The Rice Paddy Problem (& Solutions)

SPECIAL EDITION - Guest Writer

When you hear the words “CO2 emission” what do you think of? Fossil fuel combustion? Gasoline-powered vehicles? Manufacturing materials? Deforestation? Well, what about rice paddies? The IPCC (Intergovernmental Panel on Climate Change) has estimated that rice paddies emit a staggering 10%-12% of global methane emissions (60 million metric tons). These paddies also emit Nitrous Oxide.

Incredibly, over half of the world's population depends on rice cultivation. Farming rice is an ancient practice that has been practiced for thousands of years, with its origins tracing back to ancient China.  Interestingly, rice plants contain a tissue called aerenchyma, which transports oxygen from the leaves of the plant to the roots. Because of this unique tissue, the rice plant can survive in flooded conditions. Rice agriculture takes advantage of this unique tissue. Across the world, and predominantly in Asia, people have farmed rice crops using rice paddies, a field of rice which is flooded in order to shield the rice from harmful radiation and to prevent weeds from disrupting the growth of the rice.

At first, flooding the rice paddies seems like the perfect agricultural practice, eliminating some of these key obstacles in growing rice with little energy required. However, it turns out that this practice is actually detrimental to the environment. The flooding of rice paddies leads to the release of two harmful chemicals into the atmosphere: methane and nitrous oxide. Flooding rice paddies cuts off the soil’s oxygen, ideal conditions for methane-producing microbes to thrive. When the paddies are drained, soil microbes go through a process called nitrification and then denitrification which converts nitrogen into nitrous oxide. 

Luckily, there is a solution. Alternate Wetting and Drying (AWD). By periodically introducing oxygen into the soil, the microbes responsible for producing microbes will die. Unfortunately, employing this solution will actually increase nitrous oxide emissions because the nitrous oxide producers thrive in oxygen rich environments. To accommodate for this, farmers would need to optimize water management and fertilizer placement among other things. And remember, YOU can make a difference, just by doing a little bit of volunteer work or supporting companies meant to help our climate, you can help to save our world.