Comparison between fertilization with potassium chloride and two types of potassium rocks in the growth of Eucalyptus urophylla

Abstract

The scarcity of Brazilian rocks rich in potassium and solubility that make the soil element available to plants justifies the dependence on the import of potassium fertilizers. In this sense, the present work had as objective to compare the performance of two types of rocks in natura (biotite schist and phonolite) in comparison to the fertilization with KCl in the growth of Eucalyptus urophylla. The treatments used were: T₁ = control without K; T₂ = 60 kg of K₂O per ha as KCl; T₃ = 120 kg  K₂O per ha as KCl; T₄ = 240 kg of K₂O per ha as KCl; T₅ = 120 kg of K₂O per ha as phonolite; T₆ = 120 kg of K₂O per ha as biotite schist; T₇ = 60 kg of K₂O (KCl) per ha + 60 kg of K₂O per ha (phonolite); T₈ = 60 kg of K₂O (KCl) per ha + 60 kg of K₂O per ha (biotite schist). It was observed after six years of planting that the diameter at breast height of plants under T₃ did not differ statistically from T₅.