Mitigation Effect of Farmyard Manure Application on Greenhouse Gas Emissions from Managed Grasslands in Japan

摘要: Applying manure can lead to decrease of chemical nitrogen (N) fertilizer use and increase soil carbon (C) sequestration. The effect application on net ecosystem C balance (NECB), methane (CH4) nitrous oxide (N2O) emissions global warming potential (GWP) was examined at four managed grasslands Andosols in different climatic regions Japan for 3 years. At adjoining plots each site, exchange (NEE) CH4 N2O fluxes were measured by the eddy covariance method dark chamber methods, respectively. Manure decreased N rate plot 65–88 % plot. NECB (= NEE−C applied + harvested C) higher (1.9 ± 0.9 MgC ha−1 year−1) than (−1.8 1.8 year−1), indicating that soils lost C. There no significant difference between (4.3 0.8 4.1 0.6 year−1, respectively). NEE showed more CO2 uptake (−2.4 1.1 (−1.6 0.7 but could compensate shortage NEE. emission close zero, while greater (6.2 3.7 kgN (3.6 3.2 year−1). GWP a negative relationship with (y = −4.45 ln(x) 2.84; R 2 0.85; p < 0.01), year−1 mitigate Japanese grasslands.