EFFECT OF CARBON SOURCE AND NITROGEN ON UREASE ACTIVITY IN A SPHAGNUM PEAT MEDIUM

Sphagnum peat moss was supplemented with 0, 0.01, 0.1, or 1.0 mg as C/cm3 of medium using glucose, galactose, succinate, or acetate as a carbon source. These treatments were factorially combined with 0, 30, or 60-mu-g N/cm3 using ammonium sulfate as the nitrogen source. Medium treatments were then incubated at 20-degrees-C and 40% water holding capacity. Urease activity was determined immediately prior to treatment (day = 0), and 7, 14, and 21 days following treatment. In another study, sphagnum peat was treated with 1.0 mg C/cm3 of medium using galactose as a carbon source. These treatments were factorially combined with 0 or 60-mu-g N cm3 medium using either ammonium sulfate or urea as a nitrogen source. Treatments were incubated and assayed for urease activity as described for the previous experiment. In the first experiment, the addition of carbon stimulated urease activity with activity being greatest for the highest rate of carbon. Treatments receiving the two monosaccharides, glucose and galactose, showed greater urease activity levels with treatments receiving galactose having the greatest urease activity. The addition of ammonium retarded the increase in urease activity from the addition of carbon. In the second experiment, in the absence of galactose, urease activity increased in samples supplemented with urea as compared to when ammonium was added. When galactose was present, the addition of urea had no effect on urease activity as compared to treatments receiving ammonium.