Soils & Drainage Services

GPS Sampling

Which Method - Grid or Zone?

SAC Consulting provides pH sampling on a grid based system using a GPS Technology which provides clients with a cost-effective, accurate and repeatable service to ensure efficient use of inputs (lime, P & K).

Analysis costs are kept to a minimum by sampling phosphate and potash in zones areas based on the farmer's knowledge. This method provides accurate results from which future applications can be calculated.

Using a quad bike and GPS equipment to record the sample locations, twelve cores of soil are taken from every quarter hectaire grid to make up the sample. With only a small amount of soil required for the pH analysis, the remaining sample of soil - which is representative of the whoe field (or zone) - ensures that any subsequent analysis (e.g. P & K) is accurate.

The processing and mapping of results is included in the sampling price and is provided both electronically and in hard copy. All lime application maps are created on demand and emailed to you or your chosen limespreading contractor in a suitable format.

Grid Sampling for pH - Whis is pH so undpredictable?

  • Traditional one rate per field lime spreading techniques make it difficult to know where highs/lows may be and can lead to greater pH variation across the field
  • Amalgamation of several fields into one results in varied soil types
  • Different cropping history/land management
  • Light and heavy soil types within field
  • Yield differences

After many years of experience, SAC Consultiung has found the optimum sample size to be 4 per hectaire. This methodology picks up the pH variability within the field and the farmer can then apply only the required amount of lime necessary to bring that quarter-hectare grid up to the required target pH.

Zone Sampling for Routine Analysis (P & K etc)

Routine analysis (included P, K, Ca, Na, Mg, pH) and all other tests can be taken from the remaining soil left over from the pH sampling. Using the client's knowledge field zones can be determined, creating additional maps which are then used to correct levels of phosphate and potash using Variable Rate Applications maps or simply done by eye using a skilled operator.

Contact your local SAC Consulting area office for more information about this service and a summary of pricing.

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