Land-use type affects N2O production pathways in subtropical acidic soils. (June 2018)

• Record Type: Journal Article
• Authors: Zhang, Yushu; Ding, Hong; Zheng, Xiangzhou; Ren, Xiangyun; Cardenas, Laura; Carswell, Alison; Misselbrook, Tom
• Is Part Of: Environmental pollution. Volume 237(2018)
• Page Start: 237
• Page End: 243
• Publication Date: 2018-06
• Subjects: Nitrous oxide -- Heterotrophic nitrification -- Autotrophic nitrification -- Denitrification -- 15N -- Stable isotope; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2018.02.045
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: The change in land-use from woodland to crop production leads to increased nitrous oxide (N2 O) emissions. An understanding of the main N2 O sources in soils under a particular land can be a useful tool in developing mitigation strategies. To better understand the effect of land-use on N2 O emissions, soils were collected from 5 different land-uses in southeast China: shrub land (SB), eucalyptus plantation (ET), sweet potato farmland (SP), citrus orchard (CO) and vegetable growing farmland (VE). A stable isotope experiment was conducted incubating soils from the different land use types at 60% water holding capacity (WHC), using 15 NH4 NO3 and NH4 15 NO3 to determine the dominant N2 O production pathway for the different land-uses. The average N2 O emission rates for VE, CO and SP were 5.30, 4.23 and 3.36 μg N kg −1 dry soil d −1, greater than for SB and ET at 0.98 and 1.10 μg N kg −1 dry soil d −1, respectively. N2 O production was dominated by heterotrophic nitrification for SB and ET, accounting for 51 and 50% of N2 O emissions, respectively. However, heterotrophic nitrification was negligible (<8%) in SP, CO and VE, where autotrophic nitrification was a primary driver of N2 O production, accounting for 44, 45 and 66% for SP, CO and VE, respectively. Denitrification was also an important pathway of N2 O production across all land-uses, accounting for 35, 35, 49, 52 and 32% for SB, ET, SP, CO and VE respectively. Average N2 O emission rates via autotrophic nitrification, denitrification and heterotrophic nitrification increased significantly with gross nitrification rates, NO3 − contents and C:N ratios respectively, indicating that these were important factors in the N2 O production pathways for these soils. These results contribute to our understanding and ability to predict N2 O emissions from different land-uses in subtropical acidic soils and in developing potential mitigation strategies. Graphical abstract: Contributions of autotrophic nitrification, denitrification and heterotrophic nitrification on N2 O production in soils from different land use. In shrub and eucalypt land, N2 O production were dominated by heterotrophic nitrification whilst it was minimal in SP, CO and VE, which were dominated by autotrophic nitrification. Denitrification was also an important pathway of N2 O production across all land-use types.Image 1 Highlights: Heterotrophic nitrification was a primary driver of N2 O emissions in natural soil. Autotrophic nitrification was a primary driver of N2 O flux in agricultural soil. Denitrification was an important pathway of N2 O production across all types. Abstract : Autotrophic and heterotrophic nitrification have contrasting contributions to N2 O production in natural and agricultural soils.