Long-term effects of contrasting tillage on soil organic carbon, nitrous oxide and ammonia emissions in a Mediterranean Vertisol under different crop sequences

Giuseppe Badagliacca; Emilio Benítez; Gaetano Amato; Luigi Badalucco; Dario Giambalvo; Vito Armando Laudicina; Paolo Ruisi

doi:10.1016/j.scitotenv.2017.11.116

Long-term effects of contrasting tillage on soil organic carbon, nitrous oxide and ammonia emissions in a Mediterranean Vertisol under different crop sequences

Sci Total Environ. 2018 Apr 1:619-620:18-27. doi: 10.1016/j.scitotenv.2017.11.116. Epub 2017 Nov 11.

Authors

Giuseppe Badagliacca¹, Emilio Benítez², Gaetano Amato³, Luigi Badalucco³, Dario Giambalvo³, Vito Armando Laudicina⁴, Paolo Ruisi³

Affiliations

¹ Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy; Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Feo di Vito, 89124 ReggioCalabria, Italy.
² Departamento de Protección Ambiental, Consejo Superior de Investigaciones Científicas (CSIC), Estación Experimental del Zaidín (EEZ), Calle Profesor Albareda 1, 18008 Granada, Spain.
³ Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy.
⁴ Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy. Electronic address: vitoarmando.laudicina@unipa.it.

PMID: 29136531
DOI: 10.1016/j.scitotenv.2017.11.116

Abstract

This 2-year study aimed to verify whether the continuous application of no tillage (NT) for over 20years, in comparison with conventional tillage (CT), affects nitrous oxide (N₂O) and ammonia (NH₃) emissions from a Vertisol and, if so, whether such an effect varies with crop sequence (continuous wheat, WW and wheat after faba bean, FW). To shed light on the mechanisms involved in determining N-gas emissions, soil bulk density, water filled pore space (WFPS), some carbon (C) and nitrogen (N) pools, denitrifying enzyme activity (DEA), and nitrous oxide reductase gene abundance (nosZ gene) were also assessed at 0-15 and 15-30cm soil depth. Tillage system had no significant effect on total NH₃ emissions. On average, total N₂O emissions were higher under NT (2.45kgN₂O-Nha^-1) than CT (1.72kgN₂O-Nha^-1), being the differences between the two tillage systems greater in FW than WW. The higher N₂O emissions in NT treatments were ascribed to the increased bulk density, WFPS, and extractable organic C under NT compared to CT, all factors that generally promote the production of N₂O. Moreover, compared to CT, NT enhanced the potential DEA (114 vs 16μgNkg^-1h^-1) and nosZ gene abundance (116 vs 69 copy number mg^-1 dry soil) in the topsoil. Finally, NT compared to CT led to an average annual increase in C stock of 0.70MgCha^-1year^-1. Though NT can increase the amount os soil organic matter so storing CO₂ into soil, some criticisms related to the increase of N₂O emission arise, thereby suggesting the need for defining management strategies to mitigate such a negative effect.

Keywords: Carbon stock; Greenhouse gas emissions; Mediterranean environment; No tillage; Wheat; nosZ gene.