TRD: Institute for Plant Production: Laboratory Services: SOIL, WATER AND PLANT TISSUE LAB
Frequently asked questions
1. How often should I test my soil?
Every three years is recommended, unless a problem arises with plants that might be soil-related.
2. What are common mistakes made when taking and preparing samples?
The result of any analytical evaluation can be no better than the sample on which it is performed. The aim of sampling is to collect a portion of material that is small enough in volume to be transported conveniently and handle easily in the laboratory, while still accurately representing the material being sampled.
Avoid contaminating samples through contact with fertiliser or used fertiliser bags and the use of inadequate sampling equipment. (Read more about sampling procedures here.)
3. What test package do you recommend?
The standard analytical package forms the basis for all these recommendations. Trace elements and sulphur should be included when new land is opened up or the status of a land is unknown to the customer, or when it is known that trace elements have not been applied for a few years. It is particularly important to know the sulphur status in sandy and high pH or alkaline soils.
4. What are the analysis costs?
Please contact the laboratory for the costs involved.
Contact details: E-mail: Rudie van Zyl; or Telephone 021 - 808 5286
5. What is your normal turnaround time?
Depending on the current workload, the laboratory strives to deliver results within 5 working days after submission, with another week added should recommendations be requested.
6. What should the sample size be?
For leaf samples, the total sample should consist of at least 40 petioles and/or leaves. For soil, approximately two to three cups of the soil combined. (Read more about sampling procedures here.)
7. To what depth should the sample be taken?
Obtain soil from the surface through the primary rooting zone of the crop. The rooting depth will vary with crop type. For most plants, the top 0 - 20 cm is appropriate. For established grasses, sample the top 0 - 10 cm.
For vines and fruit, it is necessary to sample topsoil (0 - 30 cm) and subsoil (30 - 60 cm) separately.
8. What do you charge for fertiliser recommendations?
Fertiliser recommendations are done free of charge.
9. How many samples should I take per hectare?
It is advisable to sample 5 samples per hectare, one at each corner and one in the centre. If there are no obvious differences (texture, slope, drainage, colour, and past pest and fertility management), these samples can be pooled together and one representative sample submitted.
10. Can you check for diseases?
Contact our plant pathology laboratory.
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