Soil Moisture Based Irrigation Scheduling

Soil Moisture Based Irrigation Scheduling

An analysis of soil moisture readings is a good way to determine when and how much to irrigate no matter what the crop or irrigation method. Irrigation scheduling through soil moisture analysis improves efficiency and can lead to improved quality, yield, and profits.

Soil moisture monitoring provides detailed information about the changing soil moisture status, indicating when crops are at risk for stress, when to irrigate, and when to stop. Soil moisture data reveals the wetting front as water moves down through the root zone. By irrigating according to soil moisture readings, it’s possible to apply water when it’s needed and where it’s needed, in the area where roots are established or desired.

It is easy to install soil moisture sensors at the depths appropriate for the particular root systems by boring access holes into the soil and inserting sensors. Some sensors are read at a gauge attached to the probe while others can be connected to a reader or data recording device that displays the moisture value. Sensors can also be adapted to automatically controlled systems by adding switching devices that will allow watering only when the soil moisture is sufficiently depleted.

Fewer Inputs, Better Performance

Managing root zone moisture not only helps use water efficiently, it helps make the best use of other agricultural inputs. When decisions are made based on information gathered through monitoring, nutrients remain in the root zone until absorbed by the plants instead of being pushed out through excessive irrigation. When over-irrigation occurs, nutrients can leach from the root zone and migrate to the groundwater.

Monitoring with soil moisture sensors also allows growers to get the best performance from low-application rate irrigation systems such as drip, microsprinklers, and Low Energy Precision Application center pivot technology. Low-volume irrigation continuously supplies water to replace soil moisture with frequent, slow applications through emitters, drippers, micro-sprinklers, or sprays. When the application rate of the irrigation system is very low, it can be difficult to compensate for scheduling errors. High-application rate systems like high-pressure sprinklers or flood irrigation, can quickly apply large quantities of water to correct diminished soil moisture in the root zone. Soil moisture monitoring ensures a deficit situation is avoided.

Root Zone Management

Microirrigation can lead to poor soil water distribution because it generally wets a small surface area. Distribution of the water into the crop root zone depends on the soil and its ability to transmit water laterally, which can be problematic in lighter soils. The number and placement of emission devices must match the ability of the soil to move water throughout the root system. Roots will not grow into dry soil, so it’s important to monitor soil moisture in the root zone as well as the desired root zone. In climates where seasonal rainfall causes extensive root development of tree crops, like citrus in Florida or California, it is important to ensure adequate irrigation of the outer root system during dry periods. Soil moisture monitoring can take the guess work out of this process.

Monitoring can also help protect crops from salinity. In areas where salinity is a factor, the outward and downward wetting front pushes salts away from the effective root zone. If this process is not continued, salts can move back into the root zone and damage crops.

Sensor Placement

Soil moisture measurement makes it easier to manage many irrigation issues. To be effective, sensors must be placed in active root zones in locations that will accurately represent how the field or area is wetted by the system. It helps to keep in mind that with a drip or trickle system, the emitter wets a very small surface area, with the subsurface moisture forming a “wetted onion” as the soil moves the water downward and outward. With microsprinklers or sprays, a much larger surface area is wetted. In tree crops, sensors should be located at or near the drip line where the active roots are found. In row and vine crops, sensors should be placed in the rows between plants.

Thoughtful interpretation of soil moisture readings from representative locations of the field will tell both when and how long to run the irrigation system, so that the maximum benefits can be achieved, yielding the greatest profit from the crop.

Leave a Reply

Featured Stories
CitrusWith Big Data Comes Big Concerns For Agriculture [Opinion]
January 30, 2015
Many believe technologies like UAVs and precision ag represent the second Green Revolution, but it only will happen if farmers feel safe using them. Read More
Apples & PearsNew Bactericide Now Registered in Top Apple Growing States
January 30, 2015
KASUMIN is active on a wide array of plant pathogenic bacteria, including resistant strains. Read More
FruitsCalifornia Drought Meeting Called
January 30, 2015
State and federal officials will discuss potential actions for the coming year. Read More
GrapesRecord Crowds Flock To California Winegrape Show
January 30, 2015
Unified Wine & Grape Symposium attracts 14,000 industry professionals. Read More
Insect & Disease UpdateResearchers Develop Electronic Citrus Greening Detector
January 30, 2015
New, easy-to-use technology could help growers get a leg up on the disease. Read More
VegetablesSakata Seed Highlights Specialty Golden Beet
January 29, 2015
The company highlights specialty golden beet, Touchstone Gold. Read More
FruitsUse The Off-Season To Focus On Farm Safety
January 29, 2015
Prevention, planning, and preparedness are essential for all agritainment operations. Read More
Protected AgricultureHow To Successfully Produce Vegetables In Controlled Environments
January 28, 2015
Greenhouse expert Merle Jensen offers pointers on growing systems, pest control, plant nutrition, harvesting, and more. Read More
IPMWhat You Need To Know To Maintain An Effective IPM Program In The Greenhouse
January 28, 2015
Greenhouse expert Karin Tifft discusses the importance of scouting, pest identification, control options, and the importance of sanitation. Read More
Apples & PearsPears Get A Hefty Shout-Out From Rapper
January 28, 2015
The pome fruit is on mainstream media's radar thanks to a rapper's quote and ensuing social media blitz. Read More
The Latest
CitrusWith Big Data Comes Big Concerns For Agriculture [Opini…
January 30, 2015
Many believe technologies like UAVs and precision ag represent the second Green Revolution, but it only will happen if farmers feel safe using them. Read More
Apples & PearsNew Bactericide Now Registered in Top Apple Growing Sta…
January 30, 2015
KASUMIN is active on a wide array of plant pathogenic bacteria, including resistant strains. Read More
FruitsCalifornia Drought Meeting Called
January 30, 2015
State and federal officials will discuss potential actions for the coming year. Read More
GrapesRecord Crowds Flock To California Winegrape Show
January 30, 2015
Unified Wine & Grape Symposium attracts 14,000 industry professionals. Read More
Insect & Disease UpdateResearchers Develop Electronic Citrus Greening Detector
January 30, 2015
New, easy-to-use technology could help growers get a leg up on the disease. Read More
VegetablesSakata Seed Highlights Specialty Golden Beet
January 29, 2015
The company highlights specialty golden beet, Touchstone Gold. Read More
FruitsUse The Off-Season To Focus On Farm Safety
January 29, 2015
Prevention, planning, and preparedness are essential for all agritainment operations. Read More
Protected AgricultureHow To Successfully Produce Vegetables In Controlled En…
January 28, 2015
Greenhouse expert Merle Jensen offers pointers on growing systems, pest control, plant nutrition, harvesting, and more. Read More
IPMWhat You Need To Know To Maintain An Effective IPM Prog…
January 28, 2015
Greenhouse expert Karin Tifft discusses the importance of scouting, pest identification, control options, and the importance of sanitation. Read More
Apples & PearsPears Get A Hefty Shout-Out From Rapper
January 28, 2015
The pome fruit is on mainstream media's radar thanks to a rapper's quote and ensuing social media blitz. Read More
FruitsHighlights From The Mid-Atlantic Fruit And Vegetable Co…
January 28, 2015
Bio-control use, media literacy