Compost as a Soil Amendment

Kith talking about compost @ last night's class

It’s not that the soil in our backyards is infertile, it’s just that the top soil has usually been scraped away (to make for a solid surface on which to construct the houses we live in), leaving us with a sub-soil consisting of mostly clay, to work with. While the mineral content of clay soils is high, the porosity of the soil and the drainage is lacking... So the question is, how do we improve our soils?

By adding compost to new plantings and by adding thin layers of compost as a top-dressing or mulch we begin to restore a balanced and healthy system to our soils. The cycling of nutrients is actually taken care of by microorganisms (bacteria, fungus, protozoa, nematodes, etc.) that feed on compost. Any nutrients that were retained by the once living plant are locked up in the decaying organic matter (compost). Bacteria and fungus are able to digest this material and "hold " the nutrients in their tiny bodies. Protozoa, nematodes, microarthropods, worms, and other soil organisms will, in turn, eat the smaller bacteria and fungus and excrete the nutrients they don't retain as a waste product. This "waste" is what plants feeds on... nitrogen in a plant available form! Large populations of microorganisms means more nutrients for your plants!Nature has perfected this system of nutrient cycling and it should be our goal as gardeners to restore this balance in our own backyards. Compost applications won't improve our soils overnight, but within a few years there will be a marked decrease in the amount of fertilizer and pesticides required to keep our plants healthy and happy.

Using compost to amend our soils is beneficial in more ways than one.... In addition to microorganisms unlocking nutrients in the soil, these organisms also help to create improved soil structure. How can millions of microscopic animals improve the structure of your soil? ...Fungal strands, worms, insects, etc. are constantly moving through the soil. This helps to create passageways through which air and water flow, improving the porosity of the soil. At the same time, mucus secreted by worms and the "bio-slime" in which bacteria live help to bind soil particles together.

Another way that improving your soil directly benefits your plants is disease suppression. Mychorrhyzal fungi, living in and around plant roots, will actually attack and kill root-feeding predators right at the root zone. They can also create a physical barrier around a plant’s roots, blocking the bad guys out. Additionally, bacteria and fungus can both alter the ph of the soil resulting in different forms of nitrogen available to different types of plants. When your plant gets the form of nitrogen that it requires, it is able to grow stronger and healthier, allowing it to fend off certain diseases and insects. In some cases microorganisms are even known to dispense vitamins and hormones useful to plants...

In summary, the application of compost to your garden soils will help to naturally create nutrients for your plants, improve soil structure and increase drainage, and introduce organisms that help our plants fight off diseases and insects. Whether you decide to make your own or buy compost from the garden center, you will be doing yourself and your plants a huge favor by amending your soil... and you'll only have to use chemical fertilizers and pesticides in emergency situations. Save money in the long run and do the environment a favor... Compost!

I found this link, Digital Learning Centerfor Microbial Ecology which is an informational website for both children and adults. Check it out. It's a fun way to learn more about the microbiology that directly benefits you and your plants!