Soil sampling and analysis
The reliability of analytical results and recommendations depends, ultimately on the sampling accuracy. The 3 stages in sampling are key, taking a representative sample, correct packing and immediate despatch to lab and supplying all the necessary background information.
A representative sampling path is required across the field. The W-pattern is adaptable to most shaped fields.
Soil analysis is an essential tool for the prediction of available nutrient levels for optimum plant growth and crop production. The available levels of the following nutrients can be accurately analysed Phosphorus, Potassium, Magnesium, pH, Calcium, Sulphur, Sodium, Iron, Manganese, Copper, Zinc, Boron, Molybdenum (Cobalt, Iodine for Grassland) and it is recommended that a testing regime of this type is carried out once every 4 years. As a general rule, fields up to 10 Ha (25 Acres) in area can be sampled as one unit, providing each field is uniform e.g. with regard to soil type, past cropping, lime and fertiliser usage. Fields created by hedge removal are unlikely to be uniform. Large fields, and fields which are not uniform, should be subdivided and each part sampled separately. Use a clean auger, hand trowel or spade (preferably chromium plated or of stainless steel). Carry a plastic bucket.
Start away from the gate and avoid all areas which are not representative of the field as a whole such as headlands, hedges, ditches, footpaths, fences, fertilizer, lime or manure dumps. We recommend at least 20 samples, taken at regular intervals along the sampling path. Do not reduce on this number. 20 samples are required even from small fields or areas.
At each of the 20 sites, remove the top 5 cm (2") of soil and discard. Take a sample to a depth of 15 cm (6") for arable crops and place in a bucket. Thoroughly mix all your samples avoiding spillage. Fill your sample bag and seal securely. Label.