Soil Analysis Field & Lab Work
Aim: To measure changes in pH, temperature and salinity (conductivity) in soil
samples, along an environmental gradient, using sensors for datalogging
(for MultiLogPRO and LabPro with TI84)
Background: Abiotic factors change along environmental gradients.
Definition: “An environmental gradient is a gradual change in abiotic factors through space (or time). Environmental
gradients can be related to factors such as altitude, temperature, depth, ocean proximity and soil humidity (etc.).
Species abundances usually change along environmental gradients in a more or less predictive way. However, the species
abundance along an environmental gradient is not only determined by the abiotic factor but, also by the change in the
biotic interactions along the environmental gradient.
At an ecotone, species abundances change relatively quick compared to the environmental gradient.
The species distribution along environmental gradients has been studied intensively due to large databases of species
presence data (e.g. GBIF).” (Source: http://en.wikipedia.org/wiki/Environmental_gradient)
Further background & Methods are provided in the following Vernier labs:
#8 – Soil Temperature
#9 – Soil Salinity
#10 – Soil pH
Source: http://www.vernier.com/resources/ibes.html
Instructions:
Pre-prepare a table for recording quantitative abiotic data, both in the field and in the lab. Also, for
recording observations of any related biotic data.
In the field, collect a number of soil samples for lab analysis (in sufficient quantities – refer to the
Vernier lab methods 9 and 10), along an environmental gradient in the area being studied.
* Temperature measurements are to be taken in the field.
In the lab, conduct the analysis for pH and salinity (conductivity) utilising the appropriate sensors
and datalogging equipment.
Follow up activity:
Plan an investigation to determine the effect of an abiotic factor of soil on a biotic factor, along an
environmental gradient.