FAQ #3 - How the organic materials work
How does the organic program work?
How do the plants get fertilized from protein?
Normal healthy soil is teeming with 25,000 to 45,000 different species of microbes including bacteria, fungi, and others. When the microbes are well fed, they produce compounds that feed the plants, regulate their growth, stimulate their defense functions, and actually kill off pathogenic microbes and pests. The process has been in development by Mother Nature for well over 200 million years. The process is pretty nearly perfect.
The soil microbes need sugars and proteins to live. The sugars they get from the plant roots. Proteins they receive from dead plants and animals that fall onto the soil. My idea of an organic turf program is one that provides the protein in a way that doesn’t smell bad or carry a stigma of using dead animals.
In nature, animals and plants die. Those dead bodies and plants fall to the ground and their protein becomes food for many animals both above and below ground. Protein is a combination of molecules that always include plenty of nitrogen. When the thousands of species of living soil microbes digest the protein, the nitrogen is eventually converted into nature’s own perfect plant food. The plant food is exchanged between the microbes and the plants in return for the sugars provided by the plants. The process is very complicated and a new term has been coined to describe it. It is called the Soil Food Web. That term indicates that the microbes are not in a food chain as we know it but in an interconnected web of food chains that all exchange proteins and wastes with each other.
Many of the soil microbes, as well as insects and earthworms, can digest human and animal pathogens and convert them into plant food, too. This is the process that happens inside a compost pile and also in the soil. At the end of the digestion process, what is left is various organic and inorganic compounds known by different names but which includes a material loosely called humus, an inert, dark brown, material which stores plant foods and other chemicals in the soil. Humus is what gives rich black earth the dark color.
So the secret of the soil is that the “organic matter” that really matters is not the dead leaves that fall onto it, but the living microbes that eat the dead leaves.
We can simulate the dead animal protein by using ground up dead animal meal as a “fertilizer” on the lawns. Unfortunately dead animal meals stink, so instead the organic community uses vegetable sources of protein such as corn meal, soybean meal, cottonseed meal, coffee grounds, canola meal, milo meal, corn GLUTEN meal, or whatever is inexpensive in your neighborhood. These meals usually come in plain, brown, 50-pound bags marked, “feed.”
For homeowners, 50-pound bags are plenty big to heft around, especially when compared to the 15 pound bags of Scotts they might be used to carrying. But for the professionals, if you’re doing acreage, you may want to find a place that can deliver material in 1,000-pound lots. It may be bagged or not, depending on what you ask for.
Protein is a source of nitrogen. Luckily grass is a nitrogen hog.
The other food that soil microbes need in abundance is sugar. This is where Mother Nature uses the plants to provide. Through photosynthesis, plants manufacture excess amounts of sugars for their own use. The rest is meant to be delivered to, and used by, the microbes under the soil.
Sugars and nitrogen foods must be in balance in the soil for the microbes to thrive. If the sugar to nitrogen balance gets out of balance, you can start to have problems with the garden. Plants can die from too much nitrogen. You already knew that over applying fertilizer is hazardous to plants. Fortunately, plants cannot get too much nitrogen from vegetable sources of protein. They can; however, get too much from animal sources. Blood meal and urea are two examples where plants can die from the ability of these two protein sources to release nitrogen in a hurry. The nitrogen is more readily available in these animal sources. I will not be recommending any hot animal sources of nitrogen. But it is also possible that too much sugar can cause a problem. So where sugar is suggested to rebalance the nitrogen/sugar ratio, use some care and don’t apply sugar outside the area needing treatment.
Moderator, Organic Lawn Care Forum
San Antonio, TX