TITLE:
Soil Seed Bank Phytosociology in No-Tillage Systems in the Southwestern Amazon Region
AUTHORS:
Lidiane A. Vargas, Alexandre M. A. Passos, Veronice A. Marcílio, Francis A. Brugnera, Vivianni P. D. Leite, Rogério S. C. Costa
KEYWORDS:
Sorghum sudanense, Phytosociology, Integrated Management, Sustainability, Brazilian Amazonia
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.8 No.13,
December
20,
2017
ABSTRACT: Understanding the ecological dynamics of weed populations
in no-tillage systems is important to establish strategies for integrated weed
control capable of increasing agroecosystem sustainability. This study sought
to evaluate the effect of succession systems on the seed bank in a no-tillage
system. The effects of fifteen succession systems, composed of seven grasses,
seven Leguminosae, and a fallow
condition, were evaluated on the seed bank at two soil depths (0 to 10 and 10
to 20 cm). The species found in the seed bank were quantified and identified by
species and family. The precision of sampling, density, dominance, the indices
of diversity of Simpson and Shannon-Weiner; index of sustainability; analysis
of groupings of dissimilarities; and the value of importance of each species
were calculated. High weed diversity was observed; 29 species were counted,
including members of 12 different families. The highest expression of weeds was
observed at soil depths of 0 to 10 cm. The Simpson and Shannon-Weiner
coefficients indicated high diversity in both systems of succession. The index
of sustainability did not indicate significant alterations in the different
systems of succession. The coefficients of confenetic correlation were 0.74%
and 0.82% for the 0 - 10 and the 10 - 20 cm soil depths respectively. It is
concluded that there is a high diversity of weeds in the agroecosystems of
Amazonia, and different cover crops promote modifications in the community and
expression of the weeds’ seed bank.