Abstract

BLANCO, María del Carmen; AMIOTTI, Nilda Mabel  and  HERRERA, Lourdes Soria. Changes induced by tree olives implantation on soil properties in southern bonaerense. Cienc. suelo [online]. 2005, vol.23, n.2, pp.189-196. ISSN 1850-2067.

In small sectors of the southern Pampean region affected by wheat cultivation, the native grassland steppe has been replaced by Olea europaea L. mounts, which introduced a drastic modification of vegetation as an active factor of pedogenesis. The impact of this change was evaluated in the A horizons of the predominant soils (Petrocalcic Paleustolls) under olives mounts of approximately 50 years (LV2) and has been compared to that derived after the traditional rotation wheat (LV3)-native vegetation (LV1). Chemical analyses were performed to analyze the variables commonly used in the evaluation of soil fertility: bulk density (Da), texture, pH, organic carbon (CO), total nitrogen (Nt), available phosphorous (Pd), CIC, exchangeable bases. Moreover, a micromorphological study was done. Increments of 90% magnitude order in CO content, 70% in Nt and >100% in Pd were detected under olive trees cultivation related to a high biomass of olive trees and grass vegetation in the epipedon and to the intense melanization that sustain C/N relationship in acceptable levels. All variables decrease under wheat cultivation (LV3). At microscopic level a higher degree of humic pigmentation, a stronger microstructure (subangular blocky and spongy), darker colors and a higher frequency of excrements were observed under olives compared to grassland and wheat cultivation. The three compared situations denote the notable effect of vegetation change though variables do not reflect a soil quality decrease owed to olive trees introduction. On the contrary, soil physicho-chemical properties proved a substantial improvement contrasting with the detrimental effects in soils affected to wheat cultivation under the current management practices in the studied region.

Keywords : Olives-wheat/grassland rotation; Soil properties; Fertility; Soil quality.

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