Soil.
Soil is not the same as dirt. Dirt has a negative meaning. It is something to avoid.
Soil is a positive--literally, a source of life. Good soil is fundamental to a good garden.
Earth Science Dimensions of Soil.
Soil is a positive--literally, a source of life. Good soil is fundamental to a good garden.
Earth Science Dimensions of Soil.
- Texture. Soil texture comes in three forms: sand, clay, and loam.
- Sand is made of large particles which allow air and water to pass easily. But nutrients also slip through easily, so most plants starve in sandy soil.
- Clay is made of tiny particles which cling tightly to each other, holding on to nutrients but preventing water and air from moving through easily. So plants die of lack of water and air at their roots.
- Loam is made of medium-sized particles, holding on to nutrients, air, and water. Loam is the best soil for most plants, including vegetables.
- Soil pH. Soil pH is a number between 0 and 14 which indicates whether the soil is acidic (below 7) or alkaline (above 7). The term pH refers to the proportion of hydrogen ions in the soil. The pH determines whether or not a plant can absorb nutrients available in the soil. Most vegetables prefer a slightly acidic soil (pH 6.0-6.5).
- Soil nutrients. Plants, like people, need to eat. Plants must absorb a variety of minerals from the soil in order to grow.
- Most fertilizers are coded with three numbers, such as 10-10-10. These numbers indicate how much nitrogen (N, the first number), Phosphorus (P, the second number), and potassium (K, the third number) is in the plant food. Most important is nitrogen, which is essential for photosynthesis. Plants can absorb some N from the air, but most of it is pulled into the plant through its roots in the soil. The other two are also essential to a healthy plant.
- Trace minerals are also important, sometimes determining whether the plant will live or die and almost always affecting how well the plant can produce flowers, fruit, and seeds.
Life Science Dimensions of Soil.
Soil is a complex ecosystem that includes minerals, air, water and many, many types of animals. Some of the animals, like earthworms and pill bugs, we can see with our naked eye. But most of the creatures are so small we can't see them without a hand lens or microscope. The largest of these underground creatures is a mat of fungus in the Pacific Northwest that extends 9.7 square miles. (http://www.bbc.com/earth/story/20141114-the-biggest-organism-in-the-world)
Chemical fertilizers can damage this ecosystem.
Soil is a complex ecosystem that includes minerals, air, water and many, many types of animals. Some of the animals, like earthworms and pill bugs, we can see with our naked eye. But most of the creatures are so small we can't see them without a hand lens or microscope. The largest of these underground creatures is a mat of fungus in the Pacific Northwest that extends 9.7 square miles. (http://www.bbc.com/earth/story/20141114-the-biggest-organism-in-the-world)
Chemical fertilizers can damage this ecosystem.
Geographic Dimensions of Soil.
Climate and weather.
Climate and weather.