The study of carbon budget on field-tobacco ecosystem

Abstract

The carbon balance of the agricultural ecosystem is of great significance for the assessment of the source and sink of the terrestrial ecosystem. In view of the particularity of the growth and management of flue-cured tobacco, the carbon budget of the field-tobacco ecosystem was studied in order to provide the basis for the improvement of tobacco field management and the estimation of agricultural carbon sink. In this study, the carbon budget was observed with single application of chemical fertilizer using the long-term positioning test station for three years from 2015 to 2017. The results showed that the average cumulative biomass of flue-cured tobacco, the average carbon content of tobacco plant, and the cumulative carbon sequestration were (5832.10 ± 537.32) kg hm-2, (42.14 ± 0.05)%, and (2459.25 ± 233.78) kg hm-2, respectively. The ratio of root carbon to plant carbon was higher, with an average of 24.94%. The wet deposition carbon and the dry deposition carbon were 115.32 kg hm-2 and 6.54 kg hm-2 respectively, both accounting for 20.01% of root carbon amount. The total carbon output in growing season was 2464.98 kg hm-2, in which the CO2 emission expenditure accounts for 98.99%, the runoff carbon expenditure 0.76%, and the leaching carbon accounts for 0.25%. The flue-cured tobacco ecosystem was a weak carbon sink to the atmosphere, with a carbon sink of 116.13 kg hm-2. The total amount of carbon sequestration in flue-cured tobacco was relatively lower, whereas its root system had a relatively higher contribution to soil carbon.