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Effect of Enhanced Efficiency Fertilizers on Nitrous Oxide Emissions and Crop Yields: A Meta‐analysis
Author(s) -
Thapa Resham,
Chatterjee Amitava,
Awale Rakesh,
McGranahan Devan A.,
Daigh Aaron
Publication year - 2016
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj2016.06.0179
Subject(s) - soil water , agronomy , nitrous oxide , nitrification , chemistry , crop , environmental science , crop residue , nitrogen , soil science , agriculture , biology , organic chemistry , ecology
Core Ideas Effectiveness of EEFs varied greatly with their modes of action, soils, and management factors. NIs, DIs, and CRFs reduced N2O emissions by 38, 30, and 19%, respectively, compared with conventional N fertilizers. NIs increased overall crop yields by 7% compared with conventional N fertilizers. DIs might provide added benefits over NIs in alkaline soils, coarse‐textured soils, and irrigated systems. Enhanced efficiency fertilizers (EEFs) have the potential to reduce N 2 O emissions and improve crop productivity, but the impact of soil and management conditions on their effectiveness is not clear. We conducted a meta‐analysis to evaluate the effectiveness of different EEF types in reducing N 2 O emissions in three cereal production systems: rice ( Oryza sativa L.), corn ( Zea mays L.), and wheat ( Triticum aestivum L.). We also compared EEF efficacy across soil and management conditions for corn and wheat systems. Results showed that the effect of EEFs on N 2 O emissions and crop yields varied greatly with their modes of action, soil types, and management conditions. Nitrification inhibitors (NIs), double inhibitors (DIs: urease plus nitrification inhibitors), and controlled‐release N fertilizers (CRFs) consistently reduced N 2 O emissions compared with conventional N fertilizers across soil and management conditions (grand mean decreases of 38, 30, and 19%, respectively). The DIs more effectively reduced N 2 O emissions in alkaline soils than did NIs, but the trend was reversed in acidic soils. Urease inhibitors also reduced N 2 O emissions compared with conventional N fertilizers in coarse‐textured soils and irrigated systems. Overall crop yields increased by 7% with the addition of NIs alone. Compared with conventional N fertilizers, DIs also increased crop yields in alkaline soils, coarse‐textured soils, and irrigated systems. However, CRFs had no effect on crop yields. Overall, this study suggests that NIs or DIs can reduce N 2 O emissions while improving crop yields. Growers should select EEFs based on their soil and management conditions to maximize their effectiveness.