Frequently Asked Questions about Irrigation and Water
Answers provided by our expert team of partners.
Rules of Irrigation
Q: How is irrigation monitored, measured, and regulated?
A: Water resources are primarily managed by the Environmental Protection Department (EPD). Water resources are managed sustainably to support the state's economy, protect public health and natural systems, and enhance the quality of life for all citizens."
Q: Do I need a permit to irrigate?
A: No, if the pump at the water point is capable of pumping 100,000 gallons of water per day, a permit from the Environmental Protection Department (EPD) is required to take water.
Soil Moisture Sensors
Q. What are soil moisture sensors?
A. Soil moisture sensors are electronic devices that are installed in the soil profile, usually in the plant’s root zone, and provide the user with information related to the amount of soil moisture available to the plant. The information might be provided in terms of “percent soil water” or could be a measure of soil water tension in “kiloPascals” or “centibars”.
Q. What are the different types of soil moisture sensors?
A. A multitude of commercial sensors exit on the market, and fall into to two primary categories: tensiometric and volumertric (or capacitance). Capacitance probes use special capacitor related sensors to measure the volume of what in the total volume of soil-- a soil parameter called the dielectric permittivity. Tensio metric soil moisture sensors measure "matric water potential" or soil water tension. This is the amount of energy ('suction') that a plant's roots must exert to extract soil water.
Q. how do soil moisture sensors help with waer management?
A. The purpose of a soil moisture sensor is to monitor soil moisutre status, which allows the farmer to prevent plant stress by maintaining soil moisutre at optimal levels . Soil moisture sensors allow you to determine if there is adequate soil moisture for the crop, if the soil is drying or if the soil is very dry.
Q. how do i install a soil moisture sensor?
A. Each sensor or probe type requires an appropriate installation method. In general, soil moisture sensing equipment must be installed in the soil with good sensor to soil contact. If using individual sensors, a hole must be opened to the depth of interest and then the sensor is installed and soil back-filled into the hole using either a soil-water slurry or a soil-only approach. For probes, a hole is opened up deep enough for the entire probe length and to the depth of interest in the soil. Similarly, after the probe is installed, soil is back-filled into the hole using either a soil-water slurry or a soil-only approach. Some probes are now installed with a dry install where the hole is opened to nearly the exact dimensions of the probe which is then pressed into the hole, requiring no back-fill.
Q. can i link my soil moisture sensor to my pivot to irrigate when dry?
A. From what we understand, currently you cannot link your soil moisture sensors to your center pivot to automatically start the pivot based on soil moisture status. Manufacturers certainly offer the ability to read soil moisture sensors through their control panels, but not automatically start a system. Drip irrigation offers this option.
Q. how many sensors should be installed in a field?
A. If your field is highly variable, it would be good to install sensors in 2 to 4 sites in the field to give you information on soil moisture status in the difffent soil zones in the field. If cost is a major factor or if your field has a single, uniform soil (we rarely see this), then you could install a sensor system in a single location in your field.
Smart Irrigation
Q. what is smart irrigation?
A. Smart Irrigation is the right amount of water in the right place at the right time to optimize growth and efficiency. Efficiency refers to the amount of water pumped that is utilized by the crop.
Q. what is irrigation scheduling?
A. Irrigation scheduling is a technique that involves determining how much water is needed and when to apply it to the field to meet crop demands.
Q. what is vri?
A. VRI stands for Variable Rate Irrigation. Most agricultural fields are highly variable, meaning multiple osil types, elevation changes, and non-cropped areas. VRI allows farmers to apply customized rates of water based on indivaual management zones under the pivot according to soil and crop needs. This improves water use efficiency and and decrease run off and nutrient leaching.
Q. what is vfd?
A. VFD stands for Variable Frequency Drive. VFD units control the speed at which an electric motor spins an irrigation pump. It monitors line pressure to keep your line presure at the right level. If you have a center pivot that has an end gun that is controlled over non cropped areas or VRI controls that turn on/off sprinklers, a VFD can help prevent pressure spikes when flow is lessened.
Q. are there smartphone apps that will help me determine when to irrigate?
A. There are several Smart Irrigation app for both iOS and Android for several agricultural crops,. Each app generates irrigation recommendations for it's specific crop according to thei particular characteristics and phenology of that crop. One of the most useful features of the app is the ability to receive notifications when irrigation is needed, rain events are observed in the field, and approaching phenological stages.
Irrigation 101
Q. how do irrigation systems work?
A. Irrigation systems supply supplemental water to plants either by spraying/sprinkling water from above onto plants and soil (overhead irrigation); by dripping water from a tape or tube onto the soil surface adjacent to plants (drip irrigation); or by dripping water from a drip tape that is buried in the plant root zone (subsurface drip irrigation or SDI). Center pivot irrigation systems are a common type of overhead irrigation found widely in the state of Georgia for row-crop ag irrigation.
Q. how do center pivot irrigation systems work?
A. A center pivot system is essentially a large pressurized water supply pipe that mechanically moves in a circular fashion across an ag field. The main pipe is divided into “spans” which are supported by “towers” with drive motors and the pipe is anchored at the center of the circle – hence the name “center pivot” systems. The span pipes, often 14-16 feet above the soil, are fitted with sprinklers either directly in the pipe itself or suspended below the main pipe on “drop hoses” to get the sprinkler closer to the soil and plants. The sprinklers release the water that falls from above and wets the soil and supplies the plant roots. They are powered by electricity or diesel fuel.
Q. how do drip irrigation systems work?
A. With drip irrigation, water is slowly provided to the area adjacent to the roots of the plant, usually by a network of pressurized lateral lines, drip tape or tubing, and finally, drip emitters. Drip irrigation can have the drip tape or tubing on the soil surface or could be buried drip tape in the root zone (subsurface drip irrigation).
Q. how much water do crops use?
A. The amount of water crops use depends on the crop, variety, and growth stage.
Q. when should i irrigate?
A. If irrigating a plant, you would want to irrigate when the soil moisture in the plant's root zone has been used up by the plant such that there isn't enough moisture left to keep the plant growing optimally.
Q. what is the best time of day to irrigate?
A. Nighttime is the best time to irrigate to reduce water loss from evaporation.
Q. where does irrigation water come from?
A. Our irrigation water comes from the ground or from surface water. Ground water comes from aquifers. Surface water comes from lakes, rivers, ponds, streams, etc.
Q. why do we irrigate?
A. Irrigation is the best risk management tool to safeguard against unpredictable rain patterns and drought.
