Even a novice gardener knows how important the quality of the soil is to growing plants and lawn. Soil is not a one size fits all proposition. There are different types of soil in different regions of the country that need to be tweaked to come up with the perfect soil necessary for healthy plants.
Soil consists of clay, sand, stone and acidic. The key is to balance that out so that you do not have too much of any one element.
Besides clay, sand, stone and acidic, soil also has organic matter, water and air. Out of this group, it is the organic matter — small animals, worms, insects and microbes –- that provides the magic. These elements thrive when the soil itself is balanced.
Experts say that minerals account for half of the soil of a garden. This would include small pieces of weathered rock that has been broken down by the wind, rain, freezing temperatures, thawing ice and other processes involving chemicals and biology.
The classification of the soil as clay, sand, or silt depends on the size of the inorganic soil bits. Sand indicates that the soil has large bits; silt signals that it has medium-sized pieces, and clay denotes very small particles. The percentage of sand, silt and clay determine the texture of the soil and influences its draining capability and the amount of nutrients present. This then influences how well your plants will grow.
As previously mentioned, organic material is essential for the health of soil. It is partially decomposed remains of organisms and plant life including lichens, mosses, grasses and leaves, trees, and vegetative matter.
Although the organic matter is essential, it only accounts for about 5 to 10 percent of the soil. What’s so good about it is that it binds the soil particles together into porous morsels or pellets. The pores permit air and water to move through. The organic material retains the moisture and absorbs and stores the nutrients. In addition, the organic matter is food for microorganisms and other soil life.
If you want to increase the amount of organic matter, simply add compost, aged animal manures, mulches or peat moss. Experts suggest that this should be spread over the top layer of the soil because most soil life and plant roots are within the top 6-inches of the soil.
Some may suggest the use of high-carbon material on the soil. This would include straw, leaves, wood chips and sawdust. However, be cautious about the amount you use because soil microorganisms consume a lot of nitrogen as they digest the carbs and that may deny the plants from getting nitrogen in the short run.
Organisms that are part of the soil life include bacteria, fungi, protozoa and nematodes, mites, springtails, earthworms, and other tiny critters normally found in healthy soil. These critters are vital for plant growth because they help to convert organic matter and soil minerals into vitamins, hormones, disease-suppressing compounds and nutrients that plants need to thrive.
In addition, the excrement that comes from these tiny creatures help to bind the soil. It is the responsibility of the gardener to offer the best conditions for these organisms to do their magic. They need to be given food (carbohydrates), oxygen (due to well-aerated soil), and water.
Air is an essential element for the organic soil life to live. The air is also a source of atmospheric nitrogen that the plants use.
Soil that is well aerated has plenty of pore space between the soil particles. However, clay or silt particles have tiny holes, maybe even too small for the air to penetrate. Large particle soil, like sand, has large pores that can contain plenty of air. You want the organisms to get air, but you don’t want them to get too much air because they can decompose too quickly.
To ensure that there is a proper balance of air, add plenty of organic matter to the soil. Don’t step in the growing beds of your garden or compact the soil and don’t disturb the soil when it is very wet.
Water accounts for about 25 percent of healthy soil. The water is held in the pores between the soil particles. Large pores permit rain and irrigation water to settle down to the root zone and into the subsoil. Sandy soil has very large pores that can allow water to drain down and out very quickly. As a result, sandy soil dries out very fast.
Small pores allow the water to journey through the soil in a capillary action. Soil with small pores can get over-saturated causing the pores to get completely filled with water. This forces air out causing the soil organisms and the plant roots to suffocate.
Preferably, you want the soil of your garden to have a combination of large and small pores. The key to this is the organic matter. It helps to form the soil and it absorbs and retains water until the plants’ roots need it.
The solution to having healthy soil is being certain that there is a proper balance of minerals, organic matter, soil life, air and water.
(Next time: Soil Texture and Type)