Author : Catherine DeFotis
Publisher :
ISBN 13 :
Total Pages : 34 pages
Book Rating : 4.:/5 (842 download)
Book Synopsis Effects of Nitrogen Deposition on Nitric Oxide (NO) Efflux of Chaparral Soil in Southern California by : Catherine DeFotis
Download or read book Effects of Nitrogen Deposition on Nitric Oxide (NO) Efflux of Chaparral Soil in Southern California written by Catherine DeFotis and published by . This book was released on 2013 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Large amounts of nitrogen (N) are being deposited in urban areas of southern California, which are altering the carbon (C) and N cycling of semi-arid shrubland ecosystems. It is possible that these N inputs are exceeding biotic demand, leading to "N saturation" and increasing the losses of N from leaching and gaseous efflux. N input to soil increases the microbial process of nitrification, which releases nitric oxide (NO) into the atmosphere as a byproduct. The production of NO in chaparral soils is not fully characterized and more experimentation is needed to understand the environmental controls on NO flux from semi-arid soils. Thus, a laboratory incubation experiment was executed to see how NO efflux of chaparral soil varied as function of N addition (0-5 gN/m2) under various soil temperature (0-40°C) and moisture conditions (10.5-72.7%). Based on limited research, I hypothesized that the NO efflux of southern California chaparral soils would i) increase as a function of N addition, ii) present an optimum response as a function of soil moisture, and iii) increase as an exponential function of temperature. Results indicate that NO efflux increased linearly with N addition, supporting the hypothesis that an increase in N availability will increase NO efflux. NO efflux also increased as a function of soil temperature and was well-described using the Arrhenius model, supporting hypothesis 3, and the NO efflux followed an optimum response as a function of soil moisture, supporting hypothesis 2. In general, the greatest NO efflux was observed from soil samples treated with 5 gN/m2 (NH4)2SO4, brought to 25% water-filled pore space (WFPS), and at a temperature of 34.4°C. There was high sensitivity to temperature changes between 0 and 5 gN/m2 (NH4)2SO4 and in soil moistures