Soil Analysis

Measuring pH Methodology

1. pH probe can be placed in soil, with a reading taken from the scale (probe must be wiped between each use)

OR

1. Put 1 cm of soil into a test tube

2. Add 1 cm of barium sulphate to the test tube (this attaches to fine particles and makes them sink leaving a clear layer above it)

3. Add enough distilled water to bring the level half way to the top of the test tube

4. Add two pipettes full of indicator solution

5. Seal the test tube with a rubber bung and shake well (make sure that the contents are mixed thoroughly)

6. Allow the test tube to stand until the soil has settled out leaving a coloured solution

7. Hold the tube next to the colour chart and decide which pH colour it most closely matches.

8. Dispose of the soil in the bin.

Measuring Humus Content Methodology

1. Collect 5-10 grams of soil

2. Weigh dry soil sample (put them in oven prior)

3. Put soil in a very hot furnace of 550 degrees or burn it using a bunsen burner for roughly 30 minutes

4. Weigh soil - change in weight is mass of humus - a percentage of humus content can then be calculated using this weight and the dry sample

Soil Profile Methodology

A section is dug out of the soil using a Soil auger so that the different horizons can be seen.

Written descriptions can be recorded of the structure, texture, organic content, colour and depth of each horizon

Temperature and Moisture Methodology

1. Temperature and Moisture meter’s can be placed in soil and reading taken off scale

OR (for soil moisture)…

1. You can take 5-10 grams of soil then weigh it

2. Weigh the mass of a crucible, then put the soil in the crucible

3. Place the crucible into an oven for 10 minutes at 100 degrees

4. Remove soil from oven and weigh it

5. Change in mass is the soil moisture content of the soil

Infiltration Rates Methodology

1. Use infiltrometer by securing it firmly in the ground and pouring water into the top of the tube

2. The stopwatch should be began and every 30 seconds the water level should be checked

3. This can allow you to measure the infiltration rate in millimetres per minute

Soil Texture Methodology

1. A small sample of soil should be collected and an identification key used to ascertain the type of soil

2. A sieve can be used to split up the soil, which shows the percentage of different parts that make up the soil

Soil Smears Methodology

1. Moisten a soil sample in your hand

2. Use identification key to roll the soil into different shapes to determine how clayey, sandy or loamy the soil is

Considerations

• Gain permission of landowner before digging soil samples. Permission is needed to use soil augers

• Ensure probes for pH and soil moisture metres are clean before use

• It is important to keep the transect on a straight line across the sand dune system and to take a number of profiles across the width of the dunes for comparative purposes

• Soils samples should be handled with rubber gloves and sterilised before being processed

• Need access to a fume cupboard when burning humus in soils

Limitations

• Identifying separate horizons is difficult without being experienced.

• The process of identifying texture is difficult without practice and a level of subjectivity is involved

To ensure the results are reliable

• Ensure the sample is representative of the whole population.

• Repeat fieldwork at another time - the environment (e.g. beaches, sand dunes, hill slopes)

• Changes throughout the year, soils have higher moisture content in winter than summer.

• Do more samples or transects or spread them further apart to come to genuine conclusions

• Take averages

To ensure validity

• Using the same equipment or apparatus e.g. same size of quadrat, same soil probe,

• The equipment has been properly calibrated

• Ensuring all other variables are kept constant (if possible) e.g. Same time of day or

• Same stage in a tidal cycle allows valid comparisons to be made