Using DMPP with cattle manure can mitigate yield-scaled global warming potential under low rainfall conditions

Area of Science:

• Agricultural Science
• Environmental Science
• Soil Science

Background:

• Organic fertilizers reduce carbon footprint but can increase nitrogen losses.
• Climate change alters rainfall patterns, impacting fertilizer management.
• Nitrification inhibitors are key to minimizing environmental side-effects of organic fertilizers.

Purpose of the Study:

• To evaluate the efficacy of 3,4-dimethylpyrazole phosphate (DMPP) in mitigating nitrous oxide (N2O) emissions and nitrate (NO3-) leaching.
• To assess the impact of simulated rainfall on these mitigation effects in maize cultivation.
• To determine the net global warming potential under different management and rainfall scenarios.

Main Methods:

• Lysimeter experiment with maize (Zea mays L.) on sandy soil.
• Application of manure with and without DMPP under simulated rainfall (R+ and R-).
• Monitoring of soil water, N2O emissions, NO3- leaching, and crop yield.

Main Results:

• DMPP effectively inhibited nitrification, reducing topsoil NO3- by 28% and N2O losses by 82%.
• Annual N2O emission factors were 0.07% with DMPP and 0.95% without.
• Dry conditions reduced yield and NUE, while N2O emissions were higher without DMPP and under reduced rainfall (R-).
• NO3- leaching was unaffected by DMPP or rainfall, occurring mainly post-harvest.

Conclusions:

• Dry growing seasons pose risks to crop production and increase greenhouse gas emissions from sandy soils.
• Nitrification inhibitors (DMPP) are strongly recommended to mitigate climate change impacts.
• Effective management strategies are essential for sustainable agriculture with organic fertilizers.