Fertilizer form, particle size, solubility, and potential uptake are extremely important in fertility programs for gardening. Organic gardeners place great emphasis on using natural minerals and organic fertilizers rather than manufactured ones in order to build their soil. If you use organic materials as all or part of your fertilization program, this bulletin will help you calculate the proper amount to use from the guidelines recommended by a soil test. Organic Matter Organic matter is the varied array of carbon-containing compounds in the soil. Organic matter is created by plants, microbes and other organisms that live in the soil.
Organic matter provides energy for biological activity.
Many of the nutrients used by plants are held in organic matter until the organisms decompose the materials and release them for the plants' use. Organic matter also attracts and holds plant nutrients in an available state, reducing the amount of nutrients lost through leaching. It improves soil structure, so that air reaches plant roots and the soil retains moisture. The organic matter and the organisms that feed on it are central to the nutrient cycle. The other 35 pounds of material in the bag is filler or carrier.