PARENT SESSION
Poster Session 39: Late Breaking and Newsworthy Posters
Friday, August 12, 8:30 AM - 10:30 AM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal
Seasonal dynamics of soil nutrient availability (C, N & P) under two leguminous tree species in a tropical semi-arid ecosystem.
Perroni Ventura, Yareni1, Montaña Carubelli, Carlos1, García-Oliva, Felipe2, 1 Instituto de Ecología A.C., Xalapa, Veracruz, Mexico2 Centro de Investigaciones en Ecosistemas, UNAM., Morelia, Michoacán, Mexico
ABSTRACT- We assessed seasonal dynamics of soil nutrients in a semi-arid region in Central Mexico under Prosopis laevigata, Cercidium praecox, and in open sites. Specifically, we evaluated processes that create and maintain availability of soil nutrients. We measure the concentration of C, N and P (total and available forms) and microbial C and N. We also measure CO2-C, net nitrification, C and N net mineralization and immobilization using laboratory incubations. Concentration of organic C, total N and microbial forms did not show seasonal changes and they were higher under P. laevigata, intermediate under C. praecox, and lower in open sites. These suggest an effect of the plant species on nutrient pools. The concentration of available forms of N and total P were similar under both species, but higher than in open sites. NH4, plant-available P and total P concentrations increased in the dry season, as well as NO3 concentration, but only under the two tree species. The data show that these plant species create and support the availability of soil nutrient in contrast with the open sites. Concentrations of labile C and CO2-C increased in the rain season. C-mineralization was higher under P. laevigata than under C. praecox, while open sites had the least during the rainy season. This suggests that the soil under P. laevigata has the highest availability of C-pools for soil microbial heterotrophic activity. Net nitrification and N-mineralization were higher under the two leguminous tree species than in open sites. The quality and amount of above and belowground litter can explain the differences between the three micro-environments studied.
Key words: soil nutrient availability, seasonal dynamics, Prosopis laevigata, Cercidium praecox