Summery of Bulletin
1. The average value of the crops produced at Brookings for five years was 31.1 per cent greater where phosphorus alone was applied than where no phosphorus was applied. Page 256.
2. The average value of the crops produced at Brookings for five years was greater where phosphorus alone was applied than where any other element of plaint food was applied or where any combination of elements of plant food was applied. Page 255.
3. If the fact that more than one half of the phosphorus applied yet remains in the soil is taken into consideration, the application of phosphorus even in an expensive form seems to be commercially profitable. Page 258.
4. Phosphorus is the limiting element of plant food in crop production in the soil at Brookings. Page 250.
5. It does not pay to buy nitrogen. Page 257.
6. Grow legumes to add nitrogen to the soil Page 251.
7. It does not pay to buy potassium. Page 257
8. The application of plant food cannot take the place of rainfall. Page 260.
Note -- If plant food can be applied to some soils at a profit to the farmer and to other soils at a loss, a soil and crop survey to enable the state to ascertain the facts will add millions of dollars to the state's wealth and point the way to permanent, profitable agriculture.
Rainfall data on page 263.
soil fertility, plant food, crop production
South Dakota Experiment Station, South Dakota State College of Agriculture and Mechanic Arts
Hutton, J.G., "A Report of Progress in Soil Fertility Investigations" (1913). Agricultural Experiment Station Bulletins. 145.