Agriculture has been practised in the Argentine Pampa region for more than a century. This long history of disturbance has strongly modified the native vegetation of the region. Some original species have disappeared or its area has been remarkably reduced. The objective was to evalúate vegetation changes over time after the abandonment of agriculture practice. Our hypothesis was that over time vegetation in this region will evolve towards a "flechillar" (Stipa spp. community) similar to the original vegetation. The experiment was conducted at Zavalla (Santa Fe) Argentina (33° 01' S, 60° 53' W and 50 m.a.s.1.). Vegetation evolution was studied during 15 years (1982-1997) after abandonment, considering four initial crop situations (i.e. wheat, soybean,... |