Crescimento e rendimento do milho sob interferência da tiririca

Abstract

ResumoObjetivou-se neste trabalho avaliar a interferência da tiririca (Cyperus rotundus) sobre o crescimento e rendimento de grãos da cultura do milho. O experimento de campo foi realizado sob o delineamento experimental inteiramente ao acaso, com três repetições. Os tratamentos foram constituídos do convívio do milho com nove densidades de tiririca (0, 10, 30, 50, 90, 110, 130, 160 e 260 manifestações epígeas m -2 ). No florescimento da cultura fez-se a medição da altura das plantas, da inserção das espigas e a massa seca total das plantas de milho. Por ocasião da colheita foram determinados a massa de espigas, o rendimento de grãos e a massa de 100 grãos. O incremento da densidade de tiririca aumentou a altura de plantas e de inserção da primeira espiga do milho. Observou-se também redução no acúmulo de massa seca total, na massa de espigas e de 100 grãos e na produtividade do milho em todas as densidades avaliadas. A interferência da tiririca reduz o crescimento do milho com consequências diretas na produtividade de grãos da cultura. Palavras-chave: Cyperus rotundus, Zea mays, competição, produtividade AbstractThis research aimed evaluates the influence of purple nutsedge (Cyperus rotundus) on the agronomic performance of maize. We conducted a field experiment at Viçosa, MG, in completely randomized design experimental with three replications. The treatments consisted of the interaction of maize with nine nutsedge densities (0, 10, 30, 50, 90, 110, 130, 160 and 260 plants m -2 ). In the flowering culture was made the measurement of plant height, the insertion of the corn ears and the total dry matter of corn plants. At harvest were determined ear weight, grain yield and 100-grain weight adjusted to 13% moisture. Higher density of nutsedge increased plant height and the insertion of the first corn ear. We also observed a reduction in total dry matter accumulation, ear weight, 100-grain weight and grain yield in all densities evaluate. Nutsedge control, even at low densities is necessary because the presence of this plant promotes negative effect on growth and development of corn with a direct consequences on crop productivity.

Densidad de siembra y comportamiento agronómico de tres variedades de maíz morado (Zea mayz L.)

“…La densidad de siembra depende de la fertilidad del suelo y del objetivo de estudio [20,23]. Asimismo la aparición de malas hiervas en el cultivo maíz causa pérdidas que limitan el rendimiento de grano [24].…”

ALLELOPATHIC POTENTIAL OF Cyperus rotundus L. EXTRACTS ON GERMINATION AND COWPEA SEEDLING ESTABLISHMENT

“…Weeds can be defined as all plants whose advantages have not yet been discovered or those that negatively interfere with man's objectives (FISHER, 1973;SILVA et al, 2015). It is worth mentioning that the negative effects caused by the presence of weeds should not be attributed exclusively to competition, but rather to a total resultant of environmental pressures such as competition, interference at harvest, allelopathy, etc.…”

Growth and mycorrhizal colonization of maize plants treated with aqueous extracts from nonmycorrhizal weeds

“…The damage caused by allelopathic substances, either at the beginning of crop development or in the vegetative phase (Silva et al, 2015), interferes with the production of grains, which can result in significant losses, especially if the weedy plant is resistant to herbicides (Webster & Nichols, 2012). Determining whether the cause of these losses is due to the action of the allelochemicals on the plant, on the AMF, or on both, becomes relevant in an agronomic context.…”

“…Purple nutsedge is a species with highallelopathic potential; several reports show its negative action on seed germination and initial growth of maize seedlings (Hamaiyn et al, 2005) and other Poaceae species, as well as on grain production (Silva et al, 2015). Although no reports were found with respect to knotweed, the family to which it belongs, Polygonaceae, is known to contain species that produce a number of biologically active compounds, such as emodin, a multi-action anthraquinone (Fan et al, 2009) frequently associated with inhibition of seedling growth by retarding the elongation of the root and the hypocotyl.…”