Cotton is a Very Thirsty Plant!
Studying How Water Used in Cotton Production Impacts Our Environment.
Out of all the water consumed on Earth, 97% of it is unusable salt water, 2% is frozen and that last 1% is fresh, clean and used for humans, animals and plants alike to thrive. Clean water was once thought of as renewable, but this is rapidly becoming more untrue by the decade.
70% of that 1% of clean water gets used by industry and agriculture
Cotton is one of the main fibre components used in fabric production and is found in almost half of all textiles. The amount of times we encounter cotton in our daily lives is astounding! Cotton is used in our clothing, our linen, our furniture and even our food (cotton-seed oil), however it could be one of the leading factors contributing to the future decline of mankind
To keep up with increasing population sizes, demands and trends, mass production has scaled to terrifying heights and cotton is no exception. On average, 26 million tonnes of cotton are currently produced annually from 90 countries worldwide!
China, the U.S., India, Pakistan, Uzbekistan and West African countries produce just over 80% of these millions of tonnes of cotton.
Aside from our mundane dependence on cotton, this thirsty crop fuels a multi-billion dollar industry and a large portion of our global economy thrives off of the production of cotton.
How Much Water Does Cotton Need to Grow?
Cotton is a very thirsty plant that grows in warm, dry regions regions of roughly 18-30°C. It needs lots of sunshine and no frost during its 175-225 day production time. During this period, each plant needs at least 500mm of water before the prized ‘boll’ forms and the cotton is ready for harvest. However, this number can increase depending on factors such as exact climate, solar radiation, evaporation and humidity levels.
Between 2010 and 2012, the average area of cotton harvested in the US was ±9.8million acres. Based on the above statistics, the USA alone used on average ±2.45 million litres of water in one year.
This does not include all the rest of the water that goes into the processing of cotton after the crop gets grown.
To put this into perspective for us on the consumer end of the spectrum, 1 cotton shirt can use 2,7L of fresh water on average after being manufactured. 1kg of cotton, such as 1 shirt and 1 pair of denim jeans, can require up to 20,000 litres of water in total to make!
Irrigation in Cotton Production
73% of all global cotton production is carried out using irrigation, as opposed to natural rainfall. To produce the quantity of cotton required to meet our demands, farmers have turned to three main forms of irrigation:
As the name implies, water is gently sprinkled over the land from central sprinklers which get rotated over the land.
Water gets pumped along the ground surface, in furrows on either side of the cotton in rows and forms pools.
A more calculated approach, these can be pipes above or below ground that drip water at a continuous rate.
What all of these methods have in common is inefficient, excess water. The latest statistics from irrigated Australian cotton production indicate that 30% of the water used gets wasted. Although in some countries it can be as much as 60%
Aside from wasting such a precious resource, this excess water is an environmental hazard of note!
Why the Irrigation of Cotton Harms the Environment & Us!
The excess water from the irrigation of cotton does many things to injure the environment. This water tends to run-off the land and take nutrients out of the soil with it, decreasing the fertility of the land.
In combination with the high volume of pesticides used on cotton, this run-off suddenly becomes imbued with all these chemicals. This water can remain in the soil as toxic-ground water or surface and either run-off into rivers or lakes or evaporate to form acid rain. This circulates these chemicals throughout our biosphere, killing aquatic, plant and animal life everywhere. “Land Reclamation” or “repossession” of land for farming, also kills many animals to make way for monoculture (cultivation of one crop on a plot of arable land).
Another impact of irrigation on the environment is that it actually has a carbon footprint and uses power to operate. This contributes to the emission of greenhouse gases like CO2, the destruction of the ozone layer and increased solar radiation. This will increase cotton’s thirst for water as well as deplete water via evaporation. Acid rain also creates radiation trapping clouds to much the same effect.
Sustainable Solutions To The Problem
Now that we are aware that we waste water purely by supporting the cotton industry, what can we do to solve the problem? The two obvious solutions would be to recycle cotton products, looking after them well and to cut back on our personal household water consumption, where possible.
Scientists are also making attempts to solve this global threat to our existence on Earth. The genetic modification of cotton makes it more water efficient, however it’s still dependant on chemicals to function after.
Some methods of controlling water wastage in cotton production include - the technique of cover crops and mulch which retain more moisture in the soil, allowing less water to be utilised; Tilling the land which exposes it less to solar radiation drying it out less and causing less soil erosion; Planting trees on the boundary line which can help to absorb some of the toxic ground water before it reaches a body of water and; Methods to keep water locked inside the land, such as moisture probes13, have helped to significantly reduce the water required for cotton.