Effects of N placement, carbon distribution and temperature on N2O emissions in clay loam and loamy sand soils. (7th March 2013)

• Record Type: Journal Article
• Authors: Xue, Y.; van, H. M.; Schindelbeck, R. R.; Moebius‐Clune, B. N.; Melkonian, J. J.; Graham, C.; Yang, P.
• Is Part Of: Soil use and management. Volume 29:Number 2(2013:Jun.)
• Page Start: 240
• Page End: 249
• Publication Date: 2013-03-07
• Subjects: Soil management -- Periodicals; 631.4
• DOI: 10.1111/sum.12037
• Languages: English
• ISSNs: 0266-0032

Abstract

<abstract abstract-type="main" id="sum12037-abs-0001"> <title>Abstract</title> <p>Changes in the profile distribution of soil C stocks for conventional versus no‐tillage can affect N<sub>2</sub>O losses. Uncertainty remains whether deep N placement into a wetter layer in humid areas would affect N<sub>2</sub>O losses. This study evaluated the effects of soil carbon profile distribution (inverted, normal), depth of nitrogen placement (5 cm, 15 cm), temperature (10, 20 and 30 °C) and soil texture (clay loam, loamy sand) on N<sub>2</sub>O emissions from soil cores in a 216‐h incubation after simulated rainfall. N<sub>2</sub>O losses were larger from the clay loam than from the loamy sand, and cumulative N<sub>2</sub>O emissions from the inverted profile, with greater C levels at depth, were more than those from the profile with more C near the upper surface. Cumulative N<sub>2</sub>O losses from the inverted clay loam profile with deep N placement (1.16 mg N per kg dry soil; 0.71% of applied N) on average were almost double those in the loamy sand (0.62 mg N per kg dry soil; 0.42%). The smallest N<sub>2</sub>O losses were measured from the profiles with more C close to the upper surface with a shallow placement of N for the clay loam (0.19 mg N per kg dry soil; 0.12%) and loamy sand (0.33 mg N per kg dry soil; 0.23%). An exponential relationship between N<sub>2</sub>O fluxes and temperature was measured. We conclude that large N<sub>2</sub>O losses may occur under the combination of greater soil C content at deeper layers (ploughed soils) and moist profiles after N application (humid regions). Deep N placement appears to aggravate rather than ameliorate these concerns.</p> </abstract>