Long-term continuous cropping reduces greenhouse gas emissions while sustaining crop yields

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Long-term cropping systems impact greenhouse gas (GHG) emissions under dryland conditions.
• Understanding these effects is crucial for sustainable agriculture in regions like the US northern Great Plains.

Purpose of the Study:

• To evaluate the effect of 34-year-old dryland cropping systems on nitrous oxide (N₂O) and methane (CH₄) emissions.
• To assess the greenhouse gas balance (GHGB), crop yield, and yield-scaled GHG balance (YSGB).

Main Methods:

• Compared no-till continuous spring wheat (NTCW), no-till spring wheat-pea (NTWP), and conventional till spring wheat-fallow (CTWF) systems.
• Monitored GHG fluxes using static chambers over two growing seasons (2016-2018).
• Determined soil carbon sequestration rates and crop yields.

Main Results:

• N₂O emissions were higher in NTCW and NTWP post-planting, fertilization, and rainfall compared to CTWF.
• CH₄ emissions were minimal across all systems.
• Positive soil carbon sequestration occurred in NTCW and NTWP, unlike CTWF.
• GHGB was substantially lower for NTCW and NTWP.
• NTWP showed higher crop yields in one season and lower YSGB in both years.

Conclusions:

• No-till systems, particularly NTWP, demonstrate potential for reducing GHG emissions in dryland agriculture.
• NTWP is recommended for its dual benefit of lowering GHG emissions and maintaining crop yields.
• Sustainable dryland farming practices are key for environmental and agricultural productivity.