Greenhouse gas emissions in response to tillage, nitrogen fertilization, and manure application in the tropics

Authors: ALASINRIN, S - University Of Ilorin; SALAKO, F - Federal University Of Agriculture, Abeokuta; BUSARI, M - Federal University Of Agriculture, Abeokuta; Sainju, Upendra; BADMUS, B - Federal University Of Agriculture, Abeokuta; ISIMIKALU, T - University Of Ilorin

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/4/2023
Publication Date: 9/13/2024
Citation: Alasinrin, S.Y., Salako, F.K., Busari, M.A., Sainju, U.M., Badmus, B.S., Isimikalu, T.O. 2024. Greenhouse gas emissions in response to tillage, nitrogen fertilization, and manure application in the tropics. Soil & Tillage Research. 245. https://doi.org/10.1016/j.still.2024.106296.
DOI: https://doi.org/10.1016/j.still.2024.106296

Interpretive Summary: Global warming due to greenhouse gas (GHG) emissions from agricultural operations is impacting the weather pattern, crop production, and peoples' livelihood in the tropical region of Nigeria. Information is needed about how agricultural management affects GHG emissions and what management practices can be used to reduce GHG emissions without compromising crop yield. An ARS researcher from Sidney, MT collaborated with those from the University of Illorin, Nigeria to study the effect of tillage, nitrogen fertilization, and manure application rates on GHG emissions under maize for two growing seasons. They reported that tillage was a major factor impacting GHG emissions compared to nitrogen fertilization and manure application rates. Increased nitrogen fertilization rates increased nitrous oxide emissions, but manure application rates had little effect on GHG emissions. They found that minimum tillage with the recommended nitrogen fertilization rate (120 kg N/ha) can be used to reduce GHG emissions while enhancing maize yield under the tropical conditions in Nigeria. Producers can use this practice to reduce GHG emissions, enhance maize yield, and sustain environmental quality in the tropical conditions of Sub-Saharan Africa.

Technical Abstract: Cultivation of maize (Zea mays L.) can emit significant greenhouse gases (GHGs) due to root respiration, organic matter decomposition, and fertilizer application in a tropical environment. Our objective was to examine the effect of tillage (conventional tillage [CT], minimum tillage [MT], and no-tillage [NT]), N fertilization rate (0, 90, and 120 kg N ha-1), and manure application rate (0, 5, and 10 Mg ha-1) on CO2, N2O, and CH4 emissions under maize in two growing seasons (July-October 2018 and May-August 2019) in southwest Nigeria. We measured CO2, N2O, and CH4 fluxes using the static chamber method and soil temperature and water content weekly, global warming potential (GWP), maize yield, and greenhouse gas intensity (GHGI). The CO2 and N2O fluxes peaked immediately following planting, fertilization, and intense precipitation, with most fluxes concentrated at 2-6 wk after planting. The CH4 flux was taken mostly by soil, with little changes throughout the growing season. Cumulative CO2 flux was greater for CT and MT than NT in 2018 and 2019. Cumulative N2O flux was also greater for CT and MT than NT in 2018 and increased with increased N fertilization rate in both years. Cumulative CH4 flux was greater for MT than CT and NT in 2018 and greater for 90 and 120 than 0 kg N ha-1 in 2019. The GWP was greater for CT than MT and NT in both years and greater for 90 than 0 kg N ha-1 in 2018. Maize yield was greater for MT than CT and NT and increased with increased N fertilization rate in both years. The GHGI varied with tillage, N fertilization rate, manure application rate, and year. The GHG emissions can be reduced and maize yield can be enhanced by using MT with 120 kg N ha-1 in the tropics.