Compost applied to soil breaks down further into humus. Soil with adequate humus will have better water absorption, water drainage, sufficient water retention, more nutrients, and better crumb structure than soil without humus.
For healthy soil, it should continually be replenished with new applications of compost because organic matter is consumed by soil life. Without organic matter, your soil will have few living creatures and scarce plant growth. Humus is required for healthy soil.
Soil tests can be performed by many soil laboratories to provide you with feedback on levels of various nutrients and to give you an idea of how much organic matter is currently in your soil.
To find a reputable lab, call your local cooperative extension service (in the U.S.), agricultural university, or ask for suggestions from your local nursery. They will tell you the proper way to collect soil samples; it isn’t difficult at all. Soil testing can be very enlightening.
For instance, years ago I had my first soil tests performed. I found out that I had enough of every single nutrient in my soil except Nitrogen. The bad news was that I had so little Nitrogen that what was there, if anything, didn’t even register.
In my soil test results, there was a big, fat zero next to the word “Nitrogen.” I thought that there had to be some mistake, so I called a friend of mine who is a soil scientist. He told me that that is exactly the results he would have expected in my area. There is a general shortage of Nitrogen here.
He told me that it is unfortunate that more people don’t have soil testing performed. People often make sure they are buying balanced N-P-K fertilizers. But if their soil is out of balance to begin with, like mine was, the balanced fertilizer maintains that out-of-balance state because it raises both the deficient and non-deficient nutrients. So I went in search of 100 percent Nitrogen organically-safe fertilizer. It wasn’t easy, but I found some. It made a huge difference.
It’s great to know where you start off, but as you make adjustments to your soil, it will change. Certainly it will change as you begin to add compost, so re-test every year (or at least every few years).
I realized that fighting soil that was naturally low in Nitrogen wasn’t a great plan, so I built raised beds in my garden. My intention is to have soil tests performed every year, but in reality I usually end up doing it every few years. Just make sure you get updated reports so you are taking action with current information.
It is difficult to beat laboratory soil testing for actionable information. However, a quick and dirty test for adequate organic matter in soil is to count the earthworms you find. Here’s the procedure:
- Mark off a 1-foot square of soil.
- Start digging this patch carefully to a depth of about six inches, counting earthworms as you go.
- When you count 10 earthworms, you can stop digging. Congratulations! You have adequate organic matter in your soil. That doesn’t mean you shouldn’t add more. Organic matter is consumed constantly, so more is better.
- If you dig the entire square foot of soil and don’t find at least 10 earthworms, your soil needs a higher proportion of organic matter. So start composting!
Other factors that can reduce the earthworm population are soil compaction, poor drainage, drought, and chemicals.
Earthworms are a good indicator of soil life. If the earthworms aren’t happy with soil, it’s unlikely that you have robust soil life.
I always pay attention to earthworms.
Whenever I use anything new on my soil, such as a new brand of mulch, I put a patch down and come back in 2 or 3 days to check if the earthworms are still there. If they aren’t, I don’t put the rest of the product down even if the label says organic. Earthworms never lie!
Mary Tynes, Master Composter, www.mastercomposter.com
Image Credit: http://www.flickr.com/photos/suavehouse113/536902862/