Assessing impacts of climate change and long-term conservation practices on greenhouse gas emissions and crop growth in continuous corn systems

Authors: CHENG, HAOMIAO - Yangzhou University; YU, QILIN - Yangzhou University; QI, ZHIMING - McGill University - Canada; BUKOVSKY, MELISSA - National Center For Atmospheric Research (NCAR); XUE, LIN - National Center For Atmospheric Research (NCAR); Jin, Virginia; Ma, Liwang; Harmel, Daren; CHEN, XIAOPING - Yangzhou University; JI, SHU - Yangzhou University; MIAO, LINGZHAN - Yangzhou University; FENG, SHAYUAN - Yangzhou University

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/31/2023
Publication Date: N/A
Citation: N/A

Interpretive Summary: The impact of future climate on crop production depends on reliable long-term field measurements. Here, we show twelve different simulations of future climate scenarios on an eastern Nebraska continuous corn production system under irrigation. We found that on average, future climate tended to decrease crop yields by 9% and increase soil nitrous oxide (N2O) emissions by 27%. Slight increases in soil organic carbon (SOC) offset greater N2O emissions, but still resulted in an 20% higher global warming potential compared to historical measurements. Conservation practices were key to building SOC, specifically retaining crop residues and using no-till practices.

Technical Abstract: Understanding the impacts of future climate change-driven and long-term conservation practices on environmental quality and agricultural productivity is critically important to the development of sustainable agronomic managements to address global climate change. However, their potential impacts on greenhouse gas (GHG) emissions and crop growth are poorly documented. In this study, 12 different GCMs-RCMs (global climate models coupled with regional climate models), under representative concentration pathway 8.5 (RCP8.5) and rising CO2 concentration ([CO2]atm=714.1 ppm), were generated to project future climate from 2065 to 2084 for a continuous corn field in Nebraska, USA. The effect of four treatments of long-term conservation practices were simulated under the 12 GCMs-RCMs scenarios by using a well-calibrated Root Zone Water Quality Model (RZWQM2). Averaged across all the treatments, the results showed that temperature, atmospheric carbon dioxide concentration ([CO2]atm), and precipitation had a dominant impact on CO2, nitrous oxide (N2O) emissions, global warming potential (GWP), soil organic carbon (SOC), crop yield, and total biomass. The sum of their relative contribution rates exceeded 83.9%. Compared with the historical climate scenarios, the integrated future climate significantly increased the CO2 and N2O emissions by 19.4%±5.8% and 26.6%±8.9%, respectively. The GWP increased by 19.8±5.8% due to the dominance of CO2 emissions (making up 94.1%±1.9% of the GWP). Although the rising [CO2]atm had limited benefits on the crop photosynthesis rates, the rising temperature shortened crop growth cycles, which resulted in a net decrease of 9.1%±1.9% for crop yield and 4.2%±1.6% for total biomass. The temperature and [CO2]atm had a dominant positive correlation with the SOC, which resulted in a net increase of 4.8%±0.4% under integrated future climate. Among the treatments, the results demonstrated that residue retention and tillage practices increased GHG emissions. The conservation practices (i.e., residue retention and no-till) increased SOC. The yields and biomass were not significantly affected by residue and tillage management practices. Findings of this study have important implications for establishing management practices to alleviate future GHG emissions.