Doses de boro aplicadas via foliar, sua absorção e transporte na cana-de-açúcar

Abstract

Sugarcane (Saccharum spp.) is a crop of great socioeconomic importance in Brazil, and its productivity is scaled by several factors, especially soil fertility conditions. The Brazilian Savanna has a high degree of weathering, low natural fertility and major limitations for agricultural production, under these conditions, the use of boron-based foliar fertilizers is an alternative to supply micronutrients for cultivated crops. In agriculture, Boron polyol is a fertilizer capable of mimicking biomolecules that few plant species elaborate to transport the element via phloem. Thus, the objective of the present work was to evaluate doses, absorption and transport of boron (B) applied via foliar in the sugarcane crop under controlled conditions in the greenhouse. The experiment was conducted in a greenhouse belonging to the Institute of Agricultural Sciences of the Federal University of Uberlândia-MG, during the period from 02/19/2021 to 08/05/2021. The statistical design adopted was completely randomized (DIC), with 7 treatments and 4 replications, distributed in 28 PVC pots with a capacity of 40 dm-3 of soil. The treatments of B Polyol, Boric Acid solution, and Control were evaluated; with doses respectively of 50, 100 and 150 g ha-1 of B Polyol and 100, 200 and 300 g ha-1 of boric acid solution. To avoid contamination, the pots with MPB were protected with plastic film. For the analysis of macro and micronutrient contents, all leaves were collected and properly prepared for analysis. The treatment means were submitted to analysis of variance using the SISVAR 5.3 program and compared by Tukeye Scott-Knott tests. Regression analysis was also performed using the SISVAR 5.3 and SigmaPlot 11.3 programs. The results showed higher levels of B in the old leaves that had received foliar spray, while the new leaves, which developed after application, did not show statistical difference. No differences were observed in N contents in young and old leaves after application of different doses of B Polyol and boric acid. The highest absorption and translocation of B were obtained with the application of the two highest doses of B Polyol (100 and 150g ha-1 of B). When applied at doses of 50 and 100g ha-1 of B, the application of B Polyol resulted in values of fresh matter and shoot dry matter in sugarcane plants higher than those obtained with the application of 200g ha-1 of B via boric acid.