Quantification of the weed seed bank under different soil management systems

The composition, dynamics and longevity of the soil seed bank is variable depending on the management system, climatic conditions and weed species present. Thus, the objective was to evaluate the quantification of the seed bank of weeds in the soil under different soil management systems. The experiment was carried out in a cerrado area, in the Embrapa experimental field and later in the greenhouse of the Agronomy course at the Federal University of Roraima, Boa Vista, Roraima, Brasil. A completely randomized design in a 5x4x2 factorial scheme with four replications was used. The treatments consisted of the associated use between five different soil management systems (native vegetation, minimum cultivation, no-tillage system, conventional system and conventional system with crop rotation), four soil depths (0-5; 5-10; 10 -15 and 15-20) cm and two soil samples (unformed and deformed). The no-tillage system proved to be efficient in the control of weeds, since the number of germinants was lower than that observed in the conventional, conventional system with rotation and native vegetation. The greatest number of germinants were found in the deformed samples and at depths 0-5 and 5-10 cm from the soil.