Location: Agroecosystem Management ResearchTitle: Corn residue removal and CO2 emissions
|Rakkar, Manbir - 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: 2/6/2018
Publication Date: N/A
Interpretive Summary: Soil CO2 emissions are mainly governed by residue removal rate, soil microclimatic conditions and related soil properties that impact biological activity and gaseous exchange reactions. Literature review suggests that residue baling may reduce soil C stocks and change soil conditions to alter CO2 emissions whereas residue grazing may impact CO2 emissions due to manure input. Based on our one-year data, residue grazing and baling appear to have no impact on CO2 emission on a daily basis. However, when the daily CO2 emissions are summed to obtain annual CO2 emissions, residue grazing appears to increase the cumulative CO2 emissions in irrigated crop-livestock systems but baling has no effect. Additional research is required to conclusively ascertain the extent to which baling and grazing affect CO2 emissions under different management conditions and climatic zones. These CO2 results explain only one phase of C cycle, examining the net change in soil organic C and emissions of non-CO2 gases will be essential to discern whether systems under residue baling or grazing are a net GHG or sink.
Technical Abstract: Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) are the primary greenhouse gases (GHG) emitted from the soil due to agricultural activities. In the short-term, increases in CO2 emissions indicate increased soil microbial activity. Soil micro-organisms decompose crop residues and release CO2 as by product. The decomposition of crop residues release nutrients into plant available pool. Abundance of microbes also improves soil structure quality by stabilizing aggregates. Thus, increased CO2 emissions (microbial activity) may indicate improved soil health. A balance, however, is needed between CO2 emissions and C stored in soil to maintain environment and soil productivity. This article discusses the impact of corn residue baling and grazing on CO2 emissions. It is important to emphasize that CO2 emissions explains only one phase of C cycle. Measurements of soil C stocks along with non-CO2 emissions are actual determinants of defining whether the system is a GHG sink or source.