Abstract

ANZALONE, Alvaro; ARIZALETA, Miguel  and  GONZALEZ, Mariela. Weed populations in ‘Valencia’ orange groves and their relationship with soil characteristics in two municipalities of Yaracuy State, Venezuela. Bioagro [online]. 2012, vol.24, n.1, pp.23-32. ISSN 1316-3361.

Weed flora in ‘Valencia’ orange groves in Bolivar and Manuel Monje municipalities of Yaracuy State, Venezuela, was characterized. A total of 506 weed samples (0.5 m² each) coming from 236 citrus farms were evaluated. Weed population parameters, weed ground cover, and importance value index (IVI) of each species were determined. The soil and leaf mineral contents were available and a binary regression was performed between the presence or absence of weed species and soil parameters, as well as correlations between density and ground cover of most important weeds with parameters of soil and crop plants. It was found 103 species belonging to 25 botanical families, with 23 species representing 80% of the total IVI. The density and weed ground cover were 44.06 plants·m^-2 and 61.8% respectively. The five most important species were Cyperus rotundus, Panicum maximum, Cynodon dactylon, Waltheria americana, and Ipomoea tiliacea. A low number of significant correlation and regressions were detected, indicating that the evaluated soil characteristics would not be the most important to define the trend of weed population variables, but suggest interesting relationships that can later be studied more particularly.

Keywords : Citrus; ground cover; density; weeds.