Senioradviser Leif Knudsen, DAAS

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The normative basis and how it is developed

• by
• Senioradviser Leif Knudsen, DAAS

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Task for fertiliser plans
For the farmer To have a operational plan for
use of manure and Fertilizer on field level, who
gives the optimal and Legal type, amounts and
recommende application Dates.
For the authorities To be able to control that
the farmers use of mineral Fertilizer and manure
and e.g. croprotation is due to Good Agricultural
Practice.
If the norms/standards in the legislation is
based on Optimal economic fertilizing, the
principles and norms Can be common for
N-regulation and practical fertilizer planning
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Calculation in fertilizer planning
Nor mati ve 1
Nor mati ve 2
Nor mati ve 3
Nor mati ve 4
Model
Output
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The need for different normative

• Norms related to crop
• Nitrogen demands
• Yield corrections for nitrogen
• Standard yields for main crop (grain) and straw
• Concentration of N, P, K, Mg, S, (Cu, Zn, B)
• P, K, Mg, S, (Cu,Zn,B) demand at standard yield
• Norms for manures
• Amount per animal unit
• Dry matter
• Content of Total-N, amm. N, P, K, Mg, S,
  (Cu,Zn,B)
• Norms for mineral fertilizers
• Concentration of N,P,K,Mg,S, (Cu, Zn,B)
• Norms for parameterization of models

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Principle for norms for crops according to
nitrogen regulation
Normative for crop
Rules for corrections
Normative for manures and demands for minimum
utilizations
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Normative For crops From the fertilizer systems
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Calculating the N-demands standards

• The basic must be trials
• Transformation of standards from big crops to
  smaller crops from type, yield level, balances
• Best with local trials or from comparable
  climate
• Recommendation of at least 10 trials in 3 years
  on defined conditions
• The standards must be revised according to
  increasing of yields during time

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Correction for conditions in trials setting
correction factors

• Results from the field trials are collected in a
  database and organised in groups according to
• Soil type
• Previous crop and the crop before the previous
  crop
• Supply of animal manure
• Geography
• Year
• For each of the groups a standard demand for
  nitrogen is

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Scientific N-demand Depends of
N-quotas are corrected for

• Previous crop
• Organic manure last year
• Cropping history in a long period
• Soil type
• Yield level
• Soil tillage
• Price on protein
• N and crop price (relation
• Experience from fied
• N-min- in soil in spring
• Total-N in spring

• Previous crop
• Soil type
• Long term effect of org. manure
• N-prognosis each year

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Modelcalculated standards in spring
barley Compared with optimum in trials
250
200
150
calculated norm,kg N/ha
100
50
0
0
50
100
150
200
250
Optimal N-rate in trials, kg N/ha
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Correction For deviation in yields from norms
N-demand Nnorm(expected yield standard
yield) x corr.factor Winterwheat Nnorm 115 kg
N/ha, Standard yield 4 ton expected yield 7
ton/ha N-demand 115(7-4) x 24,7 189
kg
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Yield level in calculation of qouta

• The farmers are always very optimistic in
  setting expected yield (in general and specially
  when he knows the correlation between yield and
  qouta
• In a fixed quota system standards must be given
  for yields depending on soil types
• The might be a need for a definition of eg. 3
  soil types with different standards for yield and
  corresponding N-quota
• From the formulas in the fertilzerplan system
  you are able to make such a calculation

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Outlines of danish standards for optimal N-rates
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Table 9 Correction of nitrogen demand according
to after-effect of previous crop, kg N pr. ha.
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Table 5 Correction factors for different soil
texture classes.
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Table 6 Correction factors for different
contents of humus.
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In fact the N-demand is even more dependent by
cropping history
Table 1 Correction for long term cropping
history, danish
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Table 10 Mineralisation constants for different
types of green manure. Percent of total supplied.
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Problems with model according to legislation
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Proposals

• Make a leaflet.. Which present the rules, norms
  and sheets where it is possible manual to
  calculate the allowed Nitrogen Quota In mineral
  fertilizer
• Norms for nitrogen should be given for 3 soil
  types with corresponding yield and N-quotas
• Design the computer system to handle it
• Extract some key figures in the plan, which can
  be controlled.

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Proposals - continued

• Make a board that sets the nitrogen standards for
  the crops and manure standards

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For farming in respect of the aquatic
environment...