Nutrition check list
Good crop nutrition will help to achieve maximum crop productivity for maximum profits with minimal impact on the environment while adhering to all legislation. Some basics principles should be followed to achieve these goals:
Identify the soil type in order to understand nutrient requirements.
Analyse soil for nutrient content every 3-5 years and adapt nutrient inputs to maintain values of:
pH 6.5 (5.8 peat soils) P Index 2 K Index 2- Mg Index 2
Determine the Soil Nitrogen Supply (SNS) either by field assessment method or by sampling and analysis for soil mineral nitrogen.
Determine nutrient supply from organic sources and deduct available nutrient sources from total crop requirement.
Apply Phosphorus and Potassium to maintain nutrients from crop removal and apply additional quantities if soil indices are low.
Apply nutrients at the correct timing to match plant demand.
Check that the fertiliser spreader or sprayer is calibrated to deliver nutrient accurately.
Record all fertilisers and organic materials used.
N max limit
For full details of N Max limits please refer to the DEFRA document; Guidance on complying with the rules for Nitrate Vulnerable Zones in England for 2013 to 2016.
The table below highlights different N Max limits depending on expected crop yield and soil type.
|N Max limits*|
|Crop||Expected yield||Non-shallow soils||Shallow soil type (not over sandstone)|
1* An additional 40kg N/ha is allowed for milling wheat varieties.
2* An additional 80kg N/Ha is permitted to all crops grown in fields where the previous or current crop received an application of straw for mulching or paper sludge.
Wheat, autumn and early winter sown - Nitrogen
|Light sand soils||160||130||100||70||40||0-40||0-40|
|Deep clay soils||250||220||190||160||120||60||0-40|
|Deep silty soils||220||190||160||130||100||40||0-40|
Wheat, spring sown - Nitrogen
|Light sand soils||160||130||11||70||40||0-40||0|
|All other mineral soils||210||180||150||120||70||40||0-40|
Crop nutrient removal
Significant nutrients are removed from the field during crop removal. The levels of these nutrients that are removed from the system will vary significantly depending on yield and whether the straw is removed or incorporated back into the field. In order to maintain soil nutrient levels the nutrients that are removed with the crop need to be replaced by either fertiliser applications and/or organic additions.
The table below indicates the level of nutrients required to maintain soil indices at target Index 2 across a range of yield levels:
|Nutrient requirements (kg/ha)|
|Crop||Straw management||Yield (t/ha)||P2O5||K2O||MgO|
|Winter Wheat||Straw ploughed-in/incorporated||8||60||45||16|
|Spring Wheat||Straw ploughed-in/incorporated||6||45||35||16.2|
Sulphur: RB209 - Where sulphur is deficient then 25-40kg SO3 should be applied early spring before stem extension.
Magnesium: RB209 - At Mg Index 0, magnesium should be applied every 3-4 years at 50-100kg MgO/Ha