soil fertility, Soils, organic matter, potash, phosphorus, nitrogen in soils
A successful and profitable agriculture must depend upon a sound and permanent system of soil management. A program of sound soil management is necessary to conserve our soil resources in order to insure present and future stability in agriculture. Changes in the soil which make it less suitable for crop production are gradual processes. Some of these changes are depletion of soil organic matter, appearance of nitrogen and other nutrient deficiencies, deterioration in soil structure, increased susceptibility of the soil to wind and water erosion, failure of crops to grow and mature properly, and lower crop yields. South Dakota soils arc still relatively fertile but many of these signs of soil depletion are beginning to appear. These changes or signs of soil depletion must be recognized and measures adopted to restore and maintain the productivity of the soil.
South Dakota State College of Agriculture and Mechanic Arts, Agricultural Experiment Station
Puhr, L. F. and Worzella, W. W., "Fertility Maintenance and Management of South Dakota Soils" (1947). Agricultural Experiment Station Circulars. 65.