Effect of boron fertilization of apple trees (Malus domestica Borkh.) on uptake and distribution of mineral elements

Abstract

The aim of this study was to examine effect of boron (B) fertilization of 'Šampion' apple trees (Malus domestica Borkh.) grafted on M.26 rootstock on uptake and distribution of mineral elements. The trees were planted at a distance of 4,0 x 2,5 m on sandy-loam soil with low hot-water extractable B content. The study was carried out in 1994-1996 in Dąbrowice Experimental Station located near Skierniewice. The following treatments were applied: (i) soil B application at a rate of 2g B tree<sup>-1</sup> as Bortrac fertilizer (16% B in form of boric acid); (ii) three times leaf B applications before full bloom at a rate of0,67g B tree' at the stage: green and pink bud and beginning of flowering; (iii) three times leaf B applications after bloom at a rate of0,67g B tree<sup>-1</sup>. First spraying was applied at petal fall and next two ones at 2-weeks interval; (iv) control-trees unfer tilized with B. The measurements included: soil chemical analysis (contents of available phosphorus (P) and boron (B) and exchange potassium (K), magnesium (Mg), and calcium (Ca) and plant analysis (concentrations of N,P,K,Mg,Ca and B in the spur leaves, the leaves from oneyear-old shoots and the apple flesh). It was shown that B fertilization had not effect on N uptake and its distribution within apple tree. It was found that soil B application stimulated P uptake which increased concentration of this element in the spur leaves, the leaves from current shoots and the apple flesh. Boron sprayings after bloom increased Ca uptake which rised Ca concentration in studied plant parts. Additionally, leaf B application after bloom reduced plant Mg uptake. As a result of B sprayings after bloom, K concentration was increased in the spur leaves and decreased in the apple flesh. Boron spraying before bloom was less effective in increasing this microelement in plant than leaf B applications after bloom and soil B application.