Why Irrigate Cotton?
The correct amount of water on your cotton crop is essential for producing high yields. Zimmatic® irrigation systems bring a cost effective solution, alleviating risk when the weather isn’t cooperating. They also give you more flexibility when it comes to planting, because your timeline is not as affected by nature.
Proper irrigation management minimizes yield loss due to crop water stress, optimizes yield per unit of water applied and promotes good management practices. The result is a greater return on investment.
Irrigation impacts every stage of growth
From establishment to harvest, effective water management is important at each stage of cotton growth. At TEAM Irrigation, we take into account many factors when designing irrigation systems to meet your specific needs, such as local microclimate, soil type and elevation.
Cotton plant responses to water stress vary depending on the stage of growth at which the stress occurs, the degree of stress, and the length of time the stress is imposed.
The plant aims to establish a balance between carbohydrate supply and demand. Water stress at any stage of growth will affect both the production and distribution of carbohydrates throughout the plant, as well as shortening of fibers. Carbohydrate demands on the plant, primarily made by developing bolls, restrict excessive vegetative growth.
1. Emergence
Adequate moisture at seeding enhances root development to establish healthy uniform stands |
2. Squaring
Avoidance of water-deficit stress beginning at first square is critical in developing adequate plant structure to facilitate yield goals |
3. First White Bloom
Sufficient moisture before the first bloom provides water for pollination processes
and should be at or near field capacity |
4. Peak Bloom
Water use reaches maximum during peak bloom. Frequent irrigation (every 2 days) of small amounts of water (0.20 - 0.25 in) has been shown to be effective |
5. First Open Boll
Control of late season irrigation is essential. Irrigation (by pivot) should continue until 20% of bolls are open (1-2 weeks after first open boll). |
Dnise McWilliams, Department of Extension Plant Sciences, New Mexico State Universitty. LAS Cruces, New Mexico. "Drought Strategies for Cotton
Download Lindsay Zimmatic Brochure - Increasing Cotton Yields through Efficient Irrigation
Water Requirements
Cotton is considered a drought-tolerant crop, yet it responds well to sufficient water. Depending on climate and length of the total growing period, cotton needs 27 to 51 inches (700 to 1300 mm) to meet its water requirements (ETm). In the early vegetative period, crop water requirements equal 10 percent of total. They are high during the flowering period when leaf area is at its maximum – 50 to 60 percent of total.
Monitoring Evapotranspiration
To effectively plan irrigation, growers need to account for evapotranspiration (ET).
Evaporation is the total water use of a crop, including evaporation from the soil and transpiration by the plant. Humidity, solar radiation, wind, as well as crop health and growth stage affect evapotranspiration.
To measure and monitor crop evapotranspiration, access to the following information is needed:
1. A local weather station report that estimates cotton crop ET.
2. A rain gauge placed in each field or group of adjacent fields.
3. A good estimate of the allowable water depletion for the soil (this can be calculated by extension agents and crop consultants).
Irrigation Optimization
To enhance root development, adequate water should be available in the soil at the time of sowing and pre-irrigation is required when stored soil water from pre-season rainfall is not available. In the vegetative period, irrigation may be scheduled when some 60 percent of the available soil water over the first 2.5 ft (0.75m) has been taken up by the crop.
During flowering, depletion of some 70 percent of available soil water will in general check vegetative growth without impairing yields; delayed irrigation during this period may cause excessive flower and square shedding.
During yield formation (boll filling) and ripening, the soil water depletion may increase from 60 percent to higher values as the season progresses, and depending on climate and depth of stored soil water, irrigation can be terminated 4 to 5 weeks before final picking.
References
1 http://www.cottoncrc.org.au/files/
d3d58a2a-dab6-47e6-9584-992
b0096f977/WP3_1.pdf
2 http://www.fao.org/landandwater/aglw/
cropwater/cotton.stm
Conditions vary by location. Talk to TEAM Irrigation for more detailed information.
Download Lindsay Zimmatic Brochure - Increasing Cotton Yields through Efficient Irrigation
Contact Craig Chandler at TEAM Irrigation on 02 6885 5220 to discuss your irrigation needs
www.teamirrigation.com.au
Contact Craig Chandler at TEAM Irrigation on 02 6885 5220 to discuss your irrigation needs
Company Director, Bob Johnson recently visited Nulla Farming in Cunnamulla. TEAM Irrigation constructed 5 lateral move irrigators and one centre pivot on this property several years ago and continue to maintain the equipment. Irrigated land is 2700 acres. 
