Hi there! Hope you are having a great week so far. Today, we would be discussing the emission of greenhouse gases due to rice farming and potential solutions to improve the problem.
Rice is a staple in most Southeast Asian countries. Personally, I won’t be able to go a day without having rice in at least one of my meals. Unfortunately, our beloved rice is actually a major contributor of greenhouse gases, contributing to global climate change.
Rice paddies produce large amounts of Methane (CH4) and Nitrous Dioxide (NO2), both potent and persistent greenhouse gases. Global rice farming is estimated to produce 20-40 Tg/yr of Methane, accounting for 10-20% of the global anthropogenic emissions of methane (CH4) (Li et al., 2018). On the other hand, rice cultivation also emits nitrous oxide (N20), at an estimated rate of 32 Gg N2O-N yr−1 (Li et al., 2018).
Methane is produced by the anaerobic decomposition of organic material in flooded rice fields, the gas then escapes to the atmosphere through the rice plants (IPCC, 1996). Nitrous Dioxide is produced by soil microorganisms and the rice plants act as a channel, emitting them into the atmosphere (Timilsina et al., 2020).
According to Li et al. (2018) study, the use of the Water Saving Irrigation Technique as opposed to conventional irrigation which is characterised by leaving the rice field continuously flooded reduces Methane production. The Water-Saving Irrigation method involves alternating flooding and draining the fields depending on the stage of the rice plant. This method is found to reduce Methane emissions by over 30% while providing a similar rice yield (Li et al., 2018).
The same study also found that the use of Modified Nitrogen fertilisers such as controlled release Urea (CRU), Uresase inhibitor (UI) has the potential to reduce N20 emissions (Li et al., 2018). When compared to conventional fertilisers, the modified nitrogen fertilisers produces 18-34% lesser Nitrogen Dioxide emissions (Li et al., 2018).
Hope you learned something from this week’s blog post. Stay tuned for more articles about food pollution.
References
Li, J., Li, Y., Wan, Y., Wang, B., Waqas, M. A., Cai, W., Guo, C., Zhou, S., Su, R., Qin, X., Gao, Q., & Wilkes, A. (2018). Combination of modified nitrogen fertilizers and water saving irrigation can reduce greenhouse gas emissions and increase rice yield. Geoderma, 315, 1-10. https://doi.org/10.1016/j.geoderma.2017.11.033
IPCC. (1996). Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories. Retrieved on March 6, 2022 from https://www.ipcc-nggip.iges.or.jp/public/gl/guidelin/ch4ref5.pdf
Timilsina, A., Bizimana, F., Pandey, B., Yadav, R. K. P., Dong, W., & Hu, C. (2020). Nitrous oxide emissions from paddies: Understanding the role of rice plants. Plants (Basel), 9(2), 180. https://doi.org/10.3390/plants9020180
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