| Precipitation pulse event effects on the activities of amidase, phenol oxidase, alkaline phosphomonoesterase, and protease and the potential bioavailability of organic macronutrients in soils of the Mojave Desert were investigated. Soil samples were collected immediately before and for five days after a simulated precipitation event and analyzed for enzyme activities. For potential bioavailability measurements, soils were collected and subjected to amendment with buffered solutions of various enzymes. The products of each enzyme reaction were measured and bioavailability calculated. In general, there were no significant differences between watered and unwatered plots over the six-day sampling period. Significant differences between microsites for all enzyme activities were found. Measurements of bioavailability found that 14.5 and 9.7% of cellulose-C, 60.0-97.8 and 61.2-100.0% of protein-N, and 44.0 and 57.5% of organic P was potentially bioavailable in interspace and shrub soils, respectively. There were significant differences between microsites for potential bioavailability except for protein-N. |
