Salinidade da água de irrigação na produção de fitomassa e acumulação de nutrientes no cajueiro anão precoce.

Abstract

The objective of the present work was to evaluate the effects of different irrigation water salinity levels, during the fructification phase, of the CCP76 dwarf precocious cashew nut clone (Annacardium occidentale L.) on the phytomass production and on the levels of nitrogen, phosphorus, potassium, chloride and sodium of the roots, rootstocks, graft, branches and leaves. The study was carried out under greenhouse conditions testing 5 irrigation water salinity levels – ECw: 0.8; 1.6; 2.4; 3.2 and 4.0 dS m-1 to 25oC on three phases of the phonological cycle of the flowering to the beginning of the fructification and from the beginning to the end of the fructification. The experimental design used was blocks at random with six replicates on a factorial scheme (4 x 3) +1, totalizing 13 treatments and 78 parcels. Each experimental unity was composed by a single plant. It was verified that the accumulation of dry matter in all the analyzed parts of the plant decreased with the irrigation water salinity. Of the studied elements, the nitrogen was the only inhibited by the irrigation water salinity in all the parts of the plant. The increase of the water salinity had a highly significant effect on the phosphorus and potassium content of the grafts, branches and leaves. With the exception of the leaves, it was observed an increase of the chloride and sodium levels on the with the salinity of the irrigation water.