Abstract

RAMIREZ REYNOSO, Omar et al. Population dynamics of stems and stability index of the llanero grass. Rev. Mex. Cienc. Agríc [online]. 2020, vol.11, n.spe24, pp.23-34.  Epub May 07, 2021. ISSN 2007-0934.  https://doi.org/10.29312/remexca.v0i24.2355.

In the tropics of Mexico, grasslands are the basis for feeding ruminants. The objective of the study was to determine the density, rate of appearance, death and survival of the population of stems of the Llanero grass (Andropogon gayanus Kunt) harvested at different regrowth ages (EA: 7.14, 21, 28, 35, 42 , 49 and 56 d), in two growth periods, dry season with irrigation and rainy season. The EA (treatments) were assigned to four experimental units of 3 m2, using a randomized complete block design, with four replications. In both growth periods, the stem density increased until the 28 days of regrowth later, decreased until the end of the study with greater intensity during the dry period with irrigation compared to the rainy season (325 and 378 stems m-2, respectively). There was greater appearance and death of stems in the dry period with irrigation (97 stems 100 stems-1 week-1). The population stability index was greater or close to one during the irrigated drought, while, in rains from the 42 days of regrowth, this was less than one. In conclusion, it was obtained that regrowth ages from 7 to 28 days do not compromise the population stability of stems and favor the persistence of the grasslands. Older regrowth ages during the rains do not allow to recover the stem population, which favors population instability.

Keywords : death rate; stem population; stem survival.

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