Soils consist of a thin layer on the earth’s surface called a pedosphere and are an integral part of the ecosystem. Soils hold nutrients and water for plants and animals and profoundly affect the atmosphere, the water we drink and the foods we eat.
Click here for the General Directives for Soil Protocols!
How to Collect Soil Moisture Samples
1) Star and Transect Sampling
Students must first note the surface cover type and scrape or pull away any long grass or bare soil. Students can then dig a hole 10 cm in diameter and 5 cm deep. Students must remove any rocks or pebbles before filling their soil collection containers with 100 g of soil. Students must then number the container and record the date, time, depth and can number. After taking this sample, students will again dig down to a depth of about 8 cm and then dig that soil down an additional 4 cm. Students will repeat the above procedure with this deeper soil. Students can then take soil temperature measurements within 25 cm of each soil sampling.
2) Depth Sampling
Students will repeat the above procedures but will use an auger to obtain soil samples from 10 cm, 30 cm, 60 cm and 90 cm of depth from the same hole. Students can then take soil temperature measurements at depths of 5cm and 10 cm within the sampling point.
How to Weigh and Dry the Samples
1) Wet Weight
Students can find the wet weight of their soil samples by first removing any tape from the can that contains the sample soil. When students weigh the soil collection container with the soil sample they will find the wet weight. Students must record the date and time at which the sample was collected, the container number and the wet weight of the sample to the nearest 0.1 g.
2) Dry Weight
Students can dry the sample with either a ventilating drying oven or a dehydrating oven. When students re-weigh the soil collection container with the soil in it, they will obtain the dry weight. Students must record the drying time, the type of drying oven used, and the dry weight to the nearest 0.1 g.
3) Water Weight
The water weight is obtained by subtracting the dry weight from the wet weight.
4) Container Weight
When students empty out the soils from each container and weigh the dry soil container, they will discover the container weight.
7) Dry Soil Weight
Students will find the dry soil weight by subtracting the container weight from the dry weight.
8) Soil Water Content
Students can then find the soil water content by dividing the water weight by the dry soil weight.
![Protocols [Image: Blue-Eyed Grass]](images/protocols_h.jpg)
