Charral Project -- soil phosphorus availability and other environmental conditions

Sampling in 1997 showed that there was limited variation in soil P availability with distance from forest, and that topographic position within our study sites did not influence P availability. Quantification of soil moisture levels showed in in all five sites, surface soil moisture content was greater in the pastures than in adjacent forest.

This figure shows typical P saturation curves from three of the sites. Curve values are means of all soils sampled at each site indicated.

Here we see correlation between soil NaF pH and both PAM and % P fixation. Clustering of points represents significant site differences.

Similar to the figure above, this shows the correlation between soil NaF pH and C:N ratio, as well as Effective Cation Exchange Capacity. Clustering of points represents significant site differences.

To determine if surface soil moisture levels were possible causes of limited forest regeneration, we sampled the upper 15 cm of soil for moisture levels in 1998. This figure shows the mean of several readings along two transects, at multiple distances from forest, in each site. Although there is much spatial variation, there is a strong pattern of greater soil moisture levels in the pastures than in the forest, at all sites.