English

De Oliveira Ferreira Ademir,Reichardt Klaus,Pivotto Bortolotto Rafael,Bavoso Larissa,Jorge Carneiro Amado Telmo,Purissimo Claudio,Graziele Kugler Mariacirc;Nne

doi:10.5897/ajar2013.6948

Abstract

One of the main survival mechanisms of weeds in constantly disturbed environments, specially the annual weeds, is their high production of seeds. In this study it was intended to evaluate the influence of different agroecosystems (vegetable garden, pasture, native field, soybean, dry bean and corn) on the strength of the seed bank, making quantitative and qualitative analyses. On each site, soil samples were collected, split to submit half to seed extraction by washing samples with water and counting the total number of seeds (quantitative analysis), and half to germination in trays placed in a greenhouse to evaluate weed emergence (qualitative analysis). The quantitative analysis of the agroecosystems showed that those cultivated with corn and vegetable garden presented best conditions for weed occurrence. The qualitative analysis resulted in the highest number of viable seeds for the vegetable garden (141,094,713 seeds, of which 74,965,862 were from monocotyledons plants and 66,128,851 dicotyledons). The weed seed concentration found for the vegetable garden is probably related to the management intensity in the area. The inverse is observed for the environments of less management intensity, as pasture and native field. Dry bean and soybean plots presented small seed bank and low emergence.   Key words: Vegetable garden, pasture, soybean, dry bean, corn, native field.

Highlights

The reserves of viable seeds in soil at the surface and in depth are known as seed bank (Gomes and Christoffoleti, 2008), other concepts or designations being found
In this study it was intended to evaluate the influence of different agroecosystems on the strength of the seed bank, making quantitative and qualitative analyses
The largest weed seed bank was found in the agroecosystem of corn (Figure 2), not statistically different from the vegetable garden

Summary

INTRODUCTION

The reserves of viable seeds in soil at the surface and in depth are known as seed bank (Gomes and Christoffoleti, 2008), other concepts or designations being found. The size and the composition of the weed seed bank are very important for the decision of integrated weed management strategies. The decision-making of weed management strategies is based on visual evaluations of the needed weed control intensity without much technical criteria It is important, for emerging technologies like precision agriculture, to develop control strategies based on estimations of the potential of the weeds in the soil. The understanding of the dynamics of a weed seed bank and the simulation of the emergency flux are among the most recent strategies used for weed control (Vivian et al, 2008) In this context, this experiment was carried out with the aim of evaluating the influence of different types of soil use, that is, different agroecosystems on their seed banks, making qualitative and quantitative analyses

MATERIALS AND METHODS

RESULTS AND DISCUSSION

Conclusions