The United Nations Food and Agriculture Organization named 2015 Year of Soil. Why? What’s so important about dirt?
Dirt. You wash it off your hands, walk on it and probably feel squeamish when too much of it gets on your skin. Not something you think about too often. But soil is an important resource for everything from human health to agriculture to water filtration. In fact, the Catskill Watershed
in New York provides New York City with clean water at one-sixth the price of what a new water filtration plant would cost. Not to mention the obvious benefits of the food we grow out of soil. We literally owe our lives to healthy soil. Yet we continue to threaten it.
The important role of soil
First, let’s take a look at the role healthy soil plays in our lives.
The most well-known and imperative benefit of healthy soil is food production. Healthy soil is full of organisms that turn dead matter and minerals into vital plant nutrients.
A shocking use for healthy soil is to use it to protect against drought. Healthy soils can absorb and store water, which acts as a mock reservoir during dry stints. The United Stated Department of Agriculture
(USDA) states that for every 1 percent increase in organic matter in soil, U.S. farms could store the amount of water that goes over Niagara Falls in 150 days.
Dr. Bianca Moebius-Clune, the National Resources Conservation Service’s soil health division director, said, “Organic matter and living organisms provide the foundation for soil to function properly, allowing it to take in, store and deliver water to plants, among many other benefits.” The secret is that organic matter makes soil form “stable soil aggregates, or crumbs.” Soil can then absorb and hold more water.
We can also fight infections with dirt. How counterintuitive is that? Antibiotics can be developed from bacteria found in soil. Scientists are looking for soil bacteria in natural areas for this purpose
. As of the beginning of this year, an area in New Mexico and an Atlantic forest region in Brazil look promising.
We even use soil in a variety of industries: china dishes are made from soil and we use clay for beauty products. Plus, as mentioned above, soil acts as a powerful water filtration tool. Is there nothing healthy soil can’t do?
But what makes soil healthy in the first place?
Composition of healthy soil
The Penn State College of Agricultural Sciences
puts it well when talking about how healthy soil should function: “In order to grow our crops, we want the soil to hold water and nutrients like a sponge where they are readily available for plant roots to take them up, suppress pests and weeds that may attack our plants, sequester carbon from the atmosphere and clean the water that flows through it into rivers, lakes and aquifers.”
Organic matter is quite possibly the most important aspect of healthy soil. That includes plant and animal materials, soil microorganisms and products of these organisms and the decomposition process. Sources of organic matter include compost, manure and crop residues. Organic matter affects every aspect of the soil in ways that almost always help crop yield.
Healthy soil is also literally living soil. Penn State said one teaspoon of healthy soil off a farm can have 100 million to 1 billion bacteria, six to nine feet of fungal strands end-to-end, thousands of flagellates and amoeba, hundreds of ciliates, hundreds of nematodes, up to 100 insects and five-plus earthworms. All of these help break down, decompose and aerate organic matter into the nutrient rich mixture that puts food on the table.
Healthy soil should crumble but be moist as well. For instance, a healthy loam soil is 50 percent soil and 50 percent water and air.
With these complex requirements, it’s easy to muck up. So what are we doing wrong?
Threats to healthy soil
There are several major threats to healthy soil, all preventable:
This happens when soil has no air space in which to absorb water and air for plants. It’s caused by poor farming practices. Either the soil is not kept healthy with proper care (like adding enough organic matter) or the soil is trampled with equipment. If compaction gets bad enough, roots won’t even be able to penetrate the soil. The roots then can’t seek other nutrient-rich soil, and air and water cannot penetrate the soil as well to nourish the plants.
These are chemicals used in farming to increase crop yield. However, over time, it has backfired by disrupting the microorganisms in the soil. The result has been more harmful bacteria instead of beneficial bacteria.
As more forests are cleared for building and farmland, topsoil blows into waterways. Plants that replace trees cannot hold soil as well and erosion continues. Soil for growing food is getting dumped into rivers because trees are not in the way to stop it from happening. Trees that might have been there a day ago or could be easily replanted. Think about that for a minute.
Further, a scientist from the University of Delaware, Donald L. Sparks, stated in the journal Science
that soil erosion exceeds the rate of soil production. In the central United States, soil erosion is 10 times greater than the natural background rate of soil production. When the soil erodes, it washes away key nutrients that are never replaced.
Human-induced nutrient depletion:
This term is listed by the USDA
. Simply, this is the process of over-farming an area. Farmers can sometimes sap the nutrients out of the soil while growing crops and fail to put nutrients back into the soil. Causes include unbalanced fertilization, over-cultivation, flat-out not putting nutrients back into the soil and increased erosion by not managing the land properly.
Solutions in soil health
The solution to the problem lies in better agricultural education and sustainable land use. Sustainable agriculture will need to be the way of the future if we want to continue to actually grow food. For instance, the WWF
is working to make deforestation a thing of the past as much as possible, as well as promoting sustainable farming initiatives
like using less chemicals and keeping soil strengthened.