Open Access

ARTICLE

Effect of post-fire defoliation on growth of two native grasses in the Caldenal, Argentina

Peláez¹ DV, RM Bóo², MD Mayor³, OR Elia⁴, SA Martínez⁵

1 Departamento de Agronomía, Universidad Nacional del Sur (UNS), CIC, CERZOS, Altos del Palihue, 8000 Bahía Blanca, Argentina.
2* Departamento de Agronomía (UNS), CIC, CERZOS, Altos del Palihue, 8000 Bahía Blanca, Argentina.
3**, 5 Departamento de Agronomía (UNS), CIC, CERZOS, Altos del Palihue, 8000 Bahía Blanca, Argentina.
4 Departamento de Agronomía (UNS), CONICET, CERZOS, Altos del Palihue, 8000 Bahía Blanca, Argentina.
Address Correspondence to: D.V. Peláez; e-mail: dpelaez@criba.edu.ar; fax 054-0291-4595127; Phone 054-0291-4595102.

* Corresponding Author:* Dr. Roberto Miguel Bóo passed away on 30 October, 2007.
** Agr.Eng., M.Sc. Mirta Doris Mayor passed away on 4 December, 2008.

Phyton-International Journal of Experimental Botany 2009, 78(all), 17-24. https://doi.org/10.32604/phyton.2009.78.017

Abstract

Plant growth in semiarid rangelands may be affected by time grazing is excluded during the post-fire regeneration period. The objective of this field work was to study the effect of post-fire defoliation at different phenological stages [vegetative (early-season defoliation) and internode elongation (late-season defoliation)] on growth of Piptochaetium napostaense and Poa ligularis, two very important perennial native grasses in the temperate semi-arid region of central Argentina (Caldenal). In general, the post-fire defoliation treatments did not affect the number of green leaves on tillers of P. napostaense. Early-season post-fire defoliation generally reduced the number of green leaves on tillers of P. ligularis in comparison to those in control plants. Late-season defoliation, however, usually increased the number of green leaves on tillers of P. ligularis. Nevertheless, very few significant (p<0.05) differences were detected within either one or the other phenological stage. Height and total green length (leaves + stem + sheaths) of tillers on plants of P. napostaense and P. ligularis exposed to defoliation were lower (p<0.05) or similar (p>0.05) than values on non-defoliated plants, respectively. Immediately after early- and late-season defoliation treatments, relative growth rates for tiller height and total green length were reduced (p<0.05) on plants of both species with respect to control plants. Our results suggest that a one-year-period without severe defoliations after fire would be at least necessary for not risking the persistence of these perennial grasses in the Caldenal community.

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