Soil structure has an important influence on soil erosion, water intake, and crop growth. A dispersed or compact soil has a low infiltration rate. A stable, granulated soil will permit rapid water intake, drainage, aeration, and beneficial microbial activity; crops grown in it will respond well to favorable moisture, fertility, and good cultural practices. Among the most effective aids to good management in maintaining or improving granulation are microorganisms and their decomposition products. Growing plants and microorganisms constitute the living phase of the soil. In it are living and non-living bacteria, viruses, phages, fungi, algae, protozoa, earthworms, nematodes, and insects. These organisms have numerous enzymatic systems which are capable of producing available nutrients for the growing plants by breaking down some of the many organic compounds in the soil. Physically, a good mineral soil is made up of about five per cent organic and 95 per cent inorganic materials by weight. The influence that the organic matter in most soils exerts is out of proportion to its weight and is more directly related to the volume it occupies. This organic fraction of the soil is made up of plant and animal remains in all stages of decomposition. Chemically it is composed of sugars, starches, celluloses, proteins, lignins, vitamins, pigments, fats, oils, and myriads of compounds in all sorts of configurations and combinations. The mineral portion of the soil is made up of sand, silt and clay mixture in different combinations to make specifically a clay, silt loam, or soil of some other texture. Chemical elements of the inorganic fraction are composed largely of oxides, silicates, and phosphates of calcium, potassium, magnesium, etc., and the number of compounds ranges into the hundreds.