DANIEL RADFORD
MEMPHIS, TENNESSEE
Cotton growers across the Southeast know no two seasons are alike, and rainfall has always been one of the most unpredictable variables in cotton production. Periods of drought followed by heavy rainfall are making it difficult for growers to decide when and how much to irrigate. Research published in the Journal of Cotton Science shows irrigation can improve yields in dry years, but excess water during wetter seasons can reduce both yield and profitability.
To support more informed irrigation decisions, tools like the SmartIrrigation CropFit app provide a data driven approach to irrigation management. Developed by George Vellidis at the University of Georgia, CropFit combines multiple crop scheduling models, including cotton, into a single user-friendly platform. The app was made possible through funding from USDA NIFA, with additional support from The Cotton Research and Promotion Program through Cotton Incorporated, which helped develop the original standalone cotton model and expand its capabilities within CropFit. Backed by scientific research, the app helps Southeast growers better understand crop water requirements, improve irrigation efficiency, and protect both yield and fiber quality.
Although cotton is relatively drought-tolerant, it still requires timely moisture to reach its full potential. On average, a cotton crop needs about 18-20 inches of water throughout the growing season to achieve optimal yield. From first square through bloom, consistent moisture is critical for maintaining both yield and fiber quality. However, over irrigation can increase input costs, promote disease pressure, and, in some cases, lower yields. Taking all these factors into account, knowing when to irrigate is more important now than ever.
That is where irrigation scheduling becomes a valuable management tool. Rather than relying on fixed schedules or visual cues, scheduling tools use a science-based approach that accounts for weather conditions, soil type, and crop growth stage. By tracking soil moisture, these tools help growers match water applications with crop demand, improving efficiency by applying the right amount at the right time while avoiding unnecessary use. In fact, advanced irrigation scheduling methods have been shown to reduce water use by more than 50% on average compared to traditional calendar-based programs.
SmartIrrigation CropFit cotton model performance
compared to the UGA Extension Calendar Method
| Year | Cotton App Lint Yield (lb/ac) | Yield Difference
(%) |
Irrigation Water Difference
(%) |
Season Type |
| 1 | 1502 | +10% | -75% | Wet |
| 2 | 1901 | +15% | -40% | Dry |
| 3 | 1616 | +5% | -17% | Wet |
| 4 | 1078 | +20% | -34% | Average |
| 5 | 1339 | +15% | -53% | Average |
Designed specifically for Southeastern cropping systems, CropFit uses a water balance model to track how much water is entering and leaving the soil. The app factors in rainfall, irrigation, and crop water use, also known as evapotranspiration, to estimate available soil moisture. When levels drop below established thresholds, the app provides recommendations on when to irrigate and how much water to apply.
Getting started with CropFit is straightforward. After downloading the app from the Apple App Store or Google Play Store, users create field profiles by dropping pins to create a boundary and entering information such as crop type, planting date, and characteristics of the irrigation system. Soil information is extracted automatically from the NRCS Web Soil Survey using the field boundary, while weather data are retrieved from weather station networks or from Apple Weather.
Accurate data are critical to the app’s performance, particularly when it comes to rainfall. As Vellidis explains, “The app generally performs well or better than scheduling with soil moisture sensors but only if rain data are accurate.” He encourages growers to use an automated rain gauge or manually enter rainfall measurements using a plastic rain gauge to ensure reliable recommendations.
Once set up, the app runs continuously, updating recommendations as soil and weather conditions change. Notifications alert users when soil moisture drops below thresholds, helping remove guesswork from irrigation decisions and ensuring they are based on current crop conditions. The app also tracks growing degree days and accurately forecasts cotton’s growth stage.
While designed for irrigation scheduling, many growers are finding additional value in the app’s features. Vellidis noted, “I am continuously surprised by the innovative ways growers use the app. For example, they use the growth stage forecast to make other field management decisions and the app’s ability to create NRCS soils maps of fields for soil sampling.” What began as a scheduling tool has evolved into a more comprehensive decision support resource in the field.
Both research trials and on-farm use demonstrate the value of scheduling tools like CropFit. Studies show these technologies can reduce unnecessary water applications while maintaining or improving yields compared to traditional irrigation methods. In multi-year trials, advanced scheduling methods reduced water use by 21% to 94% with an average of 57%, compared with the UGA Extension Calendar Method. For producers facing high fuel, labor, and input costs, these efficiencies can translate into meaningful savings, along with improved nutrient uptake and more uniform crop development.
Cotton Incorporated’s support of tools like CropFit reflects its commitment to providing practical, research-based solutions tailored to cotton producers. By investing in irrigation technologies, The Cotton Research and Promotion Program is helping growers improve efficiency while adapting to increasingly variable weather conditions.
The CropFit app is free to download for Apple and Android devices. Growers can also visit SmartIrrigationApps.org to access setup resources and explore additional irrigation management tools.
As weather variability continues to challenge cotton production across the Southeast, efficient irrigation management is essential. Tools like CropFit provide growers with the information they need to make timely irrigation decisions, helping reduce costs, conserve water, and protect yield potential. In today’s environment where every decision counts, having the right information at the right time can make a significant difference. ∆
DANIEL RADFORD, SOUTHEAST RCM, THE COTTON BOARD