Clipping effects upon primary productivity and senescence: study case on Festuca pallescens (St. Yves) Parodi in a Patagonian semiarid grasland, Argentina

BERTILLER, M. B. ; DEFOSSÉ, G. E

ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY

GAUTHIER-VILLARS/EDITIONS ELSEVIER

Lugar: Paris; Año: 1990 vol. 11 p. 79 - 92

1146-609X

The effects of partial clipping of the aboveground biomass of F. pallescens in field plots at a Patagonian grassland were investigated.  The values of aboveground biomass of the various categories of clipped, and intact plants were used to fit growth models of first order homogeneous differential equations, with which the rates of aboveground primary productivity and senescence were calculated.  Aboveground primary productivity in clipped plots lagged 30 to 60 days behind similar values observed in controls during the vegetative period. The differentiation of reproductive structures occurred only to a limited extent in clipped plants (fewer tiller/tussock) and the aboveground primary productivity during this period was lower as compared to controls.  The results indicate that clipping of aerial biomass restricts the reproductive effort and modifies the rhythms of productivity of this species.  Also, aboveground relative growth of clipped plants is compensatory during the vegetative period and under-compensatory during the reproductive period.