Assesment of Phosphorous Recovery Efficiency from Local and Concentrated Souced Ferilizer by Eucalypts {Eucalyptus Grandis}

Attempts were made to validate the recovery efficiency of phosphate rocks {Araxa and the concentrated Arafertil} in planting Eucalyptus grandis in relation to triple superphosphate. Two experiments were carried out at Carbonita {longitude 17 0 44 1 and latitude 430141} and Bom Despacho { longitude 190351 and latitude450171 } in the Cerrado area of Minas Gerais State, Brazil. Application of the natural phosphate Araxa {P2o5 24% and Ca 25%} was at 500, 1000, 2000, and 4000kg/ha and Arafertil {33% -P2o5 and 33% Ca} was at 1000kg/ha. Also, triple superphosphate {45% -P2o5 and 13% Ca } was applied at 250, 500, 1000 and 2000kg/ha.

It was observed that, in both areas, the application of the natural sources (Araxa and Arafertil) gave similar results in volume, height , and production of dry matter. This is possibly due to best distribution of rains during the assessment period and, probably, limitation of potassium in the soil. The major plant P utilization estimate at Carbonita indicated minor availability of phosphorous in soils with reflection to critical concentration of nutrients in the above-ground portion of the plants. Plant phosphorous recovery from Araxa rock was similar to that from triple superphosphate, varying between 3-11 %.