Adubação potássica aplicada na axila foliar e no solo em coqueiro anão verde1

Abstract

The influence of doses of KCl applied via soil and via leaf axil on the leaf nutrient concentration in green dwarf coconut tree (Cocos nucifera L.) was evaluated. The experiment was conducted in a commercial orchard in Campos dos Goytacazes, Brazil, in a Typic Quartzipsamments, from May 31, 2007 to May 31, 2008, using a randomized complete block design with five treatments and sixteen replicates. Treatments consisted of two application modes (on soil and on the axil of the leaf number nine) and two levels of KCl (1666 and 3333 g of KCl per plant, per year) level 1 and 2 for soil and (833 and 1666 g per plant, per year) level 1 and 2 in for plant axil, with three month interval applications), besides a control, without KCl. Leaf samples were collected before the first fertilization and three months after each fertilization. Application of KCl increased leaf concentrations of K and Cl and reduced Mg concentration in plant tissue. Leaf concentrations of N; P; Ca; S; B; Cu; Fe; Mn and Zn were not influenced by the treatments. The application of foliar potassium allows greater absorption of this nutrient by plants. The foliar application minimizes losses and can reduce the quantity of potassium fertilizer applied.