International Year of Soils: Paraquat and climate change

Soil: a thin, fragile, essential layerParaquat is used for weed control by farmers around the world and is playing its part to fight and, if necessary, adapt crop production to climate change. 2015 is the UN’s International Year of Soils. The objectives for the Year of Soils include raising awareness and educating society and decision makers about the profound importance of soil; supporting the sustainable management of soil resources and promoting investment; and enhancing the capacity for information gathering and monitoring at national, regional and global levels.

Soil and climate change

One of the main messages of The International Year of Soils, and the focus of this article, is that soils have an essential role in helping to deal with climate change. The Consultative Group on International Agricultural Research (CGIAR) – a partnership of 15 research centres around the world – has estimated that the global food

Year of Soils Main Messages

  • Healthy soils for food production
  • Soils support biodiversity

    Description

    The variety of life in all its forms, levels and combinations. Includes ecosystem diversity, species diversity, and genetic diversity (IUCN, UNEP and WWF, 1991).

    Authoritative On-line References and Resources

    http://earthtrends.wri.org/ EarthTrends is a comprehensive online database, maintained by the World Resources Institute, that focuses on environmental, social, and economic trends. Statistics on biodiversity indicators are available.
  • Soils protect against climate change
  • Soils store and filter water
  • Soil is effectively a non-renewable resource
system is responsible for up to one third of greenhouse gas emissions caused by humans.1,2 These include carbon dioxide, methane and nitrous oxide released from soil. Biological reactions that take place in soil result in huge quantities of carbon being released to the atmosphere. On the other hand, carbon from the air may be locked-up and stored in the soil. Soil, then, plays a key role in the Carbon Cycle, which also involves plants, animals and industry. Soils with increasing levels of organic matter, e.g. resulting from no-till

Description

Also known as conservation tillage or zero tillage is a way of growing crops from year to year without disturbing the soil through tillage ie cultivating the soil usually with tractor-drawn implements.

Authoritative On-line References and Resources

No-till.com:  A portal for on-line information about no-till farming.
practices whereby large amounts of carbon dioxide, which having been removed from the atmosphere by photosynthesis, are sequestered in soil after the decomposition of unharvested parts of crops. Not plowing means that straw, etc. is converted to soil organic matter by microorganisms and not readily oxidised by soil inversion.
Rice cultivation results in huge amounts of methane being released into the atmosphere; and inefficient use of nitrogen fertilizer means that much is wasted in the form of emissions of nitrous oxide. These gases have warming effects of around 30 and 300 times that of carbon dioxide, respectively. More information can be found on the International Year of Soils website.

Paraquat plays its part

Using paraquat for weed control has a number of environmental benefits. These include reducing soil erosion

Description

Displacement of solids (soil, mud, rock and other particles) usually by the agents of currents such as, wind, water, or ice by downward or down-slope movement.

Authoritative On-line References and Resources

http://soilerosion.net/ This site brings together reliable information on soil erosion from a wide range of disciplines and sources. It aims to be the definitive internet source for those wishing to find out more about soil loss and soil conservation.
, conserving water quality, enhancing biodiversity, creating healthy soils and reducing the carbon footprint of cropping systems. These benefits come from paraquat’s soil properties and how it is used to control weeds in conservation tillage

Description

Any tillage and planting system that covers 30 percent or more of the soil surface with crop residue after planting to reduce soil erosion by water.

Authoritative On-line References and Resources

Purdue University-based Conservation Technology Information Centre.
systems such as no-till.
You can read more about how paraquat helps combat and adapt to climate change in the following articles:

Eco-fallow: More crop per drop with paraquat

Ecofallow is a system based on no-till and herbicides to ensure weeds do not deplete the reserves of soil moisture being accumulated during the fallow (uncropped) period between crops. Water is thereby conserved through the rotation to maximise its availability for crop production. Read more ...
Weeds can rob water stored in fallow

Brazil’s no-till boom fights climate change

Paraquat has always played a pivotal role in the development of no-till cropping systems in Brazil. More recently, the contribution no-till farming can make to fighting climate change has been recognized. No-till soils sequester carbon as organic matter and because there are fewer passes over a field by machinery, considerably less fuel is used. Read more ...
No-till drilling into a weed-free seedbed

No-till rice reduces methane emissions

Research in Indonesia using various cultivation and water management regimes showed that no-till systems reduced methane emissions by 43% compared to traditional methods. The researchers concluded that the best option to reduce methane emissions was a no-till system using paraquat to burndown weeds before flooding and transplanting. Read more ...
New varieties of rice are resisting flooding and other climate problems

References

1.  Vermeulen, S J, Campbell, B M and Ingram, J S I (2012). Climate change and food systems. Annual Review of Environment and Resourses, 37, 195–222 2.  Thornton, P (2012). Recalibrating food production in the developing world: global warming will change more than just the climate. CGIAR Research Program on Climate Change, Agriculture and Food Security No. 6

Notes

The brand name of the leading paraquat product is Gramoxone.