Capacidade máxima de adsorção de fósforo em latossolos da região do triângulo mineiro

Abstract

Phosphorus is essential for plant’s growth and healthy development, therefore the higher is its soil availability, the better it is for crops depending on increasing plant uptake. Adsorption retains phosphorus and makes it not available to crops. This present work was developed to determine the maximum phosphorus adsorption capacity for three oxisols classes: Eutroferric Red Latosol (LVef), Dystroferric Red Latosol (Lvdf) and Dystrophic Red Latosol (LVAd) at depths of 20 cm, and 1 meter, for each soil class in the state of Minas Gerais, in the Triangulo Mineiro mesoregion. The soil organic matter ranged from 8.59 to 32.93 gdm-3 with higher surface area concentration. The maximum capacity of P was estimated by Langmuir and Freundlich model and correlated with chemical attributes, Zero Charge Point (PCZ) and Remnant Phosphorus (P-Rem). Since these are arable regions that need an appropriate amount of phosphorus available for healthy plant growth. CMAP values ranged from 49.08 to 110.37 (mg/g), with a higher CMAP ratio for soil classes LVAd, which is the soil class that has the highest goethite concentration. Most of the P-rem values were rated as very low, and only LVef at a depth of 20 cm was rated low. It can be concluded that soils with a higher amount of organic matter have a lower maximum phosphorus adsorption capacity, which consequently will have a higher amount of phosphorus available to plants, and that all soil classes understudy had little amount of phosphorus available to crops, which causes farmers to use a large number of phosphate fertilizers, which pose great risks and damage to the environment.