Soils & Growing Media

The analyses of soils and growth media are becoming more important in view of the fact that input costs are rising continuously, therefore necessitating the optimum utilization of all agricultural resources. The soil laboratory at NviroTek Laboratories has been especially designed to accommodate the requirements for throughput in the precision soil market. 2000 samples can be processed for standard analyses purposes within 24 hours. The equipment and process layout was only finalized after an intensive benchmarking exercise against six larger soil laboratories in North America.

Traditional extraction methods are followed, but alternatives, e.g. Mehlich-3 and DTPA for micro-elements are on offer. In addition to the standard analyses, other tests including texture, Boron Sulphur, Nitrogen and Carbon are available. At receipt, samples are dried and sieved; thereafter the sample density is determined before other analyses are done.

Thereafter, the density and other nutrients are analyzed. Please make sure that the correct extraction method, as used by the advisor for fertilization advice, is communicated to the laboratory. Excess samples are retained for 2 months in the original package for later reference.

The laboratory does supply plastic sample bags and 250 to 350 grams of sample is sufficient for the basic analyses.

You are welcome to use the attached sample submission form. (sample attached)

General Guidelines For Soil Sampling:

It is important that the sample accurately represents the fields to be fertilized. It is advisable that a separate sample is taken from each management zone or soil area .If the soil type and the management zone is similar, a composite sample of a field of approximately 20 hectares can be taken. Soil areas that differ significantly in appearance (color, slope, texture and drainage) within a field should be sampled separately. A soil probe is the best tool for obtaining a soil sample. If a soil probe is not available, a small shovel or a spade can work satisfactorily.

Follow a random pattern when sampling the area, avoid unusual spots and ensure that it is a truly representative sample. Approximately 10 to 15 individual cores of uniform size and depth, collected from throughout the sampling zone, should be composited in a clean, dry plastic bucket. Cores should be taken from the surface to a depth of 24 to 30 cm. Mix all the cores thoroughly and take a sub-sample for the laboratory. The laboratory sample should be approximately 300 grams/250 ml.

NviroTek Laboratories will supply small plastic sample bags on request. Please phone Leoni Erasmus on 082 889 0139 to make arrangements.

Mark the sample clearly and record relevant data on the sample submission sheet (sample attached). Avoid using a felt pen ,it smudges .Use stickers or staple a piece of paper onto the bottom of the sample bag.

Dispatch to the laboratory for analyses.

Soil Analyses:

Standard 1:
pH(water/KCI), P(Bray 1), Cations(Ca, Mg, K, Na), Exchangeable acidity, Density, %Ca, %Mg, %K, %Na, Ca:Mg, Mg:K, (Ca+Mg)/K, Calculated CEC
Standard 2:
pH(water/KCI), P(Bray 2/Truog/Olsen), Cations(Ca, Mg, K, Na), Exchangeable acidity, Density, %Ca, %Mg, %K, %Na, Ca:Mg, Mg:K, (Ca+Mg)/K, Calculated CEC
Additional Analysis:
Zn, Cu, Mn, Fe (HCI)
Zn, Cu, Mn, Fe (DTPA)
Zn, Cu, Mn, Fe, S, B (Melich III)
Available B (hot water extract)
Available S (Am Ac)
Texture (Clay, Silt, Sand)
Carbon (C)
Chloride (Cl)
Nitrogen (NH4 + NO3)
Colour & Finger Test
Stone fraction
EC (Saturated paste)
Exchangeable Al
S(Ca PO4)
Heavy Metals
1:2 Water ekstract
(Ca, Mg, K, Na, Cu, Zn, Mn, Fe, S, B)
Conductivity:NH4 – N, NO3– N,pH, Cl, HCO3, CO3
Mehlich III-Package
pH(KCI), P(Bray I of II), Cations (Ca,Mg,K,Na,Fe,Mn,Cu,Zn,B,S,P)


Discount prices can be negotiated for large quantities of samples.

Growth Media Analyses:

Standard :
EG, pH, K, Ca, Mg, Na, Cl, SO4, HCO3, CO3, PO4, NH4, NO3
Complete :
EG, pH, K, Ca, Mg, Na, Cl, SO4, HCO3, CO3, PO4, NH4, NO3, Fe, Cu, Mn, Zn, B
Physical Properties :
Air filled porosity, Water holding capacity and Bulk Density
C:N Ratio (Nitrogen and Calculated Carbon included)
Heavy Metals :
Ag, Al, Ba, Cd, Co, Cr, Ni, Pb, Be, Li, Sb, Se, Sr, Ti, V

Soils & Growth Media

Citrus and Avocado Samping