Produce More Crop Per Drop

Optimizing Irrigation Water Use

The primary agricultural irrigation system is the center pivot irrigation system. There are approximately 23,000 center pivot systems throughout the state, primarily below the Falls Line. Drip irrigation is also used in vegetable and orchard production throughout the state. Other less common forms of irrigation include fixed sprinklers and mobile spray guns.

Some of the practices described below, such as remote control and irrigation scheduling, apply to any type of irrigation system. Other practices, such as retrofitting and variable rate irrigation, are more specific to center pivot irrigation.

Enhance on-farm efficiency

Smart Irrigation tools range from simple and free to complex and costly. The best management practices described below are available to farmers in Georgia. Each practice includes a brief description, examples, an estimated cost, and approximate gains in water use efficiency or water savings. Note: water use efficiency refers to the amount of water pumped that is utilized by the crop (more crop per drop), and water savings refers to actual water conserved from reduction in groundwater withdrawal. The estimates below are not necessarily additive as each efficiency and savings scenario is dependent on individual field conditions and management decisions.

RETROFITS

Convert HIGH PRESSURE sprinklers TO LOW PRESSURE

Irrigation Transformation

The Evolution of Efficiency

In the 1970s, farmers began implementing center-pivot irrigation systems, with traditional models using high-pressure impact sprinklers that applied water from the top of the pivot mainline. Converting these systems from high pressure to low pressure, using spray sprinklers on drip hoses, can save significant amounts of water and energy. By applying low-pressure water more directly to the soil surface, low-pressure systems significantly reduce evaporation and wind drift losses.

Today's low-pressure spray sprinklers are designed to spray water droplets evenly across the field. When used in conjunction with a drip hose, these sprinklers help reduce wind drift and evaporation losses by applying water in larger droplets closer to the crop. In contrast, high-pressure impact sprinklers spray water in smaller droplets higher into the air. Additionally, low-pressure spray sprinklers are unique in that they operate at pressures between 10 and 30 pounds per square inch (psi), which results in lower energy consumption.

A center pivot irrigation system with high pressure sprinklers.

A center pivot irrigation sprinkler with low pressure drop-nozzle sprinklers.

Efficiency

The high pressure system has an average efficiency of 60%, due to water losses from evaporation, wind, and drift. Combined with the installation of end-gun controls to keep irrigation inside the field boundary and the repairing of leaks in the system, retrofitting a pivot may increase water use efficiency to 80 - 90%.

ESTIMATED COST

Converting an existing system from high pressure to low pressure costs range from approximately $2,500 to $5,000. Most new center pivot systems are equipped with low pressure drop hose sprinklers.

REMOTE CONTROL

manage irrigation from anywhere

Remote Irrigation Control

monitor irrigation from phone or web

Farmers have spent countless hours and tanks of gas at all times of the day and night driving back and forth to fields to check irrigation systems. With this remote control technology, a farmer can now save time and fuel with the ability to remotely monitor and control irrigation systems from their phone or computer.

This technology controls multiple aspects of the system remotely: turn on, turn off, change direction, set a timer for the system to start, control the end-gun sprinkler with precision by degree, check the position of the system, set the stop for a precise angle, and even speed control variable rate irrigation on certain systems. All systems enabled with this technology are available on a singular dashboard and even connected with some soil moisture sensor systems transmitting real-time data from the field.

This technology is available for both center pivot and drip irrigation systems.

estimated cost

Remote pivot control systems vary by product but generally range from $2,000 - $5,000 per system with an annual subscription fee in the $300 range.

Efficiency

No official studies have been done to approximate the efficiency of remote control technology for irrigation systems. Any increase in efficiency is highly subjective by field and producer. The ability to stop the system at precise angles, control the end-gun by degree, and set automatic timers to start and stop the system take limitations on timing out of irrigation management (e.g. if the farmer is unable to arrive at a system at the precise moment it needs to be stopped).

IRRIGATION SCHEDULING

KNOW WHEN AND HOW MUCH TO IRRIGATE

WHAT IS IRRIGATION SCHEDULING?

analyzing real-time field data to optimize irrigation application decisions

Irrigation scheduling helps determine when to irrigate and how much water to apply.

Irrigation scheduling can optimize plant growth, crop yield, crop quality, nutrient management, root zone health, and irrigation decisions.

Smart Irrigation Apps

Screenshot of the Smart Irrigation App developed by UGA and UF

Smart irrigation apps for iOS and Android are being developed for several different crops. Apps currently available include cotton, soybeans, citrus, strawberries, and avocados. Corn, peaches, and blueberries are in the development/field validation process and will be publicly released in the next few years.

Each app generates irrigation recommendations for a specific crop based on its specific characteristics and phenology. The concept of the smart irrigation app is to maintain a simple range of inputs (that producers can reasonably answer) which are then used to run a soil water balance model based on estimated water losses (evapotranspiration), crop and region specific coefficients (KC), and observed and predicted weather data (from weather stations, the National Weather Data Grid, and more recently, automated rain sensors for some applications (cotton and soybeans).

One of the most useful features of the app is the ability to receive notifications when irrigation is needed, when rainfall events are observed in areas of the field, and when phenological phases are approaching.

DYNAMIC VARIABLE RATE IRRIGATION

AUTOMATE IRRIGATION PRECISELY WITH REAL-TIME FIELD DATA

Dynamic Variable Rate Irrigation (VRI)

Holistic Precision Systems Approach

Dynamic Variable Rate Irrigation is a practice still between research and commercialization. "A tool that will allow us to improve the sustainability, efficiency and profitability of irrigated agricultural systems."

SMART IRRIGATION integration

Dynamic VRI combines many of the above elements into a precision irrigation system that utilizes real-time field data to apply the needed amount of water at the right time in the right location for optimal crop growth and development.

Standard VRI maps are static, meaning that the irrigation management zones and water application rates are uploaded to the irrigation system infrequently. Dynamic VRI enables the farmer to utilize real-time soil moisture data to update water application rates by zone for each irrigation application.

Estimated Cost

Prices for Dynamic VRI, including a complete VRI system with remote upload capabilities, can range from $20,000 to $45,000, depending on the size of the system and the type of VRI. Other costs include a high-density soil moisture sensor network ($10,000 to $15,000). Dynamic VRI is also best suited for in-depth, on-site analysis of soil and conductivity, which can add additional expense. It can also require more time and intensive management by the farmer, crop advisor, or irrigation manager, another factor that must be considered. There are currently commercial versions of this technology that do not include a high-density soil moisture sensor network. More details and comparisons will be provided in the future.

Efficiency

Research conducted in collaboration with the Soil and Water Conservancy has shown that the integration of Dynamic VRI technology can improve water use efficiency by 40% while increasing yields by 5% to 10% compared to traditional irrigation methods.