Abstract: Nitrogen compounds are a source of soil acidity. In addition nitrates are a major factor in the leaching of other nutrient salts from soils. These salts are then replaced by the available hydrogen ions, rendering the soil even more acidic. Besides supplying nutrients, a desirable fertilizer should offset changes in soil acidity brought about by nitrification. Calcium carbonate accomplishes this. Unfortunately it has not been possible commercially to include calcium carbonate in a fertilizer. If CaCO.sub.3 particles are ground too large they do not dissolve along with the agricultural fertilizer nutrients. If CaO.sub.3 is pulverized to a state necessary for dissolution, because of its hygroscopic properties, it hardens or cakes. It is not sufficiently stable in admixture with the other fertilizer materials for commercial distribution. Herein a fertilizer is provided which improves the condition of the soil, and stimulates microbial activity in the soil.