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Cotton

Cotton fact file

  • 31 million ha of cotton are grown worldwide
  • 85 countries grow cotton
  • 51% is grown on the Indian sub-continent
  • 90% of US cotton is GM glyphosate tolerant
  • 25 tonnes/ha of soil are eroded each year from the cotton fields of Alabama, USA

Cotton is a fibre which protects the seed of the cotton plant, much as the flesh of an apple protects the pips.

In 1997, GM cotton tolerant to the non-selective herbicide glyphosate was introduced. Although herbicide tolerant cotton has many advantages, it has contributed to enormous increases in the use of glyphosate which is now posing problems by encouraging the development of resistant weeds, which are no longer controlled by this herbicide.

Paraquat can provide the alternative means of effective and sustainable weed control.

Using paraquat in weed control programmes can also address a number of environmental issues concerned with cotton growing including soil erosion and degradation, water contamination by run-off and leaching of agrochemicals, and loss of habitats and effects on biodiversity.

Paraquat is deactivated on contact with the soil meaning that it can be sprayed to burndown weeds before planting a cotton crop without risking damage to that crop or indeed subsequent crops in the rotation. It does not pollute soil or surface waters because it is immobilised and deactivated immediately on contact with soil. Paraquat works well even in cold and rainy weather, unlike most herbicides, making it suitable for early season burndown.

Cotton was the second genetically modified (GM) crop to be introducedCotton was the second genetically modified (GM) crop to be introduced

Broad-spectrum herbicides, led by the introduction of paraquat in the 1960’s, have allowed the adoption and growth of soil cultivation systems that do not rely on controlling weeds by burial from plowing. Abandoning the mouldboard plow in reduced or no-till systems saves cash, time and fuel, improves soil structure, reduces erosion and provides havens for wildlife. 

Although paraquat is a non-selective, broad spectrum herbicide, if small amounts land on leaves there is little or no crop damage because paraquat does not move through plants systemically like glyphosate. So, paraquat can be used for inter-row weed control in cotton to remove weeds growing between the crop rows.