Floristic and Phy Tosociological Survey of Weeds: a Review of Methods Employed

Abstract

Current survey aims at knowing, presenting and analyzing the evaluation methods of the floristic and phytosociological composition of weeds from the main agricultural environment. It is based on bibliographical data from several authors within the extant literature. Besides specific methods, such as density and frequency, other phytosociological methods were investigated when used in the survey on the occurrence of economically interesting weeds mentioned in the literature and also in the variability of methods that may be employed on the field for weed management. It should be recommended that weed identification may be done after harvest since during this period infestation is highest and richness abounds. Plant identification changes according to perennial or annual culture. Several cultivars should be evaluated during different periods than those recommended, such as the caupi-beans, evaluated during the vegetative phase, and guaraná, evaluated by the plant´s age. Evaluation method vary according to authors and it is rather difficult to select and standardize a method for the floristic and phytosociological evaluation of invading plants within the integrated management of weeds, and in the production of scientific results. The above characterizes the diversity and complexity of agroecosystems within the context of production systems. Further studies are required.