METHANE EMISSIONS IN RICE FARMING

Rice is a staple food and a basic necessity for over 65% of the world’s population. Each year, around 513 million metric tonnes of milled rice are produced, and about 90% of rice is produced and consumed by people in the Asia-Pacific region. Hence, rice plays a very important role in maintaining food security around the world. Although, rice cultivation comes at a very big environmental cost, i.e., a huge amount of methane emissions.

What Is Methane?

Methane (CH₄) is an odourless, colourless, and highly flammable gas that is present in very small quantities in nature. It is a primary constituent of natural gas and is produced abundantly from numerous human activities (anthropogenic emissions), such as coal mining, wastewater treatment, etc., and through various other natural sources. Though present in small quantities in nature, it is still very harmful for the environment and is therefore considered a greenhouse gas.

Methane (CH₄) is produced in abundant quantities through rice cultivation and is a major cause of environmental concern, i.e., global warming. As we all know, global warming has become a huge concern for many years. The cultivation of rice is a major contributor, contributing up to 8% of total agricultural greenhouse gas emissions all over the world. Let’s dive deep into this topic and understand how it works.

Factors Responsible For Methane Emissions In Rice Farms:

1. Anaerobic Environment: A waterlogged field is the basic requirement in rice cultivation and creates an anaerobic or submerged condition with low oxygen in the atmosphere. This sets the stage for the anaerobic decomposition of organisms like bacteria, which results in methane release as a byproduct.
2. Rice Growth: As the rice plant grows, it creates channels in the soil that take methane from the soil into the environment, causing high levels of methane emissions.
3. Use of fertilisers: The use of nitrogen-based fertilisers fastens the growth of methane-rich bacteria, leading to much higher quantities of methane emissions.
4. Rice Fields: It is a primary source of methane emissions because rice cultivation requires continuous flooding of the fields with water, which induces continuous methane production due to low oxygen.

Case Diaries:

1. West Bengal, India: West Bengal is considered to be one of the major rice-producing states in the country. They used to follow the traditional methodologies of rice cultivation, like flooded fields and water logging, which resulted in severe methane emissions of about 850 kg/ha/year due to anaerobic fermentation.

The state deployed alternative wetting and drying (AWD) methods in the fields, which created aerobic conditions in the area, resulting in 40% less methane emissions.

2. California (United States of America): The area was producing up to 600 kg/ha/year of methane emissions, though less than that of Asian countries due to differences in soil types. But still, it had to apply some of the strategies to mitigate these figures.

The state put in many mitigation methods, like developments in the systems of irrigation and fixation of the rice straws within the soil, which brought down methane emissions by 25%.

The Environmental Impact Of Methane Emissions:

Methane is a potent greenhouse gas; it captures heat much faster and more effectively compared to carbon dioxide. Major impacts include:

1. Climate Change: More methane production means higher levels of global warming, resulting in serious climate change concerns such as extreme weather conditions and higher sea levels.
2. Decreased Air Quality: Methane, although not directly responsible, forms ground-level ozone, which lowers the air quality, making it difficult to breathe.
3. Ecosystem Degradation: There definitely will be an impact from the extremes in weather conditions and poor air quality on the ecosystem, as both water and terrestrial environments are involved.

Strategies To Reduce Methane Emissions:

Key strategies that can be used in order to reduce methane emissions from rice farming are:

1. Alternate Wetting and Drying (AWD): It involves alternative wetting and drying of the fields, which will create aerobic conditions in the soil that will reduce methane emissions in the environment.
2. Advanced Drainage: Advanced drainage systems can solve the problem of water logging, leading to a reduction in water levels and less methane outflow.
3. Reduction of Organic Substances: Lowering the usage of organic matter and fertilisers in fields can lead to a lower methane discharge. Practices such as minimising rice straw burning shall be followed.
4. Selection of Rice Varieties: Rice varieties that produce lower amounts of methane or have stronger root systems shall be selected and promoted to reduce methane emissions.
5. Using Soil Amendments: The use of soil amendments such as gypsum and lime must be increased as they structure the soil and reduce methane emissions.
6. Biogas Production: All countries should pursue different practices to convert the rice-field methane emissions into biogas. So that it can be used as an energy resource.

Conclusion:

We can surely see many states and countries that have started incorporating various mitigation strategies into their rice paddies in order to reduce methane emissions. Deploying mitigation strategies has given proven results in various countries in the form of a significant reduction in methane emissions.

Though many regions still prevail around the world that are stuck with traditional rice farming practices, these regions must be taken into consideration, and through the collaborative efforts of farmers and governments, this problem of following traditional rice farming practices can be terminated.

Want to learn more? Contact KG2 Australia; we are here to provide you with the best sustainable farming solutions and strategies, customised as per your farm needs. Let’s connect and contribute to a greener planet.