Effects of tillage practices on environment, energy, and economy of maize production in Northeast China

CONTEXT: Conservation tillage plays a positive role in restoring degraded cropland in terms of increasing carbon sequestration, improving soil aggregation, and maintaining crop productivity. Assessing the key indicators of environment, energy, and economy under different tillage practices could provide a comprehensive scientific basis to implement low-carbon emission, clean and sustainable agricultural management, especially in the longterm experiment field. OBJECTIVE: Our objectives were: 1) to compare crop production under different long-term tillage practices, 2) to evaluate the carbon footprint (CF), energy budget, and net ecosystem economic benefit (NEEB) of spring maize production under different long-term tillage practices. METHODS: Three tillage practices consisting of conventional tillage with complete removal of residue (CT), moldboard plowing with residue return (MP) and no-tillage with residue return (NT), had been conducted for eight years. Greenhouse gas (GHG) emissions from the soil were measured, and the inputs of raw materials and outputs of crop production were also recorded. CF, energy budget, and NEEB were evaluated for two consecutive growing seasons based on the life cycle assessment (LCA) approach. RESULTS AND CONCLUSIONS: Compared with CT, NT could reduce N2O emissions and absorb more CH4, whereas MP significantly increased CO2 emissions from soil. However, there was no significant difference in maize yield among all treatments. Moreover, NT led to both the lowest GHG emissions from soil (GWPGHG) and agricultural inputs (AIGHG), thus NT decreased CF by approximately 40% compared to CT for maize production. Furthermore, MP and NT decreased 8.4% and 35.7% of the energy inputs owing to lower diesel fuel consumption in comparison with CT, yet there was no significant difference in energy output among different tillage practices. The same was true in NEEB, although MP and NT showed lower investments during maize production. These results indicated NT required the lowest energy and financial investment for the same maize yield. In conclusion, NT could minimize CF and energy inputs while insuring maize production from a long-term perspective. Longterm NT can be implemented in Northeast China and similar agro-eco-regions around the world. SIGNIFICANCE: The findings of our study provide scientific data on the performance of different long-term tillage practices in the environment, energy budget and economic benefits. Meanwhile, it also helps to clarify the role of agricultural systems in achieving carbon neutrality and saving energy.