Optimal lime materials for mitigating global warming potential with and without straw application in acidic upland...

Area of Science:

• Agricultural Science
• Soil Science
• Environmental Science

Background:

• Soil acidification and fertility issues are common in upland soils.
• Lime and crop straw are frequently used to amend acidic soils.
• The interaction between lime types and straw on greenhouse gas (GHG) emissions is not well understood.

Purpose of the Study:

• To investigate the effects of different liming materials (Ca(OH)2, CaO, CaCO3) and rice straw on nitrous oxide (N2O) and carbon dioxide (CO2) emissions from acidic red soil.
• To understand the combined impact of liming materials and straw on GHG emissions and global warming potential (GWP).

Main Methods:

• Incubation experiments were conducted using acidic red soil.
• The study assessed individual and combined applications of Ca(OH)2, CaO, CaCO3, and rice straw.
• Emissions of N2O and CO2 were measured, along with soil properties and microbial biomass.

Main Results:

• Liming generally increased N2O emissions, with Ca(OH)2 showing the highest increase. Straw addition alone significantly increased both N2O and CO2 emissions.
• Combined application of lime and straw further elevated N2O emissions. CaCO3 increased CO2 emissions, while CaO and Ca(OH)2 decreased them.
• Straw addition increased global warming potential (GWP). CaO and Ca(OH)2 application reduced GWP, making them more suitable for mitigating GHG emissions compared to CaCO3.

Conclusions:

• The choice of lime material significantly impacts GHG emissions from acidic soils amended with straw.
• CaO and Ca(OH)2 are optimal choices for reducing soil acidification and mitigating GHG emissions, offering a more sustainable agricultural practice.
• Soil carbon, nitrogen, and microbial biomass play crucial roles in N2O emissions, while CO2 emissions are more influenced by the chemical reactions of lime materials.