Tillage and N source influence soil-emitted nitrous oxide in the Alberta Parkland region

Abstract

Lemke, R. L., Izaurralde, R. C., Nyborg, M. and Solberg, E. D. 1999. Tillage and N source influence soil-emitted nitrous oxide in the Alberta Parkland region. Can. J. Soil Sci. 79: 15-24. Zero tillage systems are receiving attention as possible strategies for sequestering atmospheric carbon. This benefit may be offset by increased N 2 O emissions, which have been reported for soils under zero tillage (ZT) compared to those under more intensive tillage (IT). Comparisons of N 2 O emissions from the two systems have been restricted to the growing season, but substantial losses of N 2 O have been reported during spring thaw events in many regions. Inorganic and organic additions of nitrogen and fallowing have also been shown to increase levels of soil-emitted N 2 O. The objectives for this study were: (i) to confirm that losses of N 2 O are higher under ZT than under IT in Alberta Parkland agroecosystems; (ii) to compare the relative influence of urea fertilizer (56 or 100 kg N ha -1 ), field pea residue (dry matter at 5 Mg ha -1 ), sheep manure (dry matter at 40 Mg ha -1 ) additions, and fallow on total N 2 O losses; and (iii) to investigate possible interactions between fertility and tillage treatments. Gas samples were collected using vented soil covers at three sites near Edmonton, Alberta during 1993, 1994, and 1995. Gas samples were analyzed using a gas chromatograph equipped with a 63 Ni electron capture detector. Estimated annual N 2 O loss ranged from 0.1 to 4.0 kg N ha -1 . Emissions during summer were slightly higher, similar, or lower on ZT compared to those under IT, but were consistently lower on ZT plots during spring thaw. Combined estimates (spring plus summer) of N 2 O loss under ZT were equal to or lower than those under IT. Highest overall losses were observed on fallow plots, followed by fertilizer, pea residue, and then either manure or control plots. We conclude that ZT management systems have potential for reducing agricultural greenhouse gas emissions in the Alberta Parkland region. Les émissions durant l'été étaient légèrement supérieures, semblables ou inférieures en semis direct qu'en travail classique, mais au dégel du printemps elles étaient régulièrement moins fortes en SD. Les valeurs combinées (printemps et été) des déperditions en SD étaient, soit semblables soit inférieures à celles obtenues en régime TI. C'est la jachère qui entraînait les déperditions totales les plus fortes, suivie de la fumure minérale, des restes de culture de pois et de, soit l'apport de fumier de mouton ou le traitement témoin. Il ressort de ces observations que le semis direct peut réellement permettre de réduire les émissions de gaz agricoles à effet de serre en Alberta dans la région de la tremblaie boréale.

Soil organic matter, biota and aggregation in temperate and tropical soils - Effects of no-tillage

“…The higher CH 4 -uptake and increased C sequestration, however, do not counterbalance the greater N 2 O-fluxes under NT; this results in an overall negative greenhouse gas balance of 214 kg CO 2 -equivalents·ha -1 ·yr -1 . However, it is evident from the error terms [126] for the (sub)tropical soils and from [13,16,17,25,48,117,158,159,171,174,178,179,199,215] for the temperate soils.…”

A 3‐year field measurement of methane and nitrous oxide emissions from rice paddies in China: Effects of water regime, crop residue, and fertilizer application

“…Incorporation of crop residues provides a source of readily available C and N, which is believed to induce a higher CH 4 release from rice paddies [Denier van der Gon and Neue, 1995;Wang, 1999] and to influence N 2 O emissions [Aulakh et al, 1991;Cochran et al, 1997;Flessa and Beese, 1995;Lemke et al, 1999]. Decomposition of incorporated organic material is the predominant source of methanogenic substrates in early stage of rice growing [Watanabe and Roger, 1985], and CH 4 emission via ebullition during this period contributes significantly to the total emissions of this gas .…”

Towards optimum sampling for regional-scale N2O emission monitoring in Canada

“…For mineral fertilizers Lemke et al (1999) showed enhanced N 2 O emissions for approximately 4 d following fertilization at Ellerslie in 1994; Corre et al (1996) did not observe significant fertilizer-induced emission for several weeks after N inputs until a major rainfall occurred. Obviously, the soil water status at the time of N inputs will largely determine this lag although Müller et al (2002Müller et al ( , 2004) also note that the lag time will differ for specific N 2 O producing processes.…”

“…Clearly there will always be an interaction between the costs of sampling multiple sites and the resources available. However studies such as those of Corre et al (1996) and Lemke et al (1998Lemke et al ( , 1999 demonstrate that multi-year sampling of a range of sites is possible at an intensity required to yield reliable data.…”

“…There are two main methods used for interpolation. The first, and by far the most common, is linear interpolation between measurements on successive days (i.e., the trapezoidal rule) (e.g., Lemke et al 1999;Rochette et al 2000Rochette et al , 2004Röver et al 1998;Van Bochove et al 2000;Webb et al 2004). This method of interpolation has the advantage of simplicity and reproducibility.…”