Efeito da competição de plantas daninhas e de herbicidas na morfofisiologia da erva-mate (llex paraguariensis)

• Ano de defesa: 2017
• Autor(a) principal: David, Felipe Adelio De
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal da Fronteira Sul; Brasil; Campus Erechim; Programa de Pós-Graduação em Ciência e Tecnologia Ambiental; UFFS
• Palavras-chave em Português: Erva-mate; Cultura da erva-mate; Herbicidas; Plantas daninhas
• Link de acesso: https://rd.uffs.edu.br/handle/prefix/1360

The mate (Ilex paraguariensis St. Hil.), represents an alternative of agricultural exploitation for properties of the South of Brazil, and because it is an arboreal forest species found only to the south of South America, it presents potential for export. In addition the mate exerts a social and cultural function, mate has economic importance from small to large properties. Nevertheless, good management practices and cultivation are essential for high crop productivity. Among the management adopted in the mate plantations and that when not properly managed cause losses in productivity is the control of weeds. However, in most cases, the control is done by the chemical method with the use of herbicides. Nowadays scarce or absent are the records of the effect that herbicides can cause on mate. Therefore, the objective of this work was to evaluate the interference of weed species populations (experiment I) and multiple doses of herbicides (experiment II) on the morphophysiological characteristics of mate. Two experiments were carried out under greenhouse conditions at the Federal University of Fronteira Sul (UFFS), Campus Erechim / RS, in the agricultural year of 2015. For experiment I, the experimental design was a randomized block, arranged in a factorial scheme 4 x 6, with four replicates. In factor A, weed species (Urochloa plantaginea - papuã, Bidens pilosa - picão-preto, Ipomoea indivisa – corda-de-viola and Conyza bonariensis - buva) were allocated, and in B the populations of these species competing with the mate (0, 1, 2, 3, 4 and 5 plants per pot). The variables evaluated in the mate and weed were sub-stomatal CO2 concentration, photosynthetic rate, CO2 consumption, stomatal conductance of water vapors, transpiration rate, water use efficiency, height, diameter, leaf area, mass dry matter of the aerial part of the plants and only for the mate were evaluated the leaf concentrations of nitrogen, phosphorus, calcium and magnesium. For experiment II, the experimental design was a randomized block, arranged in a 4 x 7 factorial scheme, with four replications. In factor A, were allocated the herbicides doses (0, 0.5, 1 and 2 doses recommended) and in factor B the herbicides (tembotrione, chlorimuron-ethyl, oxyfluorfen, sethoxydim + diclosulam, metsulfuron-methyl, fomesafen + fluazifop-p-butyl and nicosulfuron). The variables evaluated were: phytotoxicity, height, stem diameter, chlorophyll content, sub-stomatal CO2 concentration, photosynthetic rate, CO2 consumed, stomatal conductance of water vapors, transpiration rate, water use efficiency, dry mass of part aerial and root. In experiment I, the papuã showed to be more competitive and significantly reduced the morphophysiological variables of mate. Weed coexistence reduces nutrient accumulation in leaf tissue of mate. The corda-de-viola was the least competitive species for nutrients and the picão-preto was the most competitive by phosphorus. In experiment II, the herbicides oxyfluorfen, fomesafen + fluazifop-p-butyl and nicosulfuron considerably affected the morphophysiological characteristics of the plants at all doses tested. Chlorimuron-ethyl and sethoxydim + diclosulam showed potential to be used in the mate until double the dose, since they showed low phytotoxicity and reduced interference in the morphophysiological characteristics of the culture.