Behavior of the residuality of phosphorus and potassium in a Vertisol.

Abstract

Studying the behavior of the residuality of the phosphorus and the assimilable potassium, applied to the beginning of the cycle of plantation of the cane of sugar in a Vertisol. The obtained laboratory results of the soil samples were evaluated taken annually, during the period 2004-2007, in the phosphorus experiments and potassium, located in the EPICA of Holguin, Cuba. It was determined the phosphorus and the assimilable potassium by the method of Oniani. It was carried out an analysis of variance bifactorial and the tests of Fisher and Tukey with the software ESTATISTICA 8. The contents of assimilable applied phosphorus every 5 years diminish gradually in the period studied in OMPr4, this decrease is more remarkable where it was fertilized with 125 kg.ha-1. In the case of the assimilable potassium, in OMKr4, the same one fluctuates in all the studied treatments.