CB DAVIS’s research while affiliated with The Ohio State University and other places

Biweekly elevation of available nitrogen and phosphorus concentrations in marsh surface waters did not alter the rate of Sparganium eurycarpum Engelm. or Typha glauca Godr. shoot decomposition. After 505 days, losses of shoot material totaled 39% for both species under fertilized and unfertilized conditions. However, Sparganium shoot litter with an initial nitrogen concentration of 1.41% lost 27% more dry weight over a 505-day period than did Sparganium with an initial concentration of 0.59%. Typha shoot litter with an initial concentration of 0.55% lost 2% more dry weight during 505 days than Typha tissues with an initial nitrogen concentration of 0.48%. During the 505-day sampling interval, quantities of nitrogen in shoot litter increased 31% for Sparganium and decreased 10% for Typha under unfertilized conditions. Unfertilized Sparganium shoot litter lost 2% and unfertilized Typha litter gained 25% of original phosphorus quantities. Under fertilized conditions, nitrogen quantities increased 35% for the 2 species. The quantity of phosphorus in Sparganium and Typha shoot litter increased 7 and 121%, respectively, with fertilization. Sparganium shoot litter with a high initial nitrogen concentration lost 50% of its original quantity of nitrogen over 505 days, but high-nitrogen Typha shoot litter gained an additional 19% nitrogen.