A mega-analysis of no-tillage and reduced tillage impacts on crop yields and greenhouse gas emissions

Authors: KASRIJA, LOVISH - Tennessee State University; HUI, DAFENG - Tennessee State University; RAY, AVEDANANDA - Tennessee State University; REN, WEI - University Of Connecticut; WANG, LIXIN - Indiana University; Fay, Philip; Smith, Douglas; LI, JIANWEL - Tennessee State University; ILLUKPITIYA, PRABODH - Tennessee State University; TIAN, HANQIN - Boston College

Submitted to: Field Crops Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/27/2025
Publication Date: 10/2/2025
Citation: Kasrija, L., Hui, D., Ray, A., Ren, W., Wang, L., Fay, P.A., Smith, D.R., Li, J., Illukpitiya, P., Tian, H. 2025. A mega-analysis of no-tillage and reduced tillage impacts on crop yields and greenhouse gas emissions. Field Crops Research. https://doi.org/10.1016/j.fcr.2025.110167.
DOI: https://doi.org/10.1016/j.fcr.2025.110167

Interpretive Summary: Agriculture has been identified as a contributor to greenhouse gas emissions, including carbon dioxide, methane and nitrous oxide. Conservation tillage practices, including no-tillage and reduced tillage, are thought to be climate-smart strategies to minimize greenhouse gas emissions while maintaining crop yield. To date, meta-analysis of published reports have lead to inclusive results about how these practices affect yield and greenhouse gas losses. In this paper, we evaluate the results of 30 existing meta-analyses to provide a broader overview of how no-tillage and reduced tillage affect greenhouse gas emissions and yield. There is no impact on yield from reduced tillage or reduced tillage combined with no-tillage, but strict no-tillage may decrease yields by roughly 3%. The tillage treatments evaluated here did not significantly affect carbon dioxide or methane emissions, but no-tillage may increase nitrous oxide emissions by more than 8%. This analysis provides a more comprehensive quantification of how tillage systems affect yield and greenhouse gas emissions than previous meta-analyses, which could provide a broader perspective to resource managers and policy makers.

Technical Abstract: Agricultural activities significantly contribute to greenhouse gas (GHG) emissions, accounting for 11% of total emissions, including carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Conservation tillage practices, such as no-tillage (NT) and reduced tillage (RT), are considered climate-smart strategies aimed at mitigating GHG emissions without compromising crop yields. However, existing meta-analyses have produced inconclusive results regarding the effects of these practices on crop yields and soil GHG emissions. To address these inconsistencies, we conducted a mega-analysis, synthesizing data from 30 meta-analyses to provide a comprehensive assessment of the impacts of the NT, RT, and mixed NT+RT on crop yields and GHG emissions. Our results showed that both RT and mixed NT+RT treatments exhibited no significant effect on crop yields, while NT treatment resulted in a 3.3% yield decrease. NT did not influence soil CO2 emissions and none of the tillage treatments (NT, RT, NT+RT) influenced soil CH4 emissions. However, NT treatment increased soil N2O emissions by 8.7%, whereas RT and NT+RT treatment had no significant effect on soil N2O emissions. The varied impacts of tillage treatments were attributed to the interactions between experimental settings (e.g., cropping system, crop type, and experiment duration), soil properties (e.g., soil pH and texture), and other related agriculture practices (e.g., crop residue management, irrigation type, and nitrogen fertilizer application rate). This mega-analysis provides a more comprehensive quantification than individual meta-analyses, offering valuable insights into the impacts of conservation tillage practices on crop yields and GHG emissions.