VSA (Visual Soil Assessment)
A good way to analyse soil, without testing in a lab, is to do a Visual Soil Assessment (VSA). Conducting a single VSA is enough to explore the visual indicators of soil quality. Assessing several sites around the school grounds can show the effects of land use on soil quality. For example, compare the soil under a fence line or in an out-of-bounds area with the soil in a high traffic area. Here are the instructions on how to perform your own visual soil assessment.
http://www.sciencelearn.org.nz/Contexts/Soil-Farming-and-Science/Teaching-and-Learning-Approaches/Visual-soil-assessment
We performed three VSA's in Memorial park. We analysed soil from the three different areas, one by the Waikato River, one near a flower bed, and one in a sandy clay patch with no grass. Our results are as follows:
Memorial Park
By the river: The soil porosity was average as there weren't many cracks or pores i the soil, but some were still visible. The soil structure was not the best but still had a reasonable structure. There were reasonably big aggregates, however most were small and crumbled easily when pressure was applied. The number of earthworms was below average, as we only found 6. We noticed the soil was a bit hard to dig, but had a healthy brown colour and the soil was moist.
By the flowerbed: The soil porosity was extremely good as many cracks were visible as we dug and there were also many pores in the aggregates. The structure of the soil was excellent as there was a limited amount of large aggregates and the remainder of the soil was fine and crumbly. The number of earthworms was slightly above average with a total of 17 earthworms.
Sandy, clay soil: The soil porosity was extremely bad. The soil was dense and full of rocks, with no visible cracks or pores. The soil structure was also really poor because there was wet sand packed into the soil and numerous rocks. There were no earthworms at all which showed that the soil quality was low.
Outside Cherrington: The soil porosity was very dry but there was a couple of visible cracks. The soil had an average structure with a few large aggregates but also very fine, crumbly soil particles in it. We found only 3 earthworms but because the gardener has been tending to this soil, this could've influenced our results. The main point of interest that we observed was that the soil was very, very dry and crumbly, most likely due to the amount of work done to it by the gardener.
Memorial Park
By the river: The soil porosity was average as there weren't many cracks or pores i the soil, but some were still visible. The soil structure was not the best but still had a reasonable structure. There were reasonably big aggregates, however most were small and crumbled easily when pressure was applied. The number of earthworms was below average, as we only found 6. We noticed the soil was a bit hard to dig, but had a healthy brown colour and the soil was moist.
By the flowerbed: The soil porosity was extremely good as many cracks were visible as we dug and there were also many pores in the aggregates. The structure of the soil was excellent as there was a limited amount of large aggregates and the remainder of the soil was fine and crumbly. The number of earthworms was slightly above average with a total of 17 earthworms.
Sandy, clay soil: The soil porosity was extremely bad. The soil was dense and full of rocks, with no visible cracks or pores. The soil structure was also really poor because there was wet sand packed into the soil and numerous rocks. There were no earthworms at all which showed that the soil quality was low.
Outside Cherrington: The soil porosity was very dry but there was a couple of visible cracks. The soil had an average structure with a few large aggregates but also very fine, crumbly soil particles in it. We found only 3 earthworms but because the gardener has been tending to this soil, this could've influenced our results. The main point of interest that we observed was that the soil was very, very dry and crumbly, most likely due to the amount of work done to it by the gardener.