Title: Seasonality effect on soil quality for forest restored lands in Heredia-Costa Rica
Abstract: Soil properties not only affect the stand development but have a strong relation with the soil moist content, which substantially varies between seasons on the tropics. This study has been conducted to evaluate the effect of seasonality and forest cover on soil properties on four restoration sites, where the cover types were grassland, regeneration, secondary forest of (15 years and a 30 years). It was held during the dry and rainy season and compared indicators of chemical, physical, biological and biochemical soil properties for each site. Soil quality index methodology was used to transform different unit variables into a subjective value, allowing to add them for a simpler comparison between sites and seasons. A simple random sampling method was applied, consisting of ten samples taken at a depth of 0-30 cm, for each site. Statistical analysis of multivariance (MANOVA, Biplot and Dendrogram) were preformed in order to compare sites and seasons. There were significant differences registered between seasons for all variables, except pH (p=0,05) which was acid on all sites; also, between forest covers on each season period, significant differences for most variables were obtained. According to multivariance analysis, there was a significant difference between seasons and forest covers in all cases. Regarding the soil quality index, the effect of seasonality over chemical properties negatively affected the soil quality of forest type covers. The dendrogram states that there is a clear aggrupation of sites due to seasonality; shifting the affinity from grasslands to secondary forest (15 years) for regeneration during the rainy season. Therefore, the study evidences that seasonality influences soil, especially related to chemical properties, which alters the soil quality on each site and between them. Restoration stages and the starting point on soil degradation also affected soil quality index, having a better index position the secondary forest of 15 years than the others.
Keywords: Andisol, forest restoration, seasonality, soil quality, tropical cloud forests.