Título en español.

A series of fertilizer experiments with tobacco revealed the following highlights as to the influence of the fertilizer on yields of barn-cured tobacco per acre: 1. On a Juncos clay there was a significant response to 50 pounds of N and of P2O5 per acre, respectively. Potash did not influence yields. 2. A single fertilizer application at time of planting gave yields of tobacco equal to those where the fertilizer was applied 10 days after planting or was split into two applications. 3. No source of nitrogen, either inorganic, organic, or mixtures of both, proved superior to ammonium sulfate for tobacco. 4. No source of potassium, either inorganic, organic, or mixtures, increased yields of tobacco. 5. The use of 1 ton of lime increased yields significantly on a Juncos clay, but not on a Caguas or Mabí clay. 6. The use of gypsum alone, or in combination with lime, failed to increase yields. 7. Magnesium, boron, and complete minor-element mixtures failed to increase tobacco yields. 8. The amount of rainfall during the growth of the tobacco crop influenced both yields in general and the response of the tobacco to the fertilizer applied. Higher yields and fertilizer responses were obtained with increasing rainfall.