Muscle shoals. The production of nitrogen for plant food in peace and explosives in war is more and more important. It is one of the chief sustaining elements of life. It is estimated that soil exhaustion each year is represented by about 9,000,000 tons and replenishment by 5,450,000 tons. The deficit of 3,550,000 tons is reported to represent the impairment of 118,000,000 acres of farm lands each year.