U2L9 Soil Lab

KU TI C A 10 10 10 10 Name: Date: Course Code: SNC1W: U2L9 Lab Dang Lien 8/6/2025 SNC1W-07 [2 C] Title of U2L9 Testing soil for texture & pH Experiment: Purpose: To know which characteristics does a sample of soil possess. [1 C] Prelab Questions 1. Watch the video at https://www.youtube.com/watch?v=VObLitSe3K0&t=10s. This video is about 15 min long. Summarize 4 main ideas (there are many more) from the video. You may use bullet form. [4 I, 4 C] 1 2 3 4 If we want to grow food, we have to sustain the community of life in soil. Soil is formed from some material that is in a particular location and is not renewable . Those materials can come from wind, water, glaciers, etc. Biodiversity is necessary in creating biologically healthy soil. There are some ways such as changing crops rotation, growing winter cover crops or using perennial crops. As the cost of the energy the energy that we use to grow food goes up, eventually we have to bring about changes and care for soil. 2. In your own words, why should we care about soil? [2 A, 2 C] We should care about soil because essential to every life on Earth. With the rising cost of energy, preserving the remaining soil is one of the most effective solution to prevent food to become a luxury. Soil is also the second largest carbon sink in the world, and if the soil degradation continues, all of that carbon is released to the atmosphere. In addition to that, if there is no soil, a lot of land would be subjected to flooding or become desserts. As soil is undoubtedly precious and crucial to many parts of our lives, we should protect and preserve soil as well as mitigate the negative causes to soil degradation such as pollution, climate change, excessive farming. Observations Watch the video in U2L9 and the slides to complete the data table below. Table 1: Station 1 Lab Observations. [5 K] Soil Type Volume (mL) Percentage (Show calculation) Rock 0 mL (0÷20)×100%=0% Sand 11 mL (11÷20)×100%=55% Silt 3 mL (3÷20)×100%=15% Clay 4 mL (4÷20)×100%=20% Humus 2 mL (2÷20)×100%=10% Table 2: Station 2 Lab Observations. (Slide 6) [1 K, 1 C] Soil Type Observed Colour and pH Top Soil Color: Light orange pH: 4 Analysis 1. Why was water used in station 1? What would happen if you did not shake the sample enough? [2 K] Water is used in station 1 because water is much smaller than others molecules so it is able to get between soil particles and mixed them up, allowing different soil particles to settle down in layers so that we can observe and determined the sample's texture. Water is also used because it is a very simple and fairly accurate soil texture test so anyone can do it at home. If you did not shake the sample enough, the different particles would not got mixed up and separated thoroughly, some particles would also be stuck at the bottom of the cylinder. When you put the 2.sample Woulddown, the results for station 1 consistent for topsoil fromdown any locations? Explain why whytest not.results [2 K] as various types of particles would not fall separately leading toor false you can not tell the particles apart. The results for station 1 for topsoil would not be consistent from any locations. Because there are many factors responsible for each characteristics a soil sample may has such as climate, location, organisms inside the soil, time, parent materials, etc. For example, a sample from a forest would have a larger hummus percentage than a sample from a coastal area. 3. How would you expect the percentages to be different if the sample came from a vegetable garden? [2 I] If the sample came from a vegetable garden, I would expect the percentages of sand, silt and clay to be quite similar and combined they make up most of the non-organic materials in the sample, leaving rock percentage to be quite small. The soil that is best for agriculture is loam soil and I think a sample from a vegetable garden would be close to it in contents. (sand, silt and clay help the soil to retain water and nutrients while also not being too compact.) On top of that, there would also be a noticeable percentage of hummus as it is needed for the nutrients it provides to the vegetables and also because of additional compost that the owner puts 4. in. Take a look at the soil profile in the diagram below. For the B and C Horizons, how would you expect the percentages of sand, silt, humus, and gravel to be different (higher/lower) from the topsoil sample examined in this experiment and from each other? [4 A] For the B Horizon, I would expect humus and sand percentages to be lower than those of the topsoil sample while the percentages of silt and gravel would be higher because the B Horizon is more compact and there is not much organic matter there. There is also the process of illuviation, where clay and minerals are accumulated in the subsoil. For the C Horizon, which is also called the Substratum, hummus percentage would be 0% since the layer lacks organic material. Since this layer is mostly consist of weathered and unweathered rock, I would also expect sand percentage to be lower than that of the topsoil sample. By the same fact of this layer is mostly rocks, I would think that C Horizons has higher silt and gravel percentages than the topsoil sample. Comparing C Horizon and B Horizon together, evidently the percentages of humus and sand in B Horizon would be higher while silt and gravel percentages would be lower. As A Horizon and B Horizon soils are sometimes mixed up in farming and are more similar to each other than to C Horizon, the comparison between C Horizon-A Horizon and C Horizon-B Horizon is also the same. B Horizon: Subsoil that is rich in minerals and harder to dig through than topsoil. C Horizon: Includes parents material, lacks organic material and has little to no soil formation. Image from: https://rsandss.blogspot.com/p/soil_18.html?m=1 5. What do you think is a problem for soils that are high in clay content? Explain. [4 A] A big problem with soils that are high in clay content is they are highly susceptible to rain. The soil may be sticky when wet and brick-like when dry. They also have high water retention and the tendency to shrinking or swelling. Clayey soils usually hold onto water so they are very heavy and hard to work with, it also took longer for them to warm up and may delay your plans for them. Furthermore, Soils high in clay content are in risks of cracking and compacting which damages roots growth, drainage and soils health. If not treated the right way, crops would die from the lack of oxygen, drowned roots, etc. 6. Consider the chart below and the pH measurement of your soil (table 2). Image : Lawnlove.com a. What are two issues with your topsoil related to the pH? [2 I] 1. High concentrations of aluminum, iron and manganese which could be toxic to some plants. 2. Reduced microorganisms which result in less nutrients and favorable minerals. b. How could you remediate your soil? (2 ideas) [2 I] 1. Apply ground agriculture limestone into the soil to raise its pH level. 2. Apply wood ashes into the soil to raise its pH level.