Sunday February 23, 2020

‘Water management in Rice output key to tackle climate change’

"Improvement in water management will also help in reducing methane emissions and arsenic uptake in the rice fields"

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Rice Crop at it's ripen stage Image Source: Wikimedia Commons
  • Improvement in water management will also help in reducing methane emissions and arsenic uptake in the rice fields
  • De-watering is the practice of removing water from the rice paddies, at least once during the season
  • “Adopting some form of aerobic rice production will also reduce the release of arsenic from soils to groundwater, and the subsequent uptake of arsenic by rice plants.”

At a time when climate change is set to impact rice production in Asia, simple water management by farmers as an adaptation strategy will minimise the damage, an expert said.

“Climate change will impact rice production in large parts of Asia, including India. Water management will be a key feature of decisions aimed at adapting to the impacts of climate change,” Dennis Wichelns, Senior Research Fellow of Thailand-based Stockholm Environment Institute (SEI), said during the Knowledge Forum on Climate Resilient Development in Himalayan and Downstream Regions held in New Delhi recently.

The event was organised jointly by the Ministry of Agriculture and Farmers Welfare, Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) and Delhi-based IEG.

According to Wichelns, improvement in water management will help in areas where higher temperatures are likely and where shift in rainfall pattern is expected.

In certain areas, crop yields will increase in some seasons, perhaps in response to higher rainfall during the production cycle or with a reduction in summer days in the northern regions. In other areas, yields might be reduced due to higher night temperatures, untimely drought conditions, or submergence caused by massive natural events.

According to Wichelns, improvement in water management will also help in reducing methane emissions and arsenic uptake in the rice fields.

“Methane is a potent greenhouse gas. It is estimated that up to 20 per cent of the anthropogenic releases of methane to the atmosphere are generated in agriculture, largely by livestock and in rice production,” he said.

Paddy field in Japan Image Source: Wikimedia Commons
Paddy field in Japan Image Source: Wikimedia Commons

“The anaerobic conditions in which paddy rice is produced is largely responsible for the methane generation and release. Methanogenic organisms, which thrive in anaerobic conditions, break down carbonaceous materials and form methane,” he added.

Efforts to reduce methane generation and release in rice production can substantially reduce greenhouse gas emission from agriculture, thus contributing to climate change mitigation,” Wichelns said.

He said rice production generates substantial amount of methane annually, thus adding notably to the amount of greenhouse gases released into the atmosphere each year.

Switching from flooded paddy production to aerobic rice production or to alternative crops that are produced in aerobic conditions can substantially reduce regional methane emissions, Wichelns added.

Nitrous oxide emissions can increase when switching from anaerobic to aerobic production, yet the change in production methods will reduce global warming potential.

“Adopting some form of aerobic rice production will also reduce the release of arsenic from soils to groundwater, and the subsequent uptake of arsenic by rice plants.” Wichelns said.

Arsenic accumulation in rice grain declines sharply when farmers switch from anaerobic to aerobic production methods. Millions of residents of South and Southeast Asia already are exposed to harmful concentrations of arsenic in drinking water. In those areas, and elsewhere, successful efforts to reduce arsenic uptake in rice will be helpful in reducing total exposure, to the benefit of many adults and children who currently consume harmful amounts of arsenic each day, he said.

De-watering is the practice of removing water from the rice paddies, at least once during the season. Normally, paddies are kept flooded for the entire season, from planting to about two weeks ahead of harvest. Substantial methane is generated and released during that time.

“If farmers remove the water for seven to 10 days mid-season, they can substantially reduce methane generation and release. The paddies are re-watered after the de-watering, but the methanogenic organisms will have been greatly reduced during those seven to 10 days,” Wichelns stressed.

The practice allows oxygen to reach the root zone. The oxygen is unfavourable to the methanogenic organisms, yet favourable to rice roots and thus rice productivity. Therefore, the de-watering also contributes to producing more resilient rice plants with stronger root systems, he added.

