Full text
| |
| Author(s): |
Thiago de Souza Celestrino
Total Authors: 1
|
| Document type: | Doctoral Thesis |
| Press: | Ilha Solteira. 2018-02-16. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Engenharia. Ilha Solteira |
| Defense date: | 2017-12-21 |
| Advisor: | Salatiér Buzetti |
| Abstract | |
Cerrado soils have low organic matter content, and this being the main primary source of boron (B), it is necessary to supply this element through fertilization. Therefore, in commercial eucalyptus plantations, it is common to fertilize in the planting groove and even via the foliar, during the implantation phase of the crop. Therefore, it is important to verify if the application of B carried out initially is sufficient to meet the crop requirements during the cycle, or if it is necessary to reapply the element under cover. The objective of this work was to compare the residual effect of the B sources applied to the planting groove, as well as the foliar application of the element and the reapplication of B in cover in the eucalyptus crop (clone I144), considering the high index of bifurcation in the treatments that did not receive the application of B. The experiment was conducted at Fazenda Renascença, located in the municipality of Três Lagoas/MS. The experimental design was randomized blocks, with five replications, in a factorial scheme, where the plots were subdivided, making a 3 x 2 x 2, being the first factor: 0 kg ha-1 of B; 1 kg ha-1 of B using borogran fertilizer (low solubility, 10% B), manually applied in continuous fillet in the planting groove; 1 kg ha-1 of B using boric acid fertilizer (high solubility, 17% B), manually applied in continuous fillet in the planting groove. Factorial 2 refers to the application or not of B via foliage. Two foliar applications of B were carried out until the first year of culture. In each application, 0,5% boric acid was used in the syrup with a volume of 250 L ha-1. The last factor 2, refers to the subplots that received or not the reapplication of B at 34 and 46 months after planting, in the crown projection, using the boric acid fertilizer at the dose of 1 kg ha-1 of B in each application. For the application of 1 kg ha-1 of B in the plantation, there is a need for reapplication of the covering element, positively influencing the soil element content, nutritional status of the crop, wood productivity, soil B transfer and soil concentration. element not leafed. The reapplications of B also promoted the greater accumulation of the element in the trunk of wood, thus reducing the efficiency of use of B in the production of wood. Although there was a greater residual effect of B in the soil due to borogran application, the sources of B behaved similarly to the measurements of wood productivity, leaf concentration, stem quality and soil transfer. It should be noted that even though a dose considered low (1 kg ha-1 of B), its application, as well as the foliar applications of B, reduced the percentage of bifurcation of the trees. There is a higher concentration of B in lower leaves of the crown when compared to the upper leaves, indicating, therefore, the low mobility of the element in the phloem. The basic wood density and the accumulation of B in the fractions (branches and leaves) were not influenced by the residual effect of the boron sources, as well as the foliar applications and reapplication of the cover element. (AU) | |
| FAPESP's process: | 14/03387-6 - Residual effect and reapplication of boron in Eucalipto crop clone I144 |
| Grantee: | Thiago de Souza Celestrino |
| Support Opportunities: | Scholarships in Brazil - Doctorate |