Manure application timing and incorporation effects on ammonia and greenhouse gas emissions in corn

Authors: Sherman, Jessica; Young, Eric; Jokela, William; KIEKE, BURNEY - Marshfield Clinic Research

Submitted to: Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/17/2022
Publication Date: 11/18/2022
Citation: Sherman, J.F., Young, E.O., Jokela, W.E., Kieke, B. 2022. Manure application timing and incorporation effects on ammonia and greenhouse gas emissions in corn. Agronomy. 12(11). Article 1952. https://doi.org/10.3390/agriculture12111952.
DOI: https://doi.org/10.3390/agriculture12111952

Interpretive Summary: Manure provides essential crop nutrients but may contribute to agricultural greenhouse gas emissions. In this experiment, ammonia and greenhouse gases (nitrous oxide, carbon dioxide, and methane) emitted from corn silage plots were compared after liquid dairy manure was applied in the spring and disk-incorporated before corn planting (pre-plant) and later after corn was growing before the rapid N uptake period (sidedress). Injecting manure at pre-plant or sidedress time drastically reduced ammonia emissions compared to surface applications and affected nitrous oxide losses. Nitrous oxide release was larger for injected treatments since more mineral nitrogen remained available in the soil for conversion to nitrate and potential transformation to nitrous oxide. A model based on the data showed that pre-plant had substantially larger nitrous oxide emissions than sidedress. Treatments had little impact on methane or carbon dioxide emissions. Despite larger nitrous oxide emissions, injection may still offer a greater number of agri-environmental benefits over other application methods.

Technical Abstract: Manure application influences ammonia (NH3) and greenhouse gas emissions, however few studies have quantified manure application methods and timing on NH3, nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) fluxes simultaneously. We evaluated surface applied liquid manure application with disk incorporation versus injection on NH3 (dynamic chamber/equilibrium technique), N2O, CO2, and CH4 fluxes (static vented chamber technique) in central Wisconsin corn silage (Zea mays L.) plots during pre-plant (PP) and sidedress (SD) application windows from 2009 to 2011. Manure treatments were PP-injection (PP-Inject) and injection at sidedress time (SD-inject) to growing corn, along with two incorporation times for PP surface application (within 24 hr; PP-1-hr and within 3-days; PP-3-day). Injected treatments had >90% lower NH3 loss compared to surface application both years, with larger losses for PP-3-day and SD-surface. While N2O fluxes were generally low, larger increases after manure application were associated with injection and triggered by soil moisture/temperature changes. Mean CO2 and CH4 were unaffected by manure treatments and influenced more by weather. Overall, injection conserved more available soil N while contributing to modest N2O emission, suggesting liquid dairy manure injection may offer multiple agri-environmental benefits over surface application.