Soils and nitrous oxide research

Abstract

Between 1990 and 2008, Soil Use and Management has published around 42 articles which have dealt with nitrous oxide (N 2 O) emissions from soils. The importance of this subject to readers of the journal has increased rapidly in recent years. A substantial number of these papers have appeared in two supplements. These were 'Soils and the Greenhouse Effect', vol. 13 (4) and 'Soils as Carbon Sinks', vol. 20. The number of annual citations of articles on N 2 O in the journal has risen from zero in the early 1990s to 160 per year in 2008. In this article, we have highlighted some of the more important papers on N 2 O that have been published by Soil Use and Management, and explain how they have helped advance our understanding of the role that soil management plays in influencing N 2 O emissions.

The Challenge of the Urine Patch for Managing Nitrogen in Grazed Pasture Systems

“…Chamber techniques are less costly and provide reliable measurements in time and space, but do not reliably represent farm or ecosystem scale N 2 O fluxes; here, integrative meteorological techniques become advantageous (Henault et al, 2012). Nitrous oxide emission from grazed pastures have been the focus of much work due to its importance as a greenhouse gas (de Klein et al, 2003;Rees and Ball, 2010), whereas NO and benign N 2 losses have been less well explored (Monaghan and Barraclough, 1993;Skiba et al, 1993;Lovell and Jarvis, 1996). A summary of the literature shows an average N 2 O loss of 2.1% (range 0-14%) of applied urine N (n ¼ 40), from a range of soil types, urine N application rates and seasons (Table 4).…”

Nitrous oxide emissions in agricultural soils: a review

“…Thus, a fixed emission factor does not reflect the effect of the N application rate on N 2 O emissions (Velthof & Mosquera 2011). The use of an emission factor proposed by the IPCC is very simplistic and do not reflect variations in management activities, climate and ecosystems (Rees & Ball 2010). The proposed value does not take into account the soil type and the fact that the climate within a region is not always adequate to describe the spatial and temporal variability of N 2 O emissions (Rees & Ball 2010), as well as the crops to which the fertilizer is applied (Flynn et al 2005).…”

“…The use of an emission factor proposed by the IPCC is very simplistic and do not reflect variations in management activities, climate and ecosystems (Rees & Ball 2010). The proposed value does not take into account the soil type and the fact that the climate within a region is not always adequate to describe the spatial and temporal variability of N 2 O emissions (Rees & Ball 2010), as well as the crops to which the fertilizer is applied (Flynn et al 2005). Although there are not enough longterm datasets to provide the information needed to design emission factors for different climate zones or soil types, the use of specific emission factors that reflect regional variability in climate, soil type and management is a requirement to improve greenhouse gases inventories (Thomson et al 2012).…”

Snow cover manipulation in agricultural fields: as an option for mitigating greenhouse gas emissions

“…However, in agreement with our results of (0.04-2.32 kg N ha À1 year À1 ; Table 1), other researchers have reported relatively smaller values of less than 3 kg N ha À1 year À1 (e.g., Kaiser et al 1998;Koga et al 2004;R ö ver et al 1998;Wagner-Riddle et al 2007). As an N 2 O flux of 3 kg N ha À1 year À1 corresponds to 1.4 Mg CO 2 eq ha À1 year À1 when assuming the coefficient of 298 kg CO 2 eq kg N 2 O (Forster et al 2007), Rees and Ball (2010) proposed that an N 2 O flux of less than 3 kg N ha À1 year À1 may make a small contribution to the total greenhouse gas emissions from an agricultural field, in comparison with the atmospheric C sequestration by crop growth (the net biome production; Randerson et al 2002). Hence, any increased greenhouse gas emissions due to soil frost control would only be of concern if the N 2 O emissions from an agricultural field are in excess of 3 kg N ha À1 year À1 , which would occur in sites with high organic matter or clay soils (e.g., Flessa et al 1995;Koga2013;Maljanen et al 2009;Regina et al 2004;Ruser et al 2001;S y v ä salo et al 2004).…”