Competitive ability with weeds during the establishment of aries grass: morphological characteristics

ABSTRACT The aim of this research was to evaluate interspecific competition in Panicum maximum cv. Aries during the establishment period, studying the factors of shading and nitrogen levels. The levels of shading caused by the weeds ranged from 0% and 40% to 70% and 60% with no nitrogen and in the presence of nitrogen. Analyses were made of plant height, tiller dynamics, leaf area index (IAF), dry matter, senescent leaf material and relative competition intensity (ICR) in P. maximum cv. Aries when with weeds. The data were submitted to tests for homogeneity of variance and residual normality; analysis of variance (ANOVA), Tukey's mean difference test at 5% probability, and regression analysis were then carried out. The morphological and yield characteristics of P. maximum cv. Aries responded better where there was no interference from the weeds. Nitrogen contributed to greater development in P. maximum cv. Aries, but when coexisting with the uncut weeds, the weeds dominated the P. maximum cv. Aries. Cutting the weeds caused a reduction in the intensity of interspecific competition. The variable conditions of shade over time express different morphological responses in comparison to a homogeneous situation, mainly interfering in the speed of establishment of P. maximum cv. Aries.