Resumo

ALVAREZ ADAN, Adrián. Variations of the growth periods for three tropical pastures, under the effects of climate change. Pastos y Forrajes [online]. 2019, vol.42, n.2, pp.104-113. ISSN 0864-0394.

The objective of this study was to analyze the changes of the growth periods for three tropical pastures, under the effects of climate change in Cuba. Information from a 30-year record (baseline 1961-1990) of monthly mean temperature and rainfall was used, from the database of the Climate Center -belonging to the Cuban Institute of Meteorology-, corresponding to 61 meteorological stations. The reference evapotranspiration was calculated by Penman Monteih’s formula, modified by FAO and adjusted to local climate conditions. The water deficiencies, of the beginning and end dates of the growth periods, and of the aridity index, were analyzed. For the analysis of future climates, daily outputs of the General Circulation Model Echan4 were used, forcing the emission scenarios A2 and B2. The growth period, for 2071-2099, will start with a delay of between 12 and 15 tens for Cynodon nlemfuensis Vanderyst and Cenchrus purpureus (Schumach.) Morrone. In contrast, an advance of the ending date of the period between the second and third tens of November for C. nlemfuensis and C. purpureus, and in the first ten days for Megathyrsus maximus (Jacq.) B.K. Simon & S.W.L. Jacobs, is foreseen. It was proven that the climate of Cuba will undergo an extreme desertification process, and will be classified as dry sub-humid. It is concluded that the performance of rainfall and crop evapotranspiration have a marked impact on the duration of the growth period of the studied pasture species, with a reduction of this period, which will be shown in the delay of the beginning dates and advance of the ending dates. This would have wide repercussion on the duration of the phenological phases, yield components and crop nutritional quality, as well as the appearance of pests and diseases.

Palavras-chave : climate; Cynodon nlemfuensis; Cenchrus purpureus; Megathyrsus maximus.

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