Doses e formas de aplicação de selênio na cultura da soja

Abstract

, Alexandre Martins Abdão dos Passos 6 RESUMOObjetivou-se, nesse trabalho, determinar os efeitos de doses e formas de aplicação de selênio na forma de selenito de sódio na produtividade e características agronômicas da soja [Glycine max (L) Merrill]. Utilizou-se um delineamento experimental em blocos ao acaso, com um esquema fatorial de 4x3 +(1) compreendendo 4 doses de selênio (0,5; 1,0; 1,5; 2,0kg ha -1 ), três formas de aplicação (solo, foliar e solo + foliar) mais uma testemunha sem adubação, com três repetições. No tratamento solo + foliar aplicou-se a metade de cada dose isolada. A aplicação do selênio no solo foi feita na semeadura em mistura com os macronutrientes, e a aplicação foliar foi realizada no estágio V8 da cultura. As parcelas foram constituídas de 4 linhas com 5 metros de comprimento, espaçadas em 50 centímetros, com uma densidade de 12 plantas por metro linear. A adubação com selenito de sódio via foliar, independentemente das doses, afeta altura da planta, altura da inserção do primeiro legume e número de sementes por legume, promovendo um efeito fitotóxico na planta, chegando a reduzir em até 21% a produtividade. O número médio de legumes por planta e a massa de 100 sementes não sofreram efeitos da adubação com selênio. Termos para indexação:Glycine max, selênito de sódio, fitotoxidez, produtividade de grãos. ABSTRACTThe aim of this work was to determine the effects of doses and forms of selenium applications in the form of sodium selenide on the productivity and agronomic characteristics of the soybean [Glycine max (L) Merrill]. An experimental design in randomized blocks was used with a factorial outline of 4x3 (+1), four selenium doses (0.5, 1.0, 1.5, and 2.0 kg.ha -1 ), three application forms (soil, foliar and soil + foliar), and a control, with three replications. In the treatment soil + foliar, half of each dose isolated was applied. The application of selenium to the soil was made in the planting process and the application to the leaves was accomplished in the V8 stage of the culture. The parcels were composed of four lines with five meters in length, spaced 50 centimeters from each other, with a density of 12 plants for each linear meter. The fertilization, with sodium selenide via leaves, independently of the doses, affected the characteristics height of the first pod insertion, height of the plant, and number of seeds in the pods, due to a phytotoxic effect, decreasing the productivity in 21%. The average number of pods per plant and the average weight of 100 seeds were not affected by the fertilization with selenium.

Brachiaria enrichment with selenium-coated urea

“…A potential explanation is due to low Se bioavailability and concentration in the soil. Selenium fertilization in these areas could improve concentration of Se in the soil and consequently improving the metabolism and quality of plants (RIOS et al, 2010).There are complex paths associated with enrichment of Se by fertilization, which include the existence of different Se forms, difficulties to reach desirable levels in leaves or edible parts of plants (LI et al, 2008) and at the same time take care to avoid yield damages and/or toxicity (MARTINEZ et al, 2009). However, there are cereals and forages that are able to uptake high levels of Se and do not develop phytotoxicity (OLIVEIRA et al, 2007) that could result in animal intoxication, since requirement of Se by cattle in a dry matter base is between 0.1 to 0.3mg kg -1 (NRC, 2001).…”