Controle alternativo de plantas daninhas, eficiência da fixação biológica do N2 atmosférico pelo feijão de porco e seu efeito inibidor sobre as mesmas.

Abstract

The control of weeds by the pork bean Canavalia ensiformis D.C. and its proven potential age in fixing N-atmospheric when in symbiosis with bacteria of the genus Rhizobium aimed the use of this legume in combating the ginger grass Paspalum maritimum Trim, invasive plant that occurs frequently in our region. The experiments were conducted under greenhouse conditions using yellow latosol from a capoeira plant in the municipality of Igarapé-Açu-Pa. Seeds of C. ensiformis were planted in plastic pots, capacity 3 Kg; the experimental design was entirely randomized, with 3 treatments and 4 repetitions, being: a) T1 - Soil inoculated with Rhizobium strain; b) T2 - Seed inoculated with Rhizobium strain; c) T3 - Witness. At flowering time, the plants were harvested, where nodule weight, nodule number, root weight and aboveground weight were analyzed. Strains of Rhizobium bacteria from the legume nodules were isolated, purified and characterized in the laboratory. P. maritimum tubers were planted in clay pots with 1.5 kg of soil capacity. The experimental design was entirely randomized with 4 treatments and 4 repetitions, which were: T1 - nodule extract; b) T2 - root extract of nodules; c) T3 - extract of roots without nodules; d) T4 - control. These extracts were prepared from the maceration of nodules and roots of C-ensiformis. It was verified that the extract of roots without nodules did not present any harmful effect on ginger grass germination; extract of roots with nodules inhibited germination; extract of nodules inhibited 100% germination.