Effect of Biochar on Emission of Greenhouse Gases and Productivity of Cardoon Crop ( Cynara cardunculus L.)

Cardoon could be cropped for agro-environmental, industrial, and pharmaceutical purposes. The aim of this study was to assess the effects of biochar on emissions of nitrous oxide (N 2 O), carbon dioxide (CO 2 ), and methane (CH 4 ), and productivity of cardoon crop. A pot experiment was run outdoors from April to August 2018, with a cardoon plant per pot. The following four treatments, with four replicates each, were applied: control, soil only; mineral, soil amended with mineral fertilizer (2.5 g N m −2 ); biochar, soil amended with biochar (1 kg m −2 ); and mineral+biochar, soil amended with mineral fertilizer (2.5 g N m −2 ) and biochar (1 kg m −2 ). The morphological characteristics and biomass production of cardoon plants were evaluated, and the fluxes of N 2 O, CO 2 and CH 4 were measured by using the closed chamber technique. The application of biochar combined with mineral reduced N 2 O emissions by 36% and global warming potential (GWP) by 26% relative to mineral. However, the cumulative CO 2 and CH 4 emissions as well as yield-scaled GWP were not significantly different among amended soil treatments. Furthermore, the biomass production was increased by 50% by the application of biochar combined with mineral fertilizer relative to mineral. It was concluded that biochar combined with mineral fertilizer is recommended as a pathway mitigation for agro-environmental purposes, because it reduces the global warming potential and could increase the biomass production of cardoon plants.