Although farming communities long understood the need to provide soil with the nutrients that plants most needed for their successful growth and fertilizers of various forms had long been used, there was an increased use of chemical fertilizers in the late 1940s. This was a direct result of the conclusion of World War II. The US government needed to find a use for the surplus ammonium nitrate left over from the making of munitions for the war. The Department of Agriculture realized that the chemical could be used as a fertilizer, providing plants with an excellent source of the nitrogen needed for their growth.