The replacement of mineral fertilizers with chicken manure biochar significantly decreases the carbon footprint of wheat

Kazan Federal University, Institute of Environmental Sciences, Kazan, 420008, Russian Federation

^* Corresponding author: goolnaz0708@gmail.com

Abstract

Biochar is a product of oxygen-free thermal decomposition of biomass and refers alternative fertilizers. Data on the carbon footprint of agricultural products obtained using different types of biochars are not enough to date. The purpose of this study was to compare the carbon footprint of wheat of the grade "Yoldyz-Elita", grown using mineral fertilizers "Diamofoska" and biochar. Biochar was received from chicken manure, the pyrolysis process was at 400ºC, for 2 hours. Biochar was added in an amount of 30 t/ha, mineral fertilizers "Diamofoska" in an amount of 300 kg/ha, respectively. Calculations the carbon footprint included data on fuel consumption and N₂O emission from mineral fertilizers, CO₂ emission from soil (respiration activity), data on C fixation in biomass of wheat plants and in biochar. It was demonstrated that the use of biochar led to an increase in total soil carbon by 28% by the end of the field experiment. The application of biochar led to an increase in wheat yield by 2.5 times that was similar to the yield with application of mineral fertilizers. It was found that the main contribution to the carbon footprint of wheat was the respiration activity of the soil (up to 95%). The volume of CO₂ from fuel used by agricultural machinery was insignificant (0.5% of the total CO₂ emissions), soil cultivation with mineral fertilizers increased CO₂ emissions by 3%. The use of biochar as an organomineral fertilizer led to a 79% decrease in the carbon footprint of wheat. Thus, biochar from chicken manures may be recommended to reduce the carbon footprint of wheat.