Conserve Water: Swap Cotton for Hemp?
by Warren McLaren, Sydney on 01. 5.07
Such is the call from South Australian leader of the Democrats, Sandra Kanck. And given the vast quantities of cotton irrigation water extracted from the once great, but now dying Murray and Darling river basin, it would seem, at face value, to be a great idea. Only problem being I don’t recall ever seeing any figures that would indicate hemp is radically more water efficient than cotton. Yes, hemp has much going it, like yield has been quoted by various sources as being two to three times greater than cotton, using significantly less synthetic pesticides, while being an ideal rotation crop. But a trawl through my library of hemp books (which generally trip over themselves in their eagerness to list hemp’s positive properties) failed to elicit this water comparison. A government report in the late ‘90s concluded hemp for fibre would be feasible in Australia ... if the costs of retting (separating fibre from stalk) could be reduced. Otherwise hemp would remain roughly a quarter more expensive than cotton. Retting (rotting) uses water to soak the hemp stems. Even if the cost issue could be resolved (steam explosion was suggested as an alternative) the average hemp fibre is about twice as thick as cotton fibres, making it suitable only for medium weight textile products. It should be noted though that, unlike the US, most Australian states have, at least, sanctioned trial hemp crops, to test commercial feasibility. Ecofibre in Queensland remains one of the most active businesses in this area. Via ::ABC Online. (That govt report can be found here in full.)
Pics found at Ecolution.
Irrigation comes to cotton so it can be grown in places that cotton was otherwise not able to be raised in. Possibly to even get two crops a year off the land. THe question may be better posed as can hemp succeed in more marginal lands than can cotton? If so, we ought to be able to have a production system that has both, but uses net less irrigation water.
Hemptown, one of Canada's largest hemp companies, cites hemp as saving over 800 gallons of water per T-Shirt compared to Cotton (this is for a 55% hemp / 45% cotton blend!) and they have WWF and others as their references. It is something i am very interested in both as a 'hempster' and an ecologist. That is a lot of water, if it's true. Also there are all the other benefits a hemp crop has compared to a cotton one: soil protection, ground cover, deep roots, cellulose resource, oil etc so even if it uses the same amount of water for the crop, the overall productivity is still far greater. Steam explosion seems to me a good interim processing technique, but the real value in the long term lies in using the right fiber for the right product. take the burden off cotton to supply 90% of our natural fiber needs and allow several plant fibers do what they are good at. combine cotton, tencel, modal, ingeo, hemp, nettle, coconut, flax etc and all can play their part. x
"THe question may be better posed as can hemp succeed in more marginal lands than can cotton? If so, we ought to be able to have a production system that has both, but uses net less irrigation water."
That's not really the issue here. The Murray Darling Basin is being used to grow two massively water intensive crops; cotton and rice. Australia is, after Antarctica, the driest continent in the world, I believe, which means that huge amounts of water have been diverted from the Murray and Darling rivers to irrigate these water intensive crops. As a result the rivers have been reduced to a fraction of their former glory, which is having some serious ecological effects.
If hemp uses significantly less water, and the government and industry are willing to switch crops, it could be a big step to saving one of the major river systems on the continent. It's not a matter of hemp being a complementary crop grown where cotton won't; cotton shouldn't be in the Murray Darling Basin in the first place.
Recently my boss told me why cotton is always grown in arid regions, which is why it requires such a lot of irrigation. The family of cotton plants actually grows naturally throughout warm regions, but favours wetter climes.
However, if the cotton plant is to be used for fiber, it has to be dry at harvest time. If the cotton plants are too moist the fibers easily rot and turn black, making it unusable for spinning and fabrics. Of course this means that the water used to grow the plant must be pumped into the dry areas.
The benefit of using organic agriculture techniques for cotton relates to the quality of the soil required by organic agriculture. The spongey texture of the organic matter in the soil absorbs more carbon then conventional carbon farming. And of course, the elimination of harsh fertilizers and pesticides is a benefit as well.
Hemp can be grown in a wider range of climates and does require less irrigation. However, the processing of the fiber is more intensive than cotton, and the tactile qualities of the fabric are different and suited for different purposes. I agree with dru that all fibers can play their part. I would also be interested in seeing a well researched comparison, also including the resources used to process the fibers.