Pedogenesis is the process of soil creation.
Twenty years ago, there were over 20,000 different types of soil arrangements (called "soil series"), with specific characteristics and symbiotic relationships that evolved over thousands of years. These soil series can be destroyed in a matter of seconds with a bulldozer. There are currently over 3,000 extinct soil series in the USA alone.
Pedogenesis creates healthy soil that provides us with clean air, water, food and more, so start composting!
Soil has holes it.
Sandy soil can have so many macropores and micropores that water and nutrients leach away. Heavy clay soil, at the opposite end of the spectrum, has more micropores, so water is held tightly. Loamy soil, in the middle, provides both micropores and macropores for the healthiest soil.
Evapotranspiration refers to the combined effects of water lost through soil evaporation and transpiration of water through leaf stomates.
A large, well-watered tree can lose 100 gallons of water each day in hot weather through evapotranspiration.
Alluvium soil is a deposit of clay, silt, sand, and gravel left by flowing streams in a river valley or delta, typically producing fertile soil.
This is some of the most fertile soil on earth. In fact, over 12,000 years ago, our agricultural beginnings nearly all started around creeks and rivers. (Carrying water is hard work).
Rain, snow, and flowing water erode rocks, carrying minerals downhill, where they collect in lowlands with regular supplies of water. Nutrient rich alluvial soil plus readily available water and you have it - a garden!
Vermiculture refers to the care and feeding of worms!
Microorganisms are TINY life forms.
Bacteria, fungi, algae, protozoa, and other microscopic critters (microbes) are all microorganisms found in soil. The jury is still out on whether viruses are alive or not - but they are considered a microbe. According to Principles and Applications of Soil Microbiology (1998), you will find this many microorganisms in one gram of soil [1/5 the weight of an American nickel]:
• 100,000,000 - 1,000,000,000 bacteria
• 100,000 - 1,000,000 fungi
• 1,000 - 1,000,000 algae
• 1,000 - 100,000 protozoa
Try wrapping your brain around THOSE numbers! They must be having one heck of a party down there…
Some microorganisms can damage or kill plants. Bacteria can cause fireblight, cankers and soft rot. Fungal diseases include powdery mildew, Eutypa Dieback and rust. Viruses can cause Tomato Spotted Wilt, Cucumber Mosaic and many more.
Other microorganisms are critical to soil health because they make nutrients available to plants through the Nitrogen Cycle. Plants also exchange carbon, created through photosynthesis, for mineral nutrients from soil microbes. Other microbes stimulate plant immune systems and reduce stress to plants.
One soil microorganism in particular, Mycobacterium vaccae, has recently been found capable of uplifting your mood! Most gardeners claim that gardening is their therapy. Ends up, they were right!
Microorganisms, like other living things, can be poisoned with herbicides, pesticides, and fungicides. The best way to keep a healthy balance of microorganisms in your soil is to keep the soil healthy. Very often, chemicals cause too much change too quickly. Regularly adding compost to your soil is the best way to keep your soil healthy.
Gardens may look peaceful and calm, but there’s really a lot going on, especially at the level of atoms and molecules. Don’t let this freak you out or chase you away. It’s actually pretty amazing.
If you’ve ever taken a chemistry class, you know that atoms and molecules can be stable or unstable. Unstable atoms and molecules have the wrong number of electrons spinning around. When an atom or molecule is unstable, it is called an ion.
So what in the world does this have to do with gardening?
Simple. Soil, minerals, and plants are all made up of atoms and molecules, just like us humans. Nutrients in solution, such as liquid fertilizer, or rain or irrigation water passing through compost, have a tendency to stick to the surrounding solids. This is called adsorption.
Don’t let the word confuse you. While adsorption looks a lot like absorption, they behave very differently. Imagine yourself at a party. As you enjoy a sip of your drink (absorption), you spill some on your shoe (adsorption).
Generally speaking, soil is negatively charged. This means soil is using adsorption to grab electrons from nearby atoms and molecules of minerals. Adsorption is a good thing because it gets the nutrients closer to where the plants need them. This is especially relevant when adding amendments or fertilizer to poor soil.
(In English: it doesn't help to add it if your plants can't get to it!)
Unless you are using hydroponics, all of your plants will grow in some sort of soil. The better we understand our soil, the easier it will be for us to take good care of it (and easier is good).
Soil tends to form layers on top of bedrock. These layers of soil are called horizons. Just above the bedrock is a layer of unbroken rock. There are generally no plant roots here. This is called the regolith.
The infographic below shows the basic soil horizons:
The U.S. Department of Agriculture has an amazing interactive map that can help you learn more about your local soil.
I hope this information inspires you to grow more of your own food. You can ask your garden questions on my Home page.