Agricultural emissions primarily come from methane and nitrous oxide, both potent greenhouse gases released during crop and livestock production and management activities. Methane is released from livestock digestion and manure management, while nitrous oxide is generated from fertilizer use and soil management practices.

Through carbon sequestration, agriculture can help reduce the concentration of greenhouse gases in the atmosphere. The implementation of agroforestry, where trees are planted alongside crops, can sequester large amounts of carbon, effectively removing carbon dioxide from the air. Furthermore, healthy soil management practices such as reducing tillage, incorporating cover crops, and increasing organic matter and subsequently increase the soil's ability to store carbon.

The majority of nitrogen fertilizers are produced using natural gas. As oil and natural gas reserves continue to decline, the cost of producing these fertilizers is expected to rise significantly in the coming decades. Experts predict that, at current rates, these resources will only last for another 50 years, creating a major challenge for global food production. Meanwhile, 70% of global non-renewable resources are currently allocated to transportation, further stressing the demand for these limited resources.

Technologies like electric vehicles (EVs) are already emerging to reduce the strain on oil and gas reserves, helping to address transportation needs. However, when it comes to nitrogen fertilizers, no viable alternative has yet emerged to fully replace the reliance on natural gas.

Nitrous oxide emissions from agriculture arise from both direct and indirect sources:

1. Direct Nitrous oxide Emissions: These emissions occur during microbial processes like nitrification and denitrification in soils, when nitrogen from fertilizers or manure is added to the land. Nitrification involves converting ammonium into nitrites and nitrates, while denitrification converts these nitrates into nitrous oxide, which is released into the atmosphere.

2. Indirect Nitrous oxide Emissions: Indirect emissions result from nitrogen lost from the soil through processes like volatilization, re-deposition, leaching, and runoff. When nitrogen compounds such as ammonia or nitrogen oxidesare released into the air or water, they can eventually be re-deposited into soils, contributing further to nitrogen oxide emissions after microbial activity.

To calculate Nitrous oxide emissions based on nitrogen fertilizer input, we use a general estimate provided by the Intergovernmental Panel on Climate Change (IPCC), which suggests that 1% to 2% of applied nitrogen is emitted as nitrous oxide.

Example Calculation: Let’s assume a farm applies 100 kg of nitrogen fertilizer per hectare:

• Using the 1% emission factor: 100 kg N × 0.01 (1%) = 1 kg N₂O emissions per hectare.
• Using the 2% emission factor: 100 kg N × 0.02 (2%) = 2 kg N₂O emissions per hectare.

1. Direct CO₂ Emissions from Fertilizer Production: The manufacturing process of synthetic fertilizers, particularly nitrogen fertilizers, which typically relies on natural gas as both a feedstock and energy source, produces significant CO₂ emissions. It is estimated that the production of nitrogen fertilizers alone accounts for about 1-2% of global CO₂ emissions.

2. Indirect CO₂ Emissions from Land Use Change: When forests are cleared for agricultural use or when soil is disturbed, carbon that has been stored in biomass and soils is released into the atmosphere as CO₂.

CO₂ Emissions (kg/ha) = (Fertilizer Input (kg/ha)×Emission Factor) + Indirect Emissions from Land Use

1. Fertilizer Input: The amount of nitrogen fertilizer applied per hectare (kg/ha).

2. Indirect Emissions from Land Use: Agricultural expansion and specific land-use changes.