Residual effect and reapplication of boron in Eucalipto crop clone I144

Abstract

Cerrado soils generally have low levels of organic matter, which is the main primary source of boron (B), which makes limiting the cultivation of high demand crop, such as eucalyptus. Therefore, in commercial plantations, it is common to fertilization at planting and foliar application of this element in the deployment phase of the crop. Therefore, it is important to verify that the application of B initially held is sufficient to meet the demands of crop throughout the cycle, or if it is necessary to reapply the element in coverage. The objective is to compare the residual effect of B sources at planting, as well as the foliar application of the element, and reapplication of B in covering on cultivation of eucalyptus (clone I144), due to the high level of forked percentage of plants on treatments without application do B. The experiment is being conducted at Renaissance Farm, agricultural fund managed by Cargill Agricola S / A, located in Três Lagoas / MS with latitude 20º 34' S and longitude 51º 50' W and altitude of approximately 305 m. The experimental design is a randomized complete block, with 5 replications, in a factorial scheme. The plots will be split in an arrangement 3 x 2 x 2, where the first factor is: 0 kg ha-1 B; 1 kg ha-1 B using borogran fertilizer (low solubility, 10 % B), manually applied in a continuous line at planting; 1 kg ha-1 B using boric acid fertilizer (high solubility, 17 % B), applied in a continuous line at planting. The second factor is with or without application of foliar B. Two foliar applications of B, at four and ten months after planting were performed. Boric acid was used in each application, to 0.5 % in the mixture with a volume of 250 L ha-1. The last factor 2, refers to subplots that will receive or not reapplying B at different times. The B applications will be held, the first in the rainy season (November/2014) and the other in the dry season (March/2015), at 0.5 kg ha-1 B each application, being manually applied to the projection crown of the tree, at the distance of 50 cm from the plant. Two other B applications in coverage will be repeated in the subsequent 2015/16 year, using the same dose and time of application. The following evaluations will be conducted: Plant height, diameter at breast height, volume of wood with bark, forked percentage of plants, soil nutrient content, nutrient concentration in the leaves, concentration of B in leaf litter and basic wood density. (AU)