Co-application of biochar and cattle manure counteract positive priming of carbon mineralization in a sandy soil

Abstract

Background: Application of biochar has been suggested as a carbon (C) management strategy to sequester C and enhance soil quality. An incubation study was carried out to investigate the interactive effect of biochar and cattle manure application on mineralization of carbon (C) in a tropical coastal savanna sandy soil. Methods: The soils were amended with three sole levels of cattle manure (0, 13 and 26 tons ha −1) or biochar (0, 20 and 40 tons ha −1) and four combined manure-biochar levels (20 or 40 tons ha −1 biochar plus 13 or 26 tons ha −1 manure) and CO 2 evolution was measured over 56 days incubation period. The soils were analyzed for mineral N (NH 4 +-N and NO 3 −-N) and water extractable organic C, and net N mineralization, and priming effect (PE) values calculated. Results: The cumulative C mineralized increased in the sole manure and biochar amended soils, resulting in 45-125% positive PE. However, co-application of biochar and manure decelerated decomposition of C, probably through adsorption of labile C and net N immobilization, subsequently leading up to negative 35% PE. Conclusions: The results suggest that co-application of biochar and cattle manure can potentially stabilize C in manure amended sandy soils, albeit with a temporary mineral N limitation to plants. (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.