No abstract

Fertility experiments have been conducted with field corn on Everglades Peaty Muck soils in order to determine the required fertilizer program with respect to P2O5 and K2O. Four experiments have been conducted involving potash, phosphate experiments laid out in randomized block designs and nitrogen, potash, phosphate experiments laid out in 3 × 3 × 3 factorial designs. Soils tests were used to determine the P2O5 and K2O levels in the soil and tissue tests were conducted to measure the uptake of these nutrients from the soils. These data have been correlated with yields in order to furnish the necessary information on which to base fertilizer recommendations from the results of soil or tissue tests. The corn showed yield responses to increasing levels of potash in the soil up to values as high as approximately 70 pounds potassium per acre as determined by the soil tests. The yields ranged from 26 bushels per acre at the lowest K2O levels to 63 bushels at the level of maximum response which produced plants that gave stem tissue tests averaging approximately 5.00% potassium, moisture free basis. Potash deficient corn gave tissue tests as low as 2.72% potassium. Yield responses to applications of superphosphate were obtained up to levels of approximately 8 pounds per acre of water soluble phosphorus as determined by soil tests. Plants showing no phosphate deficiencies gave stem tissue test values in excess of 0.10% of the element, moisture free basis. The assimilation of P2O5 was apparently reduced by higher levels of K2O in the soil and that of K2O was reduced slightly by higher levels of P2O5. The experiments indicate that fertilizer recommendations for field corn on organic soils may be intelligently made on the basis of soil tests which have been previously correlated with growth and yield response.