In the heart of the Mississippi Delta, a two-year study has shed new light on the carbon footprint of cotton production, offering valuable insights for the energy sector and farmers alike. The research, led by Saseendran S. Anapalli of the USDA-ARS Crop Production Systems Research Unit in Stoneville, Mississippi, quantifies the net ecosystem exchange (NEE) of CO2 from cotton fields, providing a benchmark for carbon sequestration potential in cotton production.
Using an eddy covariance approach, the study measured the NEE of CO2 and evapotranspiration from cotton fields on silty clay soil. The findings revealed that on a seasonal scale, NEE was 8,836 kg CO2 ha−1 and 367 mm of evapotranspiration in 2017, and 10,759 kg CO2 ha−1 and 430 mm of evapotranspiration in 2018. Harvested cotton lint yields were 1,269 kg ha−1 in 2017 and 1,569 kg ha−1 in 2018.
One of the most striking findings was the consistency of water use efficiency (WUE) for lint production and ecosystem-level WUE for NEE across the two seasons. “The WUE for lint production was nearly constant, at 3.5 kg lint ha−1 mm−1 in 2017 and 3.6 kg lint ha−1 mm−1 in 2018,” Anapalli noted. “Similarly, the ecosystem-level WUE for NEE was 24 kg CO2 ha−1 mm−1 in 2017 and 25 kg CO2 ha−1 mm−1 in 2018.”
These findings have significant implications for the energy sector, particularly in the development of alternative farm management strategies to enhance carbon sequestration and reduce greenhouse gas emissions. “This research provides a benchmark for comparing carbon sequestration potential in cotton production,” Anapalli explained. “However, further research is needed to understand NEE responses to long-term climate variability and to develop climate-smart crop-soil management strategies.”
The study, published in ‘Agrosystems, Geosciences & Environment’ (which translates to ‘Agricultural Systems, Geosciences & Environment’ in English), highlights the importance of understanding the carbon footprint of agricultural practices. As the energy sector increasingly looks to agriculture for carbon sequestration opportunities, this research offers a valuable starting point for developing more sustainable and efficient farming practices.
The consistency of WUE across the two seasons suggests that cotton production can be a reliable source of carbon sequestration, even in the face of seasonal variations. However, the study also underscores the need for further research to understand the long-term impacts of climate variability on NEE and WUE.
As the energy sector continues to explore opportunities for carbon sequestration, this research provides a crucial benchmark for evaluating the carbon footprint of cotton production. By developing climate-smart crop-soil management strategies, farmers and energy sector professionals can work together to enhance carbon sequestration and reduce greenhouse gas emissions, contributing to a more sustainable future for all.