Plant Analysis

Our comprehensive plant analysis service measures the amount of nutrients contained in the plant at the time of sampling and is the best indicator of trace elements currently available.

At Summit, we offer a comprehensive plant analysis service. Plant analysis measures the amount of nutrients contained in the plant at the time of sampling and is the best indicator of trace elements currently available. This service is also useful for:

  • Predicting plant nutritional problems during the early growing season.
  • Monitoring the effectiveness of the current fertilizer strategy.
  • Determining what nutrients are available to grazing animals.
  • Locating specific areas of the paddock where deficiencies of one or more nutrients may occur.
  • Optimizing yields.

With over 30 years of experience in the industry, you can rely on our team to deliver a world class plant testing service.

Benefits of a Summit Plant Analysis

  • Independent laboratory testing
  • Rapid turnaround times
  • Wide range of nutrients measured
  • Continued support from Area Managers trained in plant sampling techniques

Plant test reports available to view and download online via SummitConnect

Nutrient
Symbol
Units Used
Adequate Range Expected
Comments
Phosphorus

P

ppm (mg/kg)

15 - 45

Dependent on crop/pasture type and soil type.
Potassium

K

ppm (mg/kg)

40 - 120

Lupins and Canola are less sensitive to K deficiency. Clover and Medic require higher soil levels.
Sulphur

S

ppm (mg/kg)

5 - 15

Dependent on soil type.
Nitrate

NO3

ppm (mg/kg)

up to 30

Very mobile in the soil. May be lost to leaching.
Ammonium

NH4

ppm (mg/kg)

up to 20

Stable in the soil as it is a cation, but converts to Nitrate readily.

Copper

Cu

ppm (mg/kg)

> 0.3

Soil tests for Copper are a guide only.
Zinc

Zn

ppm (mg/kg)

0.12-0.5

Dependent on soil pH. The more alkaline the soil (higher pH) the higher the soil Zinc level needs to be.
Organic Carbon

O.C.

%

1.0 - 3.0

Dependent on soil type and rainfall.
Electrical Conductivity

EC (1:5)

dS/m

< 0.25

A measure of 'salinity'. Highly dependent on soil type with heavier soils having some buffering capability, but generally EC (1:5) values <0.2 are non-saline and >0.7 is of concern and possibly accumulating salt.

A variable conversion factor can be applied so values will fit one scale across all soil types. This is called 'estimated EC' or ECe. In this case ECe threshold of >8 represents highly saline soil.
pH

(CaCl2)

>5.0

Economic responses to applying lime to increase pH above 5.0 are doubtful. If subsoil pH is low, it may be necessary to increase topsoil pH >5.5 (CaCl2)
Aluminium

Al

ppm (mg/kg)

<5.0

As pH declines (becomes more acidic) aluminium can increase in soil solution. Aluminium is toxic to roots. When roots don't grow, plants cannot explore the soil to access nutrients and soil moisture. Levels above 5 mg/kg strongly impact wheat. Other crops such as barley are more sensitive (Read the article on soil pH here)

PBI

PBI (Phosphorus Buffering Index) is a function of soil type. Generally where soil particles contain more iron, aluminium and calcium such as forest gravels, plus some soils with considerable clay and organic matter, the PBI will be higher and decrease plant-available P  (See article)

Nutrient
Symbol
Units Used
Nitrogen
N
%
Phosphorus
P
%
Potassium
K
%
Sulphur
S
%
Calcium
Ca
%
Magnesium
Mg
%
Copper
Cu
ppm
Zinc
Zn
ppm
Manganese
Mn
ppm
Boron
B
ppm
Sodium
Na
ppm
Iron
Fe
ppm
Nitrate
NO3
ppm
Chloride
Cl
%
Options
Molybdenum
Mo
ppm