Field Measurement of Denitrification: I. Flux of N 2 and N 2 O

作者：D. E. Rolston, D. L. Hoffman, D. W. Toy · 发表于：Soil Science Society of America Journal · 年份：1978 · DOI：10.2136/sssaj1978.03615995004200060004x · 被引用次数：143 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Rice Cultivation and Yield Improvement

Abstract Absolute amounts and rates of denitrification from a Yolo loam (Typic Xerorthents) field profile were studied in relation to the influence of soil‐water content, organic C source, and soil temperature. Field plots were intensely instrumented with soil atmosphere samplers, tensiometers, and thermocouples. Soil‐water contents were maintained constant with a spray irrigation system activated at frequent time intervals. The upper 15 cm of soil was maintained at soil‐water pressure heads ( h ) of −15 and −70 cm of water for the two different water regimes of the experiment conducted at a soil temperature (5 cm depth) of 23°C. Soil‐water pressure heads were maintained at −8 and −50 cm for the two water regimes conducted at 8°C. Plots cropped with ryegrass, uncropped plots, and plots to which manure was mixed in the top 10 cm of soil were used to establish three different C levels. Fertilizer was applied at the rate of 300 kg N ha −1 as KNO 3 enriched with 20 and 40% 15 N for the h = −15 or −8 and h = −70 or −50 cm treatments, respectively. The flux of gases at the soil surface was measured from the accumulation of N 2 O and 15 N 2 beneath an air‐tight cover placed over the soil surface for 1 or 2 hours per day. Denitrification from gas fluxes occurred for the 23°C experiment in order of decreasing magnitude in manure ( h = −15 cm), manure ( h = −70 cm), cropped ( h = −15 cm), cropped ( h = −70 cm), uncropped ( h = −15 cm), and uncropped ( h = −70 cm) plots. Approximately 7...