Relaciones fósforo-zinc en tres suelos ácidos de Costa Rica, 1: comportamiento en el suelo.

Abstract

The effects of high P and Zn applications and their interactions were studied in three acid (pH 5 .3-5.9 ) soils of Costa Rica. It was observed that as all three soils fixed P strongly, the obtained available P levels, were much smaller than expected based on retention curves. Adding the lowest P level resulted in a good growth of the test plants. An application to the soils resulted in increases in soluble Zn proportional to the added amounts. However, the observed increases were smaller than the expected ones, based on retention curves. The application of the Zn level needed for twice the estimated soluble amount (18 pg/g) which was 99-1 78 pglinl soil, resulted in only 10 to 15 pg/ml soil of extractable Zn. The treatments were generally reflected by the soil P/Zn rations and indicated low values (< 1.75) for the zero P treatment. The values for P treated pots varied between 1.97 and 10.05, considered normal.