Monitoring of CO2 emission fluxes and organic C balance in limed sod-podzolic soil in winter rapeseed field

Abstract

Management of carbon sequestration processes is one of the main issues in overcoming soil organic matter degradation in the Polissya zone, especially taking into account climate changes. There is a need to research and develop measures to reduce unproductive losses of CO2 from the soil, which will contribute to the stabilization of the organic carbon content in the soil under intensive agriculture. The goal of the research was to establish the peculiarities of CO2 emission fluxes formation and the balance of organic carbon in sod-podzolic soil on average over the cultivation years of winter rapeseed in short crop rotation at different doses of ameliorants and fertilizers. Research methods: field experiment, laboratory, computational and statistical analysis. According to the research results it was found that during the spring- summer period of cultivation of winter rapeseed cultivation in crop rotation the highest unproductive losses of CO2 from the soil can be traced in the variant without fertilizers. Significant reductions in the average daily emission fluxes of CO2 from the soil and unproductive losses of carbon dioxide were noted with the application of 1.5 doses of CaMg(CO3 )2 against the background of N120P90K120 to 218.5 kg/ha and 3.64 kg/ ha/h, respectively. Improvement of growing conditions in this variant contributes to increased accumulation of CO2 22% in the biomass of winter rapeseed and, accordingly, an increase in the share of crop residues when they are plowed into the soil to 62.8% of the total carbon dioxide emissions into the atmosphere. Taking into account the share of fertilizers and dolomite flour, the share of humus mineralization decreased to 22.6%. It was found that the application of 1.5 doses of CaMg(- CO3 ) 2 against the background of the recommended dose of fertilizer with the incorporation of by-products into the soil stabilizes the organic carbon balance at the level of 0.05 t/ha. Key words: winter rapeseed, CO2 emissions, chemical reclamation, fertilization, organic carbon balance.