Effects of clayish and sandy soils on the growth of Prosopis argentina and P. alpataco seedlings

VILLAGRA, P.E.; CAVAGNARO, J.B.

ECOLOGÍA AUSTRAL

Asociación Argentina de Ecología

Año: 2000 vol. 10 p. 113 - 121

0327-5477

Prosopis alpataco Burk. and P. argentina Phil. occupy areas with different soil character-istics within the arid zone of Argentina. Prosopis alpataco occurs in periodically flooded, clayishand saline soils, whereas P. argentina occurs in non-saline sand dunes. The capability to occupythese different habitats might be related to the presence of different adaptive features in thesetwo species. We analyzed seedling growth of both species on clayish and sandy soils. Their emer-gence percentages, seedling height, biomass, and leaf area were measured in a factorial experi-ment (speciesxsoils) carried out in a greenhouse. Both species showed a higher growth rate(height, biomass, leaf area and number of leaves and shoot-root ratios) in clayish soils. In sandysoils, the growth rate of P. alpataco was lower than that of P. argentina, indicating that the detri-mental effects of sandy soils were greater for P. alpataco. We suggest that soil effects on growthcould be due to the differences in nutrient (especially nitrogen) availability, and that P. argentinashows adaptations to sandy soils which are absent in P. alpataco. These results could explain theexclusion of P. alpataco from sandy soils but not that of P. argentina from clayish soils. Exclusion ofthis last species should be associated with other environmental factors like flooding or salinity, orwith biological factors such as competition.