Monument Canyon Research Natural Area: Soil Nitrogen Cycling Characteristics

White, Carleton

Although soils collected at some sites showed the expected pattern of low net nitrogen mineralization and nitrification rates, many soils showed different patterns. Part of the reason for these changes may be different monoterpenes produced by trees that differ genetically. The presence of such different patterns in such a relatively close position in the field may be useful in future investigations to identify the degree of control that plant genetics (as expressed by differing monoterpene composition and concentrations for genetically different trees) plays in ecosystem-level nutrient cycling. Future research on comparative monoterpene composition and their persistence in the field is strongly recommended at this site. With respect to fire management, potential productivity at this site is already high. Given enough water (which would limit decomposition and production) and enough other resources (light, or another nutrient could become limiting) productivity at this site could be very high. This may be the case (high productivity), but the productivity is distributed among a high number of individuals. As recognized by Peterson and Rasmussen (1986), this high stocking also is very hazardous from a fire prevention and protection perspective. The fire hazard represents a greater threat to the site than potential nitrogen limitation, which does not appear limiting based on results of this study.