Resumo

RANGEL MARQUINA, Sairo et al. Dry matter production and chlorophyll content index in mixed pastures of the Venezuelan humid tropics. Acta Agron. [online]. 2023, vol.72, n.2, pp.156-160.  Epub 08-Maio-2024. ISSN 0120-2812.  https://doi.org/10.15446/acag.v72n2.107536.

An ecophysiological study was carried out in a mixed pasture composed mainly of grasses Megathyrsus maximus and Brachiaria arrecta in the South of Lake Maracaibo, Venezuela, under tropical rainforest conditions, with the purpose of determining the possible beneficial association between these tropical grasses. Seven paddocks were sampled, taking three subsamples of each, both in the dry and wet season; the technique consisted of throwing a random metal frame in a zigzag shape. The chlorophyll content index (CCI) and the foliar and root dry weight were measured. Data were analyzed using the Mann-Whitney U nonparametric statistical test. No differences were found for the root dry weight variable between the two seasons for the two species. Regarding the leaf dry weight, B. arrecta did not show differences between the seasons, while for M. maximus, it was higher in the wet season. The CCI in B. arrecta did not show differences between the seasons, while in M. maximus, it was higher in the wet season. According to the results, it was concluded that this association is beneficial because M. maximus favors B. arrecta possibly due to a nurse effect, which allows this species to have less abiotic stress and therefore greater carbon fixation and greater availability of plant biomass during the most critical season, namely the dry season.

Palavras-chave : Brachiaria arrecta; chlorophyll meter; Megathyrsus maximus; mixed pasture.

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