55% of Indian large rice fields could face yield loss due to high carbon dioxide content in the atmosphere

Just the fact that you're reading this article means you probably reside in some type of urban setting. This also means that on many days, you find yourself torn, choosing to stick to the staple rice or treating yourself to something slightly more extravagant for the next meal.

Unfortunately, this is hardly the case for the impoverished in India, many of who resort to meals like plainamak-bhat (cooked rice with plain salt) to pull them out of starvation. India's Public Distribution System helps provide them with grains for the month, but even that falls short oftentimes.

With millions of Indians devastatingly reliant on rice as their staple food, it is imperative that we maintain our crop yields to ensure adequate supply to every sect of society. However, a new report has shown that excessive atmospheric carbon dioxide levels could affect rice yields significantly in low- and middle-income countries, including India and China.

A study published in the journal Nature Geoscience has shown that high atmospheric CO2 levels can reduce phosphorus availability in soils by more than 20% in rice fields. Since phosphorus is an essential fertiliser for the crop, this could substantially affect final yields.

How substantially? By as much as 55%, it turns out. The research has pinpointed that over half of large rice paddy fields in India and China could experience an increased risk of yield reduction due to this phosphorus deficiency.

This isn't the worst of it either; other low-income countries in Southeast Asia, Central America, Africa and the Middle East could see even riskier percentages, going up as high as 70% in some places.

Atmospheric CO2 is actually an excellent source of carbon for crops, which helps increase them photosynthesise more, improving plant growth, biomass and yield. However, the study revealed that this was actually a double-edged sword, since its long-term presence impoverishes the soil of phosphorous.

Furthermore, phosphorus as a chemical fertiliser is unevenly distributed worldwide, making its import exceedingly valuable to countries without the resource. India is a prime example, with the country 90% dependent on rock phosphate as the key raw material in DAP and NPK fertilisers. In the past, phosphorus import prices have skyrocketed during food crises, which can severely exacerbate the food security of countries with inadequate purchasing powers.

Date: 17-Mar-2023