Field Crops Research 135 (2012) 10–21 Contents lists available at SciVerse ScienceDirect Field Crops Research jou rnal h om epage: www.elsevier.com/locate/fcr Review Fertilizer management practices and greenhouse gas emissions from rice systems: A quantitative review and analysis Bruce A. Linquist a,∗ , Maria Arlene Adviento-Borbe a , Cameron M. Pittelkow a , Chris van Kessel a , Kees Jan van Groenigen b,c a Department of Plant Sciences, University of California, Davis, CA 95616, USA b Department of Biological Sciences and Merriam-Powell Center for Environmental Research, Northern Arizona University, Flagstaff, AZ 86011, USA c Department of Botany, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland a r t i c l e i n f o Article history: Received 3 May 2012 Accepted 12 June 2012 Keywords: Inhibitor Manure Meta-analysis Methane Mitigation Nitrogen Nitrous oxide Rice Sulfate a b s t r a c t Flooded rice systems emit both methane (CH 4 ) and nitrous oxide (N 2 O). Elevated CH 4 emissions in rice systems can lead to a high global warming potential (GWP) relative to other crops, thus strategies to reduce greenhouse (GHG) emissions, particularly CH 4 , are needed. Altering water, residue (carbon) and fertilizer management practices are commonly suggested as options for mitigating GHG emissions in rice systems. While the effects of water and residue management have been reported on elsewhere, the impact of fertilizer management on GHG emissions has not been reviewed quantitatively. We conducted an exhaustive search of peer-reviewed field studies that compared various side-by-side fertilizer man- agement options. Where sufficient studies were available a meta-analysis was conducted to determine average treatment effects of management practices on both CH 4 and N 2 O emissions. Results show that low inorganic fertilizer N rates (averaging 79 kg N ha -1 ) increased CH 4 emissions by 18% relative to when no N fertilizer was applied, while high N rates (average of 249 kg N ha -1 ) decreased CH 4 emissions by 15%. Replacing urea with ammonium sulfate at the same N rate significantly reduced CH 4 emissions by 40%, but may increase N 2 O emissions. Overall, the fertilizer-induced emission factor for all inorganic N sources was 0.22%. Dicyandiamide (DCD), a nitrification inhibitor, led to lower emissions of both CH 4 (-18%) and N 2 O (-29%). Limited field data suggest that deep placement of N fertilizer reduces CH 4 emis- sions but increases N 2 O emissions. When compared to inorganic N fertilizers, farmyard manure (FYM) increased CH 4 emissions by 26% and the green manure (GrM) Sesbania by 192%. Neither FYM nor GrM had a significant impact on N 2 O emissions when compared to an inorganic N treatment at the same N rate. Sulfate fertilizers reduced CH 4 emissions by 28% and 53% at average rates of 208 and 992 kg S ha -1 , respectively. These findings demonstrate that a variety of fertilizer management practices affect GHG emissions from rice systems. To develop effective GHG mitigation strategies future work is needed to (i) quantify the effects on GWP (accounting for both CH 4 and N 2 O emissions), (ii) investigate options for combining mitigation practices (e.g. deep placement of ammonium sulfate), and (iii) determine the economic viability of these practices. © 2012 Elsevier B.V. All rights reserved. Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2. Materials and methods .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.1. Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 2.2. Data analysis .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3. Results and discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1. Inorganic N rate and GHG emissions (dataset 1) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.1. CH 4 emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1.2. N 2 O emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 3.2. N source and GHG emissions (dataset 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 ∗ Corresponding author. Tel.: +1 530 752 3125; fax: +1 530 752 4361. E-mail address: balinquist@ucdavis.edu (B.A. Linquist). 0378-4290/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fcr.2012.06.007