Soil Sampling should be carried out a minimum of every 4 years on combinable arable farms or for more specialist crops with specific requirements before each crop is crown.

Field Advisers at Needham Chalks (HAM) are able to carry out all types of soil sampling from pH to P, K, Mg and also full trace elements as well as GPS Nutrient mapping.


pH soil sampling is conducted by taking soil samples methodically across the field every 1-2 acres and conducting on the spot samples. This is done by placing a few grams of soil in a test tube and mixing it with barium sulphate, de-ionised water and indicator and shaken. The barium sulphate ensures flocculation and precipitation of colloidal clay. The resulting coloured solution is compared with a colour chart to give the correct pH reading.

Test results are plotted on a field map so that any lime required can be applied in the right place and at the correct rate. Soil indicator solution is the only reliable method of measuring the soil pH however, poor and patchy crops and the presence of some acid preferring weed species can be used as a rough indicator. We pride ourselves on running Trimble GPS systems to enable us to apply lime variably. This enables an accurate and consistent mapping service for the customer.

Soil sampling test tubes.


Needham Chalks developed their GPS liming service in conjunction with Morley Farms near Wymondham, a commercial farming enterprise that hosts field trials and research as part of its role within The Morley Agricultural Foundation.

The system involves taking pH samples at half-hectare intervals, which are then mapped electronically to create a digital application map which can be transferred to the machinery spreading lime.

Our satellite-guided liming system is helping farming efficiencies since lime will only be spread in the areas where it is required.

Similar precision systems are increasingly being used to apply pesticides and fertilisers as the industry strives to become more cost-efficient and reduce the impact of agricultural chemicals on the land and water courses.

Example GPS precision pH sampling map.

For more information about Soil Sampling please contact us.

Variable Rate PK & Mg, pH Sampling and GPS Precision Sampling available upon request. Please contact us to discuss your requirements and obtain a quotation.