This bulletin reports the results obtained from twenty years fertility investigations on Barnes sandy loam soil at Brookings, S. D. The three elements of plant food commonly applied in fertilizers-nitrogen, phosphorus, and potassium- were used singly and in all possible combinations on two crop rotations including corn, wheat, oats, barley, and red clover. Phosphorus used alone gave a greater increase in yield for all crops than any other treatment, averaging 32.08 per cent more than the yield from the untreated soil for the entire period. The average increase in yield for all crops, following the application of phosphorus, was 1979 pounds per acre per year. In round numbers, to make it easy to remember: Phosphorus has increased the yield of crops one ton per acre per year for twenty years.
soil fertility, soil fertility depletion, soil nutrients
South Dakota Experiment Station, South Dakota State College of Agriculture and Mechanical Arts
Hutton, J.G., "The Results of Twenty Years Complete Soil Fertility Tests Brookings, S. D." (1933). Research Bulletins of the South Dakota Agricultural Experiment Station (1887-2011). 280.