Cotton is known as one of the thirstiest crops to grow. But, how much water does it take to grow cotton? What is the water use of cotton compared to other crops and textiles? How can the water footprint be reduced? That’s what we are looking at in this article.
What You'll Learn Today
- Cotton Water Requirements
- Why Does Cotton Use So Much Water?
- Best Watering Practices
- Dos & Don’ts When Watering Cotton
- Optimized Cotton Watering Makes A More Efficient Crop!
Cotton Water Requirements
Despite being known as a water-intensive crop, each cotton plant is estimated to need about 10 gallons of water to maximize its yield. This equates to somewhere around 20-30 inches of water for the full season in the right climate.
A full season can extend to up to 180 days, which is much longer than most other annual crops.
The drastic numbers of water use seen in commercial production are due to the crowded growing conditions that cotton thrives in. Between 40,000-45,000 plants are growing in 1 acre!
Individual irrigation needs will depend on rainfall levels and climate in the growing area.
How Much Water Does It Take To Make A Cotton Shirt?
One cotton shirt requires somewhere around 2,700 litres of water. To yield a kilogram (2.2 lbs) of usable cotton it takes around 20,000 litres or 5283 gallons of water. This amount of cotton is only enough for a t-shirt and pair of jeans!
Cotton Water Use Compared To Other Crops
Cotton is known as one of the most water-intensive crops to grow but it’s not too high on the list. It does take more water than most human-grade vegetables. However, things like vineyards, corn, almonds, pastures, rice, and alfalfa all take more water in comparison.
Cotton Water Use Compared To Other Fabrics
Other than cotton, textiles made from natural sources include flax, bamboo, tencel (made from eucalyptus), and hemp. Cotton uses more water than all these other natural fabrics but remains the favorite.
Flax is relatively new but is gaining popularity. Bamboo processing has been exposed as dangerous and has lost ground in the market. Tencel seems to be a great alternative that takes much less land and water than cotton. The same goes for hemp, but it’s not legal to grow in many places.
Despite the higher water use, cotton remains the top dog in the textile industry (here’s how to make cotton yarn in your homestead). It’s a staple crop in many regions and will continue it’s reign until the fashion industry adopts different textiles on a more widespread basis.
Why Does Cotton Use So Much Water?
This is a common question. However, it’s a drought-tolerant plant that can rely mostly on rainwater in the right climates.
In reality, many commercial cotton fields are grown with inefficient irrigation practices. For example, diverting surface water from rivers leads to excessive evaporation. An optimized field creates a much more efficient yield of cotton.
Another inefficient way to irrigate is overhead watering with sprinklers. It causes more evaporation than better irrigation systems like subsurface drip systems.
It’s not nearly as water-intensive as other crops if you consider the lifetime of your cotton material. It lasts much longer than food crops that spoil and only provide one-time nourishment.
Best Watering Practices
Overhead watering with sprinklers creates more evaporation. That leads to less water reaching the plant roots.
Surface drip irrigation is better than overhead watering. It still creates evaporation, especially once the water starts to pool.
Subsurface watering is the best to make watering most efficient. It can also reduce the occurrence of disease and pests due to less water presence on the soil surface.
Infrequent and deep waterings are best to encourage the best root growth and stronger plants, just like any other crop.
Dos & Don’ts When Watering Cotton
Here are a few basic dos and don’ts when it comes to growing cotton.
Do – Mulch Around The Plants
Mulching helps increase water retention in the soil. This makes irrigation more efficient and ensures less need for frequent watering.
Don’t – Underwater Your Crop
Even though cotton is known as water-intensive it doesn’t mean you should underwater your crop to try and make up for it. Drought conditions can drastically affect yield.
Do – Amend Soil To Suit Cotton’s Needs
Cotton prefers deep, sandy and loamy soils with a pH between 5.5-7.5. The soil should be well-draining. It also prefers nutrient-rich soils. To optimize your production, amending your soil to create this environment is necessary.
Don’t – Rely Only On Rainwater
Rainwater may work great for certain parts of the growing season. However, at its peak point in the season, cotton needs more water than most climates can produce. Hoping the rain falls perfectly for the crop’s needs is a good way to ruin your yield.
Do – Tailor Watering Based On Crop Maturity
Peak blooming season is when cotton needs the most water. Your irrigation system must be customizable. It can’t just run on a set schedule throughout the entire growing season.
Most cotton fields don’t irrigate much, if at all, between planting and blooming. Once the blooming starts irrigation needs rise dramatically to the tune of about 0.28 inches per day. Then, it’s time for the plant to dry out, which reduces all need for irrigation.
Optimized Cotton Watering Makes A More Efficient Crop!
The cotton industry gets a bad wrap for using so much water compared to other crops. If better irrigation tactics are used, along with mulching and amending soils, cotton can be much more efficient with its water use!