Soil carbon sequestration and greenhouse gas emission from spring- and fall-applied poultry litter in corn production as simulated with RZWQM2

Authors: YANG, WEI - China Agricultural University; Feng, Gary; Tewolde, Haile; LI, PINFANG - China Agricultural University

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/23/2018
Publication Date: 10/24/2018
Citation: Yang, W., Feng, G.G., Tewolde, H., Li, P. 2018. Soil carbon sequestration and greenhouse gas emission from spring- and fall-applied poultry litter in corn production as simulated with RZWQM2. Journal of Environmental Quality. 209:1285-1293. https://doi.org/10.1016/j.jclepro.2018.10.251.
DOI: https://doi.org/10.1016/j.jclepro.2018.10.251

Interpretive Summary: Poultry litter is a mixture of chicken manure and one of several bedding materials such as wood shavings. It is generated in abundance as a by-product of the poultry production industry in the South and Southeast. Research in the past 15 to 20 years has shown that this by-product is valuable as a fertilizer for crops in the region. However, applying litter to fertilize crops also leads to inevitable greenhouse gas emissions. Carbon dioxide (CO2) and nitrous oxide (N2O) are two important greenhouse gases that are emitted over an extended period from soils that receive litter. How much of the applied litter is lost in the form of these gases and how much of it remains in the soil following its application is not well understood because measuring the emissions of these gases in the field is difficult, time-consuming, and expensive. We used a simulation model developed by USDA-ARS to estimate N2O and CO2 emissions from a corn field that received 9 ton/acre poultry litter every year for three consecutive years. The results showed that approximately 60% of the carbon added in the form of litter was lost over the three-year period, which implies 60% of the applied litter decomposed in the soil and was lost in the form of CO2 gas. This also implies 40% of the litter remained in the soil after the third year, which would be considered substantial if all that litter remained in the soil layer with the most root activity. Only 6% of the total nitrogen (N) applied in the form of litter was lost as N2O, but N is also lost in forms other than N2O. The CO2 and N2O losses were higher by 14 to 16% if the litter was applied in the fall than in the spring. Overall, this simulation study provides basic information on the fate of carbon and nitrogen derived from poultry litter applied to soils of the Southeast that rarely freeze.

Technical Abstract: Poultry litter has increasingly been used in row crop production systems in the southeastern USA, leading to a potential of greater soil C stocks. However, this also leads to a potential of greater greenhouse gas emissions, the long-term impact of which has not been well investigated. A Root Zone Water Quality model (RZWQM2) calibrated with 3 yr field data was used to predict soil CO2 and N2O emissions and gain and loss of litter-derived C in corn (Zea mays L.) production in northern Mississippi USA. The corn field was fertilized with poultry litter (18 Mg ha-1 yr-1) or NO3NH4 (202 kg ha-1 N yr-1) applied in spring or fall. The results showed that yearly CO2 and N2O emission losses from fall litter applied were 16 and 14% higher than spring applied litter (6,890 vs. 5,935 kg C ha-1 yr-1; 32.6 vs. 28.5 kg N ha-1 yr-1), respectively. Simulated CO2 and N2O emissions from soil fertilized with litter were 0.8 and 1.5 times higher than soils fertilized with commercial NH4NO3. The model tested that, applying litter in spring and fall, relative to synthetic fertilizer, increased SOC by 4% (3,566 kg C ha-1) and 2% (1,687 kg C ha-1) over the 3-year, with a rate of 875 kg C ha-1yr-1 (19% of C applied) for two litter applications. Approximately 60% of litter C added was lost over the course of the experiment, with a rate of 7.53 kg C ha-1 d-1, showing that of 40% of C added remained in the soil profile.