Rp. Griffiths et al., CHEMISTRY AND MICROBIAL ACTIVITY OF FOREST AND PASTURE RIPARIAN-ZONE SOILS ALONG 3 PACIFIC-NORTHWEST STREAMS, Plant and soil, 190(1), 1997, pp. 169-178
Throughout the United States, agricultural practices are responsible f
or large quantities of nutrients entering lakes and streams. Previous
studies have shown that forested riparian areas can filter nutrients f
rom surface runoff and groundwater that may potentially contaminate la
kes and streams. This study examined seasonal differences in soil chem
istry and soil microorganisms in paired mixed-forest riparian and past
ure systems, the aim being to gain understanding of the sequestering o
f N and P. The forest soils retained higher levels of organic C and N,
mineralizable N, extractable P, and fungal biomass, and had higher re
spiration rates than pasture soils. These findings suggest that forest
ed riparian zones have a greater capacity than pasture soils to seques
ter C and retain nutrients. In past studies, fungal biomass has been s
hown to be less than bacterial biomass in grassland soils, but in this
study, fungal biomass was greater than bacterial biomass throughout t
he year in both forest and pasture soils.