Soil water nitrate concentrations in giant cane and forest riparian buffer zones

Soil water nitrate concentrations in giant cane and forest riparian buffer zones along Cypress Creek in southern Illinois were compared to determine if the riparian zones were sources or sinks for nitrogen in the rooting zone. Suction lysimeters were used to collect soil water samples from the lower rooting zone in each of the two vegetation types. The cane riparian zone had a significantly lower mean soil water nitrate-N concentration (0.45 mg L-1) than the forest riparian buffer zone (4.29 mg L-1). This was attributed to higher litter C/N ratios in the cane, which likely resulted in greater microbial immobilization of nitrogen within the rooting zone.