Dealing with a climate-changed, salty world

October 2019

Countries across the globe are facing a future of dwindling fresh water and cultivable land, plus the prospect of social unrest if food supplies collapse. 

   

America's monocultures of herbicide- and insect-resistant GM crops are all heavily dependent on agrichemical inputs and water.  This intensive agriculture is outstripping the water supply, and what water's left is increasingly saline.   

U.S. GM 'answers' are of course what get the press coverage. 

India is aware of the fast-approaching agricultural crisis caused by climate change.  Sea level rise is inevitable: it will swamp low lying areas with ocean water, threatening millions of subsistence farmers across Asia and leading to population displacements on a scale which countries can't accommodate.    

Although trials of naturally salt-tolerant plants are on-going in India, crop scientists there say conventional breeding is "arduous", "just takes too long and the problem is urgent", "we are not prepared".  While work on GM crops stalled in India in 2007 when the government put a moratorium on field testing, policy seems to be shifting.  Hopes are now pinned on GM rice with artificial genes copied from mangrove trees.  With the help of GMOs, India "could eventually be cultivating wastelands and places considered entirely unsuitable"

COMMENT 

India and the biotech industry could be tilting at GM windmills. GM is the most difficult approach to the salty problem because there's no 'gene', nor even a distinct group of genes for salt tolerance. 

Consider that, besides dealing the toxicity of salt inside the cells, salt tolerance involves multiple physiological mechanisms, for example, barriers to salt ingress, membrane 'pumps' to eliminate the salt, and an ability to sequester salt in areas of the cell where it will cause least damage. 

Also, because salt traps water in the soil, the plants don't wilt but still suffer water-deficiency stress. Salt 'tolerance therefore means stress tolerance, and can vary hugely depending on the plant's growth stage (germination, young growth, adult, grain filling etc.). 

Messing with their DNA might just be boosting one salt-tolerance mechanism at the expense of another and adding another layer of stress to what's already there. 

In short, there are no convenient genes for salt tolerance to be identified and copied into crops to overcome this multiplicity of physiological hurdles. 

However, as scientists in China have shown, plants can evolve tolerance to salt.

China seems to have been thinking a bit further ahead than most (in fact, it seemed to start about the same time as climate change was first suspected).  A project to develop salt-resistant rice varieties began there in 1970 after a suitable wild rice species was discovered.  Since then, eight different species of 'sea rice' have been created, and the first salt-resistant rice was grown on a Chinese beach in 2017 proving it will be able to grow in tidal flats and other salty land. 

The value of this rice is obvious for coping with future encroaching sea-water induced by climate change.  However, there's a more immediate use.  Large areas of our planet's land masses are desert.  In the desert, fresh-water is too valuable to be used for cultivation, so much so that in some areas energy-hungry schemes for the desalination of sea water have been developed to support agriculture.   However, changing the crop to suit the water is a more sustainable proposal than changing the water to suit the crop.  Trials of the Chinese sea rice in the deserts of Dubai have achieved yields of up to 7,500 kg/hectare (the global average is 3,000 kg/hectare).

OUR COMMENT 

It took nearly half a century to develop the first sea rice, but with modern (non-GM, non-gene edited) technology and the benefit of DNA analysis, this process can be speeded up without all the risks and uncertainties of an artificially disturbed genome. 

There are other vital avenues we should be moving down.  For example, diversification of crops to include more naturally salt-tolerant varieties (indeed, in 2010, GM Watch already noted that non-GM salt tolerant potatoes, soyabeans and wheat were under development).  Also, regeneration of the soil with organic, chemical-free agriculture to make efficient use of available water; and reversing climate change.   

You can make a good start by supporting local climate change initiatives.  Check them out, for example, Climate Action Network (www.scottishcommunitiescan.org.uk), Stop Climate Chaos (www.stopclimatechaos.scot). 

And don't forget the UK Soil Association (www.soilassociation.org), the European IFOAM (www.ifoam-eu.org), and the worldwide community of Friends of the Earth (www.foe.org). 

SOURCES: 

• As sea levels rise, GMO salt-tolerant crops could address urgent need, NewYork Time, 18.08.15 
• Erin VanDyke, Salt-Resistant Rice Has Been Grown In Desert Using Seawater By Chinese Researchers, https://canadianhomesteading.ca, 5.06.18 
• Crop Selection for Saline Soils, USDA Agricultural Research Service, www.ars.usda.gov 
• "Sea rice": As genetic modification struggles, crossbreeding succeeds, GM Watch 29.10.18 
• Salinity and Agriculture, International Service for Acquisition of Agri-biotech Applications, March 2008 
• Non-GM successes: Salt tolerance, GM Watch, 29.06.10.

Creative Commons Image by 213852 from Pixabay