EFFECTS OF METHODS OF BORON APPLICATION ON LEAF TISSUE CONCENTRATION OF BORON AND CONTROL OF BROWN-HEART IN RUTABAGA

Abstract

Field experiments were carried out at five different locations in Prince Edward Island over a 3-yr period in an attempt to determine the effect of methods and rates of B application on the incidence of B deficiency (brown-heart) in rutabaga (Brassica napobrassica Mill. cv. York). Band applications of B resulted in greater tissue B concentrations than broadcast applications. Foliar sprays applied when roots began to swell (about 6 wk after seeding) resulted in lower tissue-B concentrations than those applied 4 wk after seeding but controlled brown-heart. Brown-heart was completely controlled by a band application of 1.12 kg B/ha, a broadcast application of 2.24 kg B/ha, or by two foliar sprays each at the rate of 1.12 kg B/ha. Leaf tissue B concentrations of 15–32, 33–38, and greater than 40 ppm were related to severe brown-heart, slight to moderate brown-heart, and complete control of brown-heart, respectively. An application of limestone, prior to seeding, generally reduced tissue B concentrations. Analysis of soil after harvest indicated B recoveries of 35–62% in treatments receiving broadcast B.