Nutrient Fuel Gauges

With a fuel gauge installed, in-season nutrients can be monitored and measured with ease by our Area Mangers. The information they provide will allow you to make better decisions regarding your in-season fertilizer applications, with the aim of maximizing yield and profit.

All of our services are carried out by our network of full trained Area Managers

A fuel gauge is a strip placed in the paddock (typically 2m x 100m) containing a non-limiting rate of a specific nutrient. Fuel gauges can be carried out across a wide range of crops as a way to monitor in-season nutrients. They also allow Area Managers to measure nutrient response against farmer practice.

How do they work?

A strip of non-limiting nitrogen has been applied in-season, to measure the potential benefit to the crop.

Once the nutrient rich strip has been applied, they are read throughout the growing season with a GreenSeeker®. NDVI readings are taken on and off the strip and and inputted into the nitrogen calculator, along with other information such as the paddock sowing date. The software then predicts the response to nitrogen and calculates the rate required to achive optimum yield and returns.

Summit has carried out extensive field research trials under Western Austrialan conditions to test the validity and accuracy of fuel gauge recommendations.

Types of fuel gauges

The majority of fuel gauges are nitrogen, as remedial action can be carried out within the season. Potassium, phosphorus and other nutrient fuel gauges can also be carried out, with responses actioned for the following season.

If you’re interested in setting up a fuel gauge on your farm, or would like to learn more, get in contact with your local Area Manager.

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(salt)
dS/m
Levels <0.2 are="" generally="" considered="" negligible.="" levels="">0.8 can be said to be accumulating salt, and should be investigated further.</0.2>
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
(CaCl2)
5.0

As pH declines (becomes more acidic) Aluminium levels can increase in some soil types. High Aluminium levels will affect root growth reducing their ability to explore large volumes of soil and therefore their access to nutrients and soil moisture. (Read the article on soil pH here)

PBI

PBI is a function of soil type. Generally as a soil contains more iron, clay and organic matter, the higher the PBI. (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