You can show your students that the organic material in the soil also contributes to its ability to retain water. Put a small amount of dampened (not soaked) peat moss or sphagnum moss in one of the cup set-ups and pour a measured amount of water through. Students will see that the organic material helps soil to hold more water.
In the basic water cycle, water falls on the land in some type of precipitation (rain or snow). It either is soaked into the ground or runs off into a body of water – storm water or natural. Eventually, it returns to the atmosphere. But the story about water movement in soil is complex. Soil scientists call this topic “soil hydrology.
Water passed most quickly through the large pieces of gravel and most slowly through the very fine powdered clay. Turn students’ attention to the natural soil that represents a mixture of particle sizes. Did it let as much water through as gravel and sand?
Jan. 4, 2021 - A new study shows the importance of long-term soil moisture changes and associated soil moisture-atmosphere feedbacks in future predictions of water availability in drylands. The researchers ...
Experts now explain how soil texture, soil structure, and gravity influence water movement. In the basic water cycle, water falls on the land in some type of precipitation (rain or snow). It either is soaked into the ground or runs off into a body of water -- storm water or natural. Eventually, it returns to the atmosphere.
According to James Hartsig, a soil scientist with Duraroot Environmental Consulting, soil particles are either sand, silt, or clay. The relative amount of sand, silt, and clay in a given area makes up the soil texture. And, different textures of soil will have different size pores between particles. "These pores exist in gaps where soils particles ...
In the basic water cycle, water falls on the land in some type of precipitation (rain or snow). It either is soaked into the ground or runs off into a body of water – storm water or natural. Eventually, it returns to the atmosphere.
And, different textures of soil will have different size pores between particles. "These pores exist in gaps where soils particles come together. The large pores of a sand-dominated soil, where the particles are larger might allow more water flow than the micropore space in a clay-dominated soil, where particles are smaller and held together tightly."
Complete this investigation by asking your students to reflect on the investigation question and how their answers may have changed as a result of what they have learned. Ask them why they think it’s important for water to move through soil. Remind the students that how well a soil holds onto water and how well it drains water helps plants to grow. Elementary students know the importance of watering plants with just the right amount of water—not too much and not too little.
The finest part of a soil sample is probably mostly very small flakes of clay. They are too small for you to see even with a hand lens. Sandy soils are loose and easy to dig. Soils with a lot of clay are harder to dig. Some plants like sandy soils and others like soils with more clay. Most soils have lots of organic matter. Some of the organic matter is in the form of living things, such as earthworms, insects, and microorganisms. Most soils are also rich in decaying plants. If the plant has decayed only slightly, you can usually recognize scraps of leaves, roots, and seeds. When the plant has decayed more, it turns into a soft, fine, dark material called humus. Humus is very important in soils. New plants can easily put their roots into humus. It is also good at holding water for later use by growing plants.
Soil is likely to have several kinds of rock and mineral particles. A few kinds are very common. The three most common kinds are quartz particles, feldspar particles , and small pieces of rock. A soil sample is very likely to have a lot of at least one of these three kinds of particles. Quartz parti cles have irregular shapes. They look gray and glassy. Their surfaces are often stained brown or orange, because they are coated with rust. Feldspar particles are usually white or cream-colored. Their surfaces are often flat, at least partly, rather than irregular. There are many kinds of rock particles. You can tell them apart from the mineral particles because rocks are made of many different particles of minerals, all stuck tightly together.
If you have a potted plant growing in the classroom, show it to the class. Pick up the pot, and have the students notice that there is a hole in the bottom of the pot. Ask why the hole is there, and why they think you put a saucer under the plant. (Students will probably know that the hole allows water to drain.) Ask the students what would happen if you watered the plant and there was no drainage hole in the pot. (They will say that the soil gets “soggy”, “too wet”, “full of water”. They may even say that this would not be good for the plant.)
Matric: water drawn through the soil via adhesion to mineral surfaces and cohesion to itself.
Water creates a path based on conditions that are favorable to it.
Water in an unsaturated soil is subject to capillarity and adsorption which combine to produce a "negative" matric potential, or matric suction.
1) Macroporosity: Large pores account for almost all movement in saturated pores.
Asymmetry in the water characteristic curve. These differences in wetting and drying can be attributed to pore geometry. They have bottlenecks and trap air from entering or exiting easily.