What is soil
Soil is a living ecosystem comprised of a mixture of minerals, water, air, organic matter, and countless organisms such as insects, worms, fungi, bacteria and protozoa.
Often you hear the terms soil and dirt used interchangeably, but they are not the same. Dirt is dead and provides no nutrients, whereas the soil is the total opposite and full of life. The importance of soil to our health and environment is profound.
There are many layers of soil. The first layer is called the organic layer, which is decaying plant matter such as leaves and other debris. The next layer is called topsoil which is what this post focuses on when referring to the soil. Topsoil holds organic matter, and organisms and is where most plants’ roots are.
Fun fat! There are more living organisms in a tablespoon of soil than there are people on the earth.
What makes soil healthy
Not all soil is created equal. There is healthy soil and unhealthy soil or living vs unliving soil. Healthy soils have the following characteristics
- Lots of organic matter
- Lots of beneficial organisms
- Has good drainage (not compacted)
- Void of toxic chemicals and pollutants
The Importance of soil
It may seem like what we walk on is not that important, but the soil has such an impact on our life. In order to have healthy people, we need healthy soils. Below you will read about what healthy soil does for human and environmental health.
Soil & Nutrition
Soil is essential to growing food. All those amazing vitamins and minerals found in food actually come from the soil. When our soil is depleted of nutrients, so is our food.
According to the Journal of the American College of Nutrition calcium, phosphorous, iron, riboflavin and vitamin C had a ‘reliable decline’ from 43 vegetables and fruits from 1950 to 1999.
Kushi Institute Analysis found that from 1975 to 1997, the average calcium levels in 12 vegetables decreased by 27%, iron by 37%, Vitamin A by 21%, and Vitamin C by 30%.
Produce and grains have also shown a higher concentration of carbon dioxide via photosynthesis. Extra carbon is like empty calories for humans. It gives us energy, but not much nutritional value.
Soil & the Environment
Soil is a growing medium for plants. All the trees, flowers, shrubs, and grasses that you see are dependent on the soil to grow and live. Even though we may not eat all plants, other species are dependent on them for both nutrition and habitat. Plants also help to mitigate climate change by absorbing carbon dioxide from the atmosphere.
Reduces greenhouse gases. If the soil has a good structure and a lot of organic matter it helps to capture carbon dioxide which is a main greenhouse gas. It essentially helps to take away carbon dioxide from the atmosphere and store it.
Healthy soil reduces erosion. Where there is a lot of organic matter, the soil can hold more water into its pores. When the soil is compacted and is void of organic matter, it cannot hold water and it will wash away during heavy rainfalls which lead to flooding and polluted water.
Soil aids in keeping water clean. Water is captured through pores in the soil. After it is captured, it is then filtered to create clean safe water free from pollutants that we can drink and use daily.
Soil provides a habitat for billions of organisms. As mentioned above billion of organisms live in soils. You may have seen an abundance of worms in a compost pile. That is what you can see through a naked eye, imagine if you were looking under a microscope how much you would see!
How Soil is Impacted/Affected
Soil is impacted mainly through agricultural practices. Growing food and raising livestock greatly impact how soil stays healthy and abundant. Like all things, there are positive agricultural practices that improve soil health and negative practices that decrease soil health.
Positive Agricultural Practices
Crop rotation/diversification – when you rotate your crops or plant a variety of crops (opposite of mono-cropping), it helps to improve the amount of organic matter and reduce the need for as many herbicides/pesticides.
Compost – compost is the end product when you let organic matter decompose. When you apply it to your garden or field, it increases organic matter and helps to improve soil structure.
Cover Crops – it is important to always keep the soil covered. Cover crops are crops that you plant when the field/garden bed is not in use. They improve the soil by adding organic matter, increase biodiversity, provide a home to other organisms, is a natural fertilizer and add nutrients and reduce soil compaction which makes it able to retain water better.
Reduction in tilling – if you are not tilling as much, you are not compacting the soil as much. Compacted soil leads to erosion and loss of soil structure.
Grazing of livestock – when livestock graze outside (not confined to a cage), their manure is returned back to the soil in quantities that are healthy. This in turn increases organic matter and is composted naturally.
Negative Agriculture Practices
Mono Cropping – This is when you plant the same crop over and over again and do not have any diversification. For example, a farm may have several acres of only soybeans and that is the only crop being grown. 75% of the world’s food is from 12 plants and 5 animal species and in the United States just under half of our total farmland is planted with soybeans, wheat, rice, corn.
This practice strips the soil of nutrients and organic matter is depleted. This is because there is a higher need for fertilizers/pesticides, and a decreased ability for the soil to hold water and the soil erodes much more quickly.
Leaving Soil Uncovered – When soil is bare, it is much more susceptible to erosion and loss of topsoil. Every time it rains or there are high winds, the topsoil will erode into our waters.
Frequent Tilling – Tilling is a practice that compacts the soil. Think of the big heavy machine going over and over again on the field. Every time this happens, soil structure is destroyed and the soil is much more prone to erosion and biological degradation.
Pesticide/Herbicide Runoff – Agriculture uses A LOT of chemicals. What is even worse is that 80 to 90% of applied pesticides hit non-target vegetation and stay as pesticide residue in the environment. Basically, that means when a farmer sprays a crop, 80 – 90% of it leaves the crop and goes elsewhere. This causes many problems including
- Threatens species such as Honey bees, Birds, Insects, Aquatic species
- Pollutes water & air
- Degrades soil by destroying soil microorganisms such as bacteria and fungi
- Creates pesticide-resistant crops
Due to these negative practices, our soil is degrading quickly. There is less and less land that is now suitable for farming. In the U.S top soil is being eroded 10x faster than it can be replaced. Without healthy soil, we are unable to have healthy crops, without healthy crops, we can not have healthy people.
Why poor practices
- Agricultural and Company Subsidies
- Increased demand for food/higher initial yield
- Technological advances
- The use of GMO crops
What we can do
Not all of us farm, but there are still ways we can help to improve soil health!
- Grow gardens not lawns
- Support farms that practice good soil health
- Even if you have a small garden, you can implement good practices like cover crops, crop rotation and adding compost
- Start composting to bring more organic matter to the land
- Avoid usage of pesticides and herbicides on your laws/gardens
Soil is important for humans and for the environment. Without soil, we would not be able to have vital things like food, plants, and clean water. There would not be a home to billions of organisms and there would be much more greenhouse gases in the atmosphere.
Agriculture is the biggest contributor to changes in the soil. Even if you do not own a farm, there are still ways you can help improve soil health through what you do in your own garden or law, or where you purchase your food from.