Abstract:
Anthropogenic emissions of carbon (C) to the atmosphere at higher rates have led to
global warming and climate change. Soil carbon sequestration (SCS) has been recognized
as the process that stores atmospheric C for a long period without escaping back to the
atmosphere. Globally, expanding agricultural lands has come to play a major role in SCS
in the phase of degradation of natural ecosystems like forests by deforestation, fire, etc.
The objective of this study was to evaluate the potential of Biofilm biofertilizer (BFBF)
application in SCS under rice cultivation. Soil stable C was estimated as sequestered soil
C by using organic carbon (Walkley-Black) and oxidizable carbon in the BFBF
application and the farmers’ chemical fertilizer (CF) alone application. Soil samples were
collected from paddy fields in 25 representative locations in several districts of Sri Lanka
in three consecutive seasons: Yala 2018, Maha 2018/19, and Yala 2019. The results
showed that the SCS was significantly (p<0.05) higher in the BFBF practice in every
season. This is due to increased microbial C assimilation in the root zone of soil. The
BFBF practice sequestered 19 t C ha-1 year–1 over farmers’ CF practice, showing an
enormous potential to gain income through soil C trading. There was also an increasing
trend in the paddy grain yield up to ca. 30% under the same practice. Thus, during the
next five years, if the BFBF practice would be implemented island wide, the potential
income from trading C will be ca. 190 billion rupees. In conclusion, the BFBF practice
can be considered as an eco-friendly and economically viable method to replace the
farmers’ current practice of CF alone application.
Keywords: Biofilm biofertilizer, Carbon trading, Rice cultivation, Soil carbon
sequestration
