It might be hard to believe, but the soils in our gardens, lawns and farms are more than just dirt. Soils are living, breathing communities, and it is important we make sure our soils are healthy. This is especially important if we expect to eat deliciously sweet corn or juicy tomatoes. A few weeks ago, I went to my first farmer meeting at the Cuddeback Farm near Skaneateles. Many of the farmers at this meeting spoke about what healthy soils mean to them. In many cases, healthy soils translate to healthy crops. This concept applies to our household gardens, as well. If our soils are not healthy, we should not expect to harvest tasty and plentiful vegetables. However, before we can begin to improve the health of our soil, we need to understand a few things. What is soil? What does it mean for a soil to be healthy?
Soils are made up of four main parts: mineral solids, air, water and organic matter. Mineral solids are small pieces of stone, sand, silt or clay that have been eroded from or broken off of larger rocks. For example, if there are a lot of sandstone rocks nearby, you would expect to see quite a few sand grains in the soil. Air and water are also important because living organisms in the soil need both to survive. Organic matter is just another name for any material that came from something living. I should mention here that organic matter is different from mineral solids, which came from nonliving materials. Many people mix compost or fallen leaves into their garden soils. These are both very good examples of organic matter. However, organic matter can also include living things such as worms, microscopic organisms or plant roots.
Now we have a better understanding of soil, let’s talk about what makes a soil healthy. The Cornell University Soil Health Test focuses on three main soil properties: physical, chemical and biological. By physical properties, the test tries to answer questions such as: “How well does your soil stick together when it gets wet?” “How much water can your soil hold for plants to use?” and “How compacted or packed down is your soil at the surface and at deeper depths?” Important questions concerning chemical properties might include: “What is the pH of your soil?” “What nutrients are available to your plant?” and “Are there any toxic elements in your soil like lead, arsenic, etc.?” Finally, some key questions about biological soil properties might be: “How much organic matter and nitrogen does your soil have and how much is available or ‘active’ to plants and soil organisms?” and “Do the roots in your soil look healthy?” A soil health test from Cornell will give your soil a grade for all of these different properties. A green report card means that your soil looks healthy. Yellow means you should slow down and focus on this issue before it becomes a problem. Red means you need to stop and figure out (with the help of a soil manager) how to overcome this problem. As an example, if you received a red grade for soil organic matter, you may decide to either add compost or work fallen leaves into your soil.
Knowing what a soil is and what steps we can take to improve our soil health are great first steps to foster a healthy soil community. As I said before, soil is more than just dirt. It is alive and full of microbes that do a number of beneficial things. Soil microbes help decompose or break down organic matter and release nutrients into the soil that plants can easily take up. Several of the farmers at the farmer meeting I spoke about emphasized soil microbes "acting like glue" to give the soil more strength and structure. Finally, a healthy soil is full of microbes that can help suppress pests and disease, preventing organisms from harming our plants. As a result, a healthy soil community translates to stronger plants that are more resistant to pests and disease. The next time you look at the soil in your field or garden, consider what the soil community might be like. Maybe even take a peak — you might be surprised by what you find.
For more information about the Cornell Soil Health Test, visit soilhealth.cals.cornell.edu.
Source: Cornell Soil Health Assessment Training Manual