Compost vs biochar amendment: a two-year field study evaluating soil C build-up and N dynamics in an organically managed olive crop
- 1.5k Downloads
Background and aims
Despite the high interest in biochar as soil amendment, the number of field studies is still limited, being experiments with perennial crops in arid lands particularly lacking. This study evaluated the application of compost and biochar in a drip-irrigated organic olive crop in a calcareous soil in South-East Spain.
During two consecutive years, changes in soil total organic C (TOC), dissolved organic C (DOC) and water soluble N (WSN), mineral N (NH4 + and NO3 −), N2O emissions, denitrifying enzyme activity (DEA) and number of amoA gen copies were monitored.
Biochar increased TOC compared to the rest of treatments, whereas DOC and WSN significantly increased in plots amended with compost and the compost-biochar mixture. DEA, amoA-encoding genes and N2O emissions were highest with the compost-biochar mixture, but results were not always significant.
Our results show that, in these N-limited and deficit irrigated semi-arid agro-ecosystems, compost amendment has an impact on soil microbiological activity with a link to N availability. Biochar applied alone does not alter the N dynamics, but markedly builds-up soil C. In both cases only during the first year these effects were statistically significant. When applied in combination a synergistic effect was observed and the highest values of DEA, amoA gene copies and N2O emissions were detected.
KeywordsOrganic farming Nitrous oxide Olive mill waste compost Semi-arid
This study was performed under the framework of the EU project FP7 KBBE.2011.1.2–02 FERTIPLUS co-funded by the European Commission, Directorate General for Research & Innovation, within the 7th Framework Programme of RTD, Theme 2-Biotechnologies, Agriculture & Food. ML Cayuela is supported by a “Ramón y Cajal” research contract from the Spanish Ministry of Economy and Competitiveness. The authors are very grateful to Dr Claudio Mondini for revising the manuscript, to Dr. Nunzio Fiorentino and Dr. Jose A. Alburquerque for his help with field work, to Dr. Joris Eekhout for his aid preparing Fig. 1 and to Juan Molina, manager of “SAT Casa Pareja”, for providing the field site.
- Alsina MM, Fanton-Borges AC, Smart DR (2013) Spatiotemporal variation of event related N2O and CH4 emissions during fertigation in a California almond orchard. Ecosphere 4, art1Google Scholar
- EEC/834 (2007) Council Regulation (EEC) No. 834/2007 of 28 June 2007 on organic production and labelling of organic products and repealing Regulation (EEC) No 2092/91. European Commission Art. 43 TECGoogle Scholar
- Fernández-Escobar R, Moreno R, Sánchez-Zamora MA (2004) Nitrogen dynamics in the olive bearing shoot. HortSci 39:1406–1411Google Scholar
- Parkin TB, Venterea RT (2010) USDA-ARS GRACEnet project protocols, chapter 3. Chamber-based trace gas flux measurements. Sampling protocols. Beltsville, MD p, 1–39Google Scholar
- Prommer J, Wanek W, Hofhansl F, Trojan D, Offre P, Urich T, Schleper C, Sassmann S, Kitzler B, Soja G, Hood-Nowotny RC (2014) Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial. PLoS ONE 9, e86388CrossRefPubMedPubMedCentralGoogle Scholar
- Rumpel C, Leifeld J, Santin C, Doerr S (2015) Movement of biochar in the environment. In: Lehmann J, Joseph S (Eds.) Biochar for environmental management. Earthscan, pp. 283–300Google Scholar
- Sánchez-García M, Roig A, Sanchez-Monedero MA, Cayuela ML (2014) Biochar increases soil N2O emissions produced by nitrification-mediated pathways. Front Environ Sci 2Google Scholar
- Schellenberg DL, Alsina MM, Muhammad S, Stockert CM, Wolff MW, Sanden BL, Brown PH, Smart DR (2012) Yield-scaled global warming potential from N2O emissions and CH4 oxidation for almond (Prunus dulcis) irrigated with nitrogen fertilizers on arid land. Agric Ecosyst Environ 155:7–15CrossRefGoogle Scholar
- Sommer SG, Kjellerup V, Kristjansen O (1992) Determination of total ammonium nitrogen in pig and cattle slurry: sample preparation and analysis. Acta Agric Scand B Plant Soil Sci 42:146–151Google Scholar