Greenhouse gas mitigation in rice-wheat system with leaf color chart-based urea application

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Conventional nitrogen (N) fertilizer application leads to significant N loss and nitrous oxide (N2O) emissions, a potent greenhouse gas (GHG).
• The Leaf Color Chart (LCC) offers a tool for real-time N management, aligning application with crop needs and potentially mitigating GHG emissions.

Purpose of the Study:

• To evaluate the impact of LCC-based urea application versus conventional methods on N2O, methane (CH4), and carbon dioxide (CO2) emissions.
• To assess the effect on the global warming potential (GWP) and carbon fixation within a rice-wheat cropping system.

Main Methods:

• A 1-year study compared LCC-based N application (scores ≤4 for rice, ≤5 for wheat) with conventional fixed-time N splitting.
• Measurements included N2O, CH4, and CO2 emissions, GWP, and total carbon fixed in the soil.
• The study was conducted in the Indo-Gangetic Plains of India, a key rice-wheat production region.

Main Results:

• LCC-based urea application significantly reduced N2O emissions in both rice (16%) and wheat (18%) compared to conventional methods.
• A reduction in CH4 emissions (11%) was also observed in rice with LCC-based application (LCC ≤4).
• LCC-based N application (LCC ≤4) increased total carbon fixed by 13.3% and reduced the overall GWP of the rice-wheat system by 10.5%.

Conclusions:

• LCC-based nitrogen management is an effective strategy for reducing GHG emissions and enhancing carbon sequestration in rice-wheat systems.
• Optimizing N application through LCC guidance can lead to more sustainable agricultural practices and mitigate climate change impacts.