Greenhouse gas intensity and net ecosystem carbon budget following the application of green manures in rice paddies

• Published in: Nutrient cycling in agroecosystems 2016-11, Vol.106 (2), p.169-183
• Main Authors: Gao, Xiaoye, Lv, Aimin, Wang, Shengyin, Su, Liantai, Zhou, Peng, An, Yuan
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agriculture; Alfalfa; Beans; Biomedical and Life Sciences; Broad beans; Carbon; Carbon/nitrogen ratio; Crop growth; Crop yield; Ecosystems; Emissions; Fertility; Fertilization; Fertilizers; Grain; Greenhouse effect; Greenhouse gases; Life Sciences; Manures; Medicago sativa; Methane; Nitrous oxide; Original Article; Oryza; Rice; Rice fields; Soil fertility; Soil quality; Soil temperature; Soils; Vicia faba
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-016-9797-7

Green manure application has been a good fertility management for crop growth and soil quality, but its effect on greenhouse gas intensity ( GHGI ) and net ecosystem carbon budget ( NECB ) of rice ecosystem is not well understood. Two green manure species, alfalfa ( Medicago sativa L.) and broad beans ( Vicia faba L.), and two N fertilization levels (0 and 200 kg ha −1 ), alone or in combination, were applied to rice paddy soils in 2012 and 2013. The results show that the grain yields increased by 25.36, 29.81, and 41.85 % for the N fertilizer, N + broad bean, and N + alfalfa treatments, respectively, compared with the no fertilizer. CH 4 and N 2 O emissions increased by 50.77 and 36.11 %, 30.70 and 75.04 % in N + broad bean and N + alfalfa treatments, respectively, compared to N fertilizer treatment. The average CH 4 and N 2 O emissions were 37.47 and 63.22 % higher in 2013 than in 2012, respectively, whereas the average soil temperature during the rice growth period was 2.1 °C higher in 2013 than in 2012. The highest value in GHGI was associated with the N + broad bean treatment (with a high C/N ratio), while the NECB and mass of soil total carbon change ( MSTC) were highest in the N + alfalfa treatment (with a low C/N ratio). This result indicates that high C/N ratio green manures had high grain yields yet increased GHGI , while low C/N ratio green manures had even higher grains yields with increased NECB and MSTC .