Much of the rice production in South and Southeast Asia is found in the deltas formed by major rivers, such as the Mekong, Irrawaddy, and Ganges-Brahmaputra. Rice is well-adapted to these deltaic regions, many of which are characterised by monsoonal climates.

“Given the important role of rice production in rural economies across much of Asia, adaptation strategies are needed urgently to ensure that smallholder farmers can continue producing rice for domestic and international markets, while generating sufficient income and ensuring that household and national food security goals are achieved.” he said. (Source: IANS)

(Imran Khan can be contacted at imran.k@ians.in)

ALSO READ:

  • AJ Krish

    Such methods to reduce methane emissions must be made aware to the farmers. If it is followed in the entire country, the green-house gas emissions can be reduced.

  • Vrushali Mahajan

    Farmers should be informed about the various ways in which water management can be done in their farms. This can help many people retaining water and use it for other purposes.

SHARE
  • AJ Krish

    Such methods to reduce methane emissions must be made aware to the farmers. If it is followed in the entire country, the green-house gas emissions can be reduced.

  • Vrushali Mahajan

    Farmers should be informed about the various ways in which water management can be done in their farms. This can help many people retaining water and use it for other purposes.

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Exposure to Ground Level Ozone Increases Risk of Death

Daily exposure to ozone pollution ups mortality risk

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Ozone
Researchers have found that daily exposure to ground level ozone in cities worldwide is associated with an increased risk of death. Pixabay

Researchers have found that daily exposure to ground level ozone in cities worldwide is associated with an increased risk of death. This is the latest health news.

Ground level ozone is a highly reactive gas commonly found in urban and suburban environments, formed when pollutants react in sunlight.

The findings, published in the journal The BMJ, based on data from over 400 cities in 20 countries across the world – show that more than 6,000 deaths each year would have been avoided in the selected cities if countries had implemented stricter air quality standards.

Ozone
What’s more, smaller but still substantial mortality impacts were found even for ozone concentrations below WHO guideline levels. Pixabay

“These findings have important implications for the design of future public health actions; particularly, for example, in relation to the implementation of mitigation strategies to reduce the impacts of climate change,” said researchers from University of Bern in Switzerland.

Current air quality thresholds (in micrograms per cubic meter of ambient air) range from 100 µg/m3 (WHO), 120 µg/m3 (European Union directive), 140 µg/m3 (US National Ambient Air Quality Standard), and 160 µg/m3 (Chinese Ambient Air Quality Standard).

Recent reviews suggest that 80 per cent of the world’s population in urban areas are exposed to air pollution levels above the WHO threshold.

Most previous studies have found positive associations between ground level ozone and mortality, but differences in study design and quality make it difficult to draw consistent conclusions across different regions.

Ozone
Ground level ozone is a highly reactive gas commonly found in urban and suburban environments, formed when pollutants react in sunlight. Pixabay

To try and address this, an international research team has analysed deaths and environmental measures (weather and air pollutants) in 406 cities of 20 countries, with overlapping periods between 1985 and 2015.

Using data from the Multi-City Multi-Country Collaborative Research Network, they derived daily average ozone levels (above a maximum background level of 70 µg/m3), particulate matter, temperature, and relative humidity at each location to estimate the daily number of extra deaths attributable to ozone. A total of 45,165,171 deaths were analysed in the 406 cities. On average, a 10 µg/m3 increase in ozone during the current and previous day was associated with a 0.18 per cent increased risk of death, suggesting evidence of a potential direct association.

This equates to 6,262 extra deaths each year (or 0.2 per cent of total mortality) in the 406 cities that could potentially have been avoided if countries had implemented stricter air quality standards in line with the WHO guideline.

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What’s more, smaller but still substantial mortality impacts were found even for ozone concentrations below WHO guideline levels, supporting the WHO initiative of encouraging countries to revisit the current air quality guidelines and enforcing stronger emission restrictions to meet these recommendations, say the researchers. (IANS)