A positive growth response to NaCl applications in Eucalyptus plantations established on K-deficient soils

Contrasting responses of Eucalyptus trees to K fertilizer applications have been reported on soils with low K contents. A complete randomized block experiment was set up in Brazil to test the hypothesis that large atmospheric deposits of NaCl in coastal regions might lead to a partial substitution of K by Na in Eucalyptus physiology and enhance tree growth. Treatments with application of 1.5, 3.0, 4.5 kmol K ha⁻¹ (K_1.5, K_3.0, K_4.5, respectively) as KCl, 3.0 kmol K ha⁻¹ applied as K₂SO₄, 3.0 kmol Na ha⁻¹ (Na_3.0) as NaCl commercialized for cattle feeding, and a mixture of 1.5 kmol K + 1.5 kmol Na ha⁻¹ (K_1.5 + Na_1.5) were compared to a control treatment (C) with no K and Na applications. All the plots were fertilized with large amounts of the other nutrients.