Does Cotton Need Water?

Cotton, one of the most widely cultivated crops globally, requires water for photosynthesis, growth, and high-quality production. Heat causes water evaporation from the soil and transpiration leads to water releasing from cotton leaves. Therefore, depending on soil and climate conditions, cotton needs between 400-600 mm of water from germination to boll formation.

Irrigation mainly ensures that cotton develops strong roots, resists diseases, has improved fiber quality, and provides high yield consistently. Cotton farming requires irrigation particularly in arid regions where annual rainfall is insufficient. Irrigation helps better utilize the soil and makes it easier to grow healthy cotton. Controlled irrigation is beneficial for achieving consistent high quality at harvest. While cotton can’t grow without sufficient water, too much water can also cause stress and loss in the yield. Therefore, different amounts of irrigation are preferred depending on changing climate conditions and the plant's growth stage.

What are the Irrigation Methods in Cotton?

Irrigation methods are generally divided into surface irrigation and pressurized irrigation. Traditional methods like furrow irrigation and border irrigation are classified as surface irrigation techniques. Pressurized irrigation includes modern techniques such as drip irrigation and sprinkler irrigation.

Furrow Irrigation: Involves directing water into ditches created between plant rows. This simple and low-cost method's main issue is water loss. It is suitable for soils with high water retention capacity and slopes of less than 1%. In Turkey, furrow irrigation is used in flat regions like Çukurova, where water source comes from rivers.

Long Basin Irrigation: Water is directed into wide, long, basin-shaped pools created in the field. Water is not pooled in the basins; it seeps into the plants, and excess water is drained away. This method minimizes soil loss and erosion but requires regular maintenance and control. It is suitable for large, flat agricultural areas.

Sprinkler Irrigation: Water is sprayed onto the cotton like rain using pressurized pipes and sprinklers. This ensures even water distribution, but evaporation and wind dispersion prevent efficient water usage.

Drip Irrigation: Filtered water is delivered directly to the plant roots in drops. This prevents water loss from the soil and maintains stable moisture levels around the roots. Drip irrigation can yield up to 50% more compared to other cotton irrigation systems. Although the initial investment cost is high, drip irrigation requires simple automation systems and minimal soil area, making it more labor-efficient and cost-effective. Drip irrigation systems are preferred worldwide to achieve high-yield harvests while using resources efficiently.

When Are the Irrigation Periods for Cotton?

The irrigation periods can differ based on the type of soil where cotton is grown, and the climate's humidity and temperature values. However, the first irrigation, growth period, and mid-season irrigations are generally necessary according to cotton's growth stages. With advancing technology in recent years, farmers can specifically measure soil moisture levels and the plant's needs. They can even prepare irrigation plans by utilizin computer models.

First Irrigation in Cotton

The first irrigation is done before planting in dry soils, to ensure cotton germination. Whereas in places with sufficient soil humidity, the first irrigation is done after planting to encourage germination. In fact, some farmers delay until early season field operations like weed control are completed. However, studies show that delaying the first irrigation reduces yield.

Last Irrigation in Cotton

Deciding when to stop irrigation at the end of the season is difficult and again varies based on different factors. Generally, the last irrigation should be done when cotton bolls begin to crack. In areas at risk of drought, irrigation can be continued for a few weeks after the bolls open.