Location: Agroecosystem Management ResearchTitle: Cover crop and CO2 emissions
|RUIS, SABRINA - University Of Nebraska|
|BLANCO, HUMBERTO - University Of Nebraska|
|WORTMANN, CHARLES - University Of Nebraska|
|WILLIAMS, TYLER - University Of Nebraska|
Submitted to: Extension Publications
Publication Type: Experiment Station
Publication Acceptance Date: 2/26/2018
Publication Date: N/A
Interpretive Summary: Cover crops terminated when relatively small (less than 2 t ac-1 of biomass yield) appear not to affect CO2 emissions in an ongoing study in eastern Nebraska. However, late-terminated cover crops with higher biomass production can increase CO2 emissions most likely due to plant respiration. Based on the results of our Nebraska study, termination time of cover crops can affect CO2 emissions on a short-term basis compared to early-terminated cover crops or no cover crop. While cover crops can increase SOC, reduce erosion risks, and reduce nutrient loss, in the C-rich soils of this study, cover crops did not significantly impact SOC or CO2 emissions. Overall, our study showed that cover crop effects on CO2 emissions are linked to cover crop biomass production and are generally confined to the cover crop growing period.
Technical Abstract: Agricultural land management practices account for about 50% of soil organic carbon (SOC) loss. Restoring SOC is important to soil productivity and fertility. Management strategies to rebuild SOC include addition of manure or other organic amendments, increasing root biomass from crops, leaving crop residues on the field, reducing soil disturbance, and using cover crops. Using cover crops during fallow seasons is an opportunity to build SOC through added input of fresh residue C into the soil. The input of fresh organic matter from cover crops may enhance soil biological activity and other soil processes, which can contribute to the decomposition of aboveground and belowground biomass. The decomposition of organic matter occurs through microbial activities and results in emission of CO2 from the soil. Stimulation of biological activity due to microbial activity could result in increased CO2 emissions and losses of SOC. One question regarding cover crop effects on SOC dynamics and storage is: Does the use of cover crops alter net carbon dioxide (CO2) emissions from the soil?