Post harvest provides a good opportunity to carry out soil analysis for planned winter or spring cropping. Determining the soil nutrient status for phosphorous and potash by soil testing means nutrient application can be carefully targeted to meet crop requirements whilst eliminating the cost of unnecessary applications.

Regular soil analysis

Regular soil analysis (every four years) is required under phosphate regulations to show there is a crop requirement to apply chemical phosphorous.  Any chemical phosphorus applications must take into consideration crop requirement, soil fertility status and phosphorus supplied through organic manures.  For sampling one sample per field made up of 25 sub-samples is sufficient for fields up to 4ha in size.  Larger fields should be sampled every 4ha.  A field which has had areas cropped or fertilised differently need to be sampled separately and treated as different fields.    
Soil analysis results together with previous cropping history fed into the CAFRE Crop Nutrient Recommendation Calculator can be used to calculate crop nutrient requirements whilst keeping within Nitrate and Phosphate regulations.  

Crop Nutrient Recommendation Calculator

Soil analysis will also give pH results to indicate if liming is necessary to redress a low PH.  Once soil pH is known the agricultural lime association’s Lime Calculator is a useful tool for working out lime requirements based on the type of liming material to be applied.  The tool accounts for the differing neutralising values of various products allowing you to compare the actual cost per hectare to achieve a target soil pH of 6.5 for continuous arable rotations.  For further information on soil analysis and when best to apply lime in the rotation contact your local Crops development advisor.  

Lime Calculator
Crops Development Advisor

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