Location: Water Management and Systems ResearchTitle: Deficit irrigation impacts on greenhouse gas emissions under drip-fertigated maize in the Great Plains of Colorado
|Del Grosso, Stephen - Steve|
|SCHNARR, CASSANDRA - Boulder County Parks And Open Space|
|SCHIPANSKI, MEAGAN - Colorado State University|
|VON FISCHER, JOE - Colorado State University|
|STUCHINER, EMILY - Colorado State University|
|FONTE, STEVEN - Colorado State University|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2022
Publication Date: 4/18/2022
Citation: Flynn, N.E., Stewart, C.E., Comas, L.H., Del Grosso, S.J., Schnarr, C., Schipanski, M., Von Fischer, J.C., Stuchiner, E.R., Fonte, S.J. 2022. Deficit irrigation impacts on greenhouse gas emissions under drip-fertigated maize in the Great Plains of Colorado. Journal of Environmental Quality. 51(5):877-889. https://doi.org/10.1002/jeq2.20353.
Interpretive Summary: Managing water and greenhouse gas emissions are major resource challenges of farmers in the western United States. Scientists with USDA's Agricultural Research Service and with Colorado State University studied how certain irrigation practices used to conserve water affected greenhouse gas emissions from corn production. Their findings point to the potential for deficit irrigation and drip fertigation to effectively lower greehouse gas emissions.
Technical Abstract: Precise application of water and nitrogen fertilizer can increase crop water productivity and reduce agricultural contributions to greenhouse gas (GHG) emissions. Regulated deficit irrigation (DI) and drip fertigation are efficient practices that control the amount, location, and timing of water and nutrient application, yet few studies have measured GHG emissions under these practices, especially for maize. The objective of this study was to quantify N2O and CO2 emission from DI and full irrigation (FI) within a drip-fertigated maize system in Northeastern, Colorado. During the two growing seasons of measurement, treatments consisted of mild, moderate, and extreme DI treatments and FI. Deficit irrigation was managed based on growth stage so that full evapotranspiration (ET) was met during the yield-sensitive reproductive stage, but less than full crop ET was applied during the late vegetative and maturation growth stages. In the first year of study, mild DI (90% ET) reduced N2O emissions by 50% compared to FI. In the second year of study, moderate DI (69-80% ET) reduced N2O emissions by 15% and extreme DI (54-68% ET) reduced N2O emissions by 40% compared to FI. Only extreme DI in the second year significantly reduced CO2 emissions (by 30%) compared to FI and DI did not decrease yield-scaled emissions. The surface drip fertigation used in this study resulted in total GHG emissions one tenth of sprinkler irrigated maize systems in the literature. This study provides unique data on the effect of DI on GHG emissions and illustrates the potential of DI and drip fertigation to reduce N2O and CO2 emissions in irrigated cropping systems.