Environmental Controls on Nitric Oxide Emission from Northern Chihuahuan Desert Soils

A survey of nitric oxide (NO) emission from Chihuahuan desert soils found mean NO fluxes <0.1 ng NO-N cm-2 h-1 during the dry season. These fluxes were at the lower end of the range reported for temperate grassland and woodland ecosystems. NO fluxes from wet or watered soils were higher (0.1-35 ng NO-N cm-2 h-1 ). Watering of black grama grassland soils produced an initial pulse of 12 ng cm-2 h-1 (12-h after 1-cm watering) with high fluxes sustained over 4 days with repeated watering. Initial pulses from shrubland soils were lower (maximum 5 ng cm-2 h-1 ), and fluxes declined with repeated watering. Repeated watering of creosotebush soils depleted the soil NH4 + pool, and NO emissions were directly related to soil...

Categories: Publication; Types: Citation, Journal Citation; Tags: Biogeochemistry, Springer

Potential environmental controls on nitrogenase activity in biological crusts of the northern Chihuahuan Desert

We used the acetylene reduction assay to analyse soil nitrogenase activity at the Jornada Long-Term Ecological Research site (northern Chihuahuan Desert, New Mexico, U.S.A.). A three-day irrigation and fertilization experiment showed that water and carbon (glucose) enhanced nitrogenase activity, while NH4NO3 reduced activity. Micronutrient (Mo, Fe, Co) and phosphorus fertilization had no significant effect. A survey of Jornada Basin soils did not reveal an inverse relationship between nitrogenase activity and the ratio of available nitrogen (N) to phosphorus (P), as hypothesized; however, the highest rates of nitrogenase activity were detected in tarbush floodplain soils with a low ratio of available N to P. These...

Categories: Publication; Types: Citation, Journal Citation; Tags: Chihuahuan Desert, Jornada Long-Term Ecological Research (LTER) site, Journal of Arid Environments, biological soil crust, nitrogenase activity