Retention of particles and nutrients in the root zone of a vegetative buffer zone : effect of vegetation and season

Abstract

Vegetative buffer zones (BZs) along streams retain particles and nutrients like phosphorus (P) and nitrogen (N), from agricultural runoff. An experiment with drained soil columns was established to study the retention of particles and nutrients from artificial agricultural runoff. The effect of vegetation (grass versus trees, alder versus aspen) and season was examined. The retention of particles and P was significantly higher in columns with trees as compared with that in column with grass. In general this was also the case for organic carbon (C org ) and N. Columns with aspen and alder had equal retention efficiency for particles, (C org ) and P, and in most cases also for N. Thus alder and aspen seem to be equally suitable in forest covered BZs. The retention efficiency of nutrients was generally better during spring, summer and early autumn as compared with that during late autumn. Uptake of nutrients in vegetation seemed to be an important retention mechanism.