowing. Alternatively leaf fertilisers are sprayed
between the 2-leaf stage and crop closure.
Farmers usually base their calculations for the optimum fertilisation on soil analyses from samples
taken in winter. Several <strong>information</strong> services provide models and advice to calculate the right dose of
fertilisers to apply in the fields as this may differ from one field to another. Examples are: Fert-Consult
(Belgium); Fertibet and Azofert (France); LIZ-Dungpro and BISZ Düngung (Germany); Integrated Beet
Nutrition - N.I.B. (Italy); Betakwik N-P-K (the Netherlands) (CIBE-CEFS, 2010).
The general practice to prepare the soil is ploughing in order to incorporate crop residuals and weeds
in the soil. On heavy soils this is done in autumn with the advantage that frost can break clods (Table
10). On sandy soils ploughing and seedbed preparation is often done in one operation or the soil is
tilled shortly before preparing the actual seed bed. Local legislation might restrict soil preparations to
prevent erosion. For the seedbed the soil needs to be moist and have a fine structure in the top 3 cm
layer.
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