Mrs. Irwin's integrating science in garden restoration |
Soil
Composition
Soil Composition
Soil is matter made from decomposers. From the NGSS standards for ecosystems disciplinary core ideas LS2.B: Decomposers recycle nutrients of dead plant or animal matter back into soil in terrestrial environments.Soil is the base at which our garden will begin to grow. Soil houses water, nutrients and the stable structure at which the roots of plants can burrow themselves into. We tested the following:
- Soil Type
- Water Volume
- Air Volume
- pH
- Nitrogen Content
- Potassium Content
- Phosphorus Content
- Measure of Inorganic vs. Organic Material
Soil Type
The big idea behind how the type of soil influences plant growth is as follows: soil supports plant growth and therefore is a fundamental building block for life on Earth. A more dense soil will make a difficult environment for porous air spaces and water saturation to occur. From our test we found the following:
•100 mL soil was mixed in a large graduated cylinder with 100 mL water and a drop of dish soap
•Left over the weekend to settle
–% Sand: 15 mL at 15%
–% Silt: 20 mL at 20%
–% Clay: 45 mL at 45%
–The rest of the % is air space at 20%
The soil is Sandy Loam. This soil should offer structural stability and porous room for root growth and flow of water and air.
•100 mL soil was mixed in a large graduated cylinder with 100 mL water and a drop of dish soap
•Left over the weekend to settle
–% Sand: 15 mL at 15%
–% Silt: 20 mL at 20%
–% Clay: 45 mL at 45%
–The rest of the % is air space at 20%
The soil is Sandy Loam. This soil should offer structural stability and porous room for root growth and flow of water and air.
Water and air volume
Soil can contain and transport water in porous spaces. To test the amount of water in a sample of soil from the garden plot, we weighed the sample of damp soil on a pocket scale then left the sample out to dry over the weekend. On the preceding day of class we measured the dry sample. The difference in weight suggested the percentage of water saturation in the soil.
•Weight of damp soil: 29.3 g (Monday March 23)
•Weight of dry soil: 19.2 g (Wednesday March 25)
Percentage of water with the soil sample: 5.2%
To test the volume of air within the sample of soil a syringe was filled with a sample of the soil, the volume of soil was measured before and after pressing down the plunger
–Before: 9 mL soil
–Compressed: 3.4 mL soil
•5.6 mL of air was in the sample
•Weight of damp soil: 29.3 g (Monday March 23)
•Weight of dry soil: 19.2 g (Wednesday March 25)
Percentage of water with the soil sample: 5.2%
To test the volume of air within the sample of soil a syringe was filled with a sample of the soil, the volume of soil was measured before and after pressing down the plunger
–Before: 9 mL soil
–Compressed: 3.4 mL soil
•5.6 mL of air was in the sample
pH and Chemical compostion
Plants grow from nutrients in the soil. Nitrogen, Phosphorous, and Potassium are macronutrients found in soil as a result of decomposers that help support healthy plant growth. Measurements of pH and chemical composition at sites in the garden were taken by 6 different groups in the class. Most found the following:
Nitrogen: medium amounts
Phosphorus: trace amounts
Potassium: medium amounts
pH: 6.0-7.0
It is possible that, at the time the measurements were taken, not a whole lot of work had been done by decomposers at the cold temperatures in early spring. From tilling the soils and weeding, we were able to mix in a fair amount of organic matter from dead plants that can be decomposed to offer more nutrients for our soils. pH can also be effected by the water quality filtering into the soils.
Nitrogen: medium amounts
Phosphorus: trace amounts
Potassium: medium amounts
pH: 6.0-7.0
It is possible that, at the time the measurements were taken, not a whole lot of work had been done by decomposers at the cold temperatures in early spring. From tilling the soils and weeding, we were able to mix in a fair amount of organic matter from dead plants that can be decomposed to offer more nutrients for our soils. pH can also be effected by the water quality filtering into the soils.
organic vs. inorganic
The floating substance is organic material and the inorganic is isolated at the bottom. Organic material comes from the dead plant and animal life existing in the soil. The organic material will be decomposed by decomposers such as worms and insect larvae There was less organic material at the beginning of the project then currently in the garden. This is what we found from the test:
•A sample of 50 mL of soil was added to water in a graduated cylinder. Left over the weekend to settle, the floating soil is measured as the organic material and the material at the bottom is measured as the inorganic.
–Organic: 2mL at 4.0%
–Inorganic: 40mL at 80%
In order to promote the amount of inorganic material within the garden we can turn to using compost to help offer a food source for decomposers
•A sample of 50 mL of soil was added to water in a graduated cylinder. Left over the weekend to settle, the floating soil is measured as the organic material and the material at the bottom is measured as the inorganic.
–Organic: 2mL at 4.0%
–Inorganic: 40mL at 80%
In order to promote the amount of inorganic material within the garden we can turn to using compost to help offer a food source for decomposers
Additional resource on the soil within MSU campus
The following document is the research that I completed in the fall of 2014 on the soils at three different sites on Michigan State University's campus. We completed many of the similar test on the composition of the soil minerals, organic material, and the animals found living within the soil.
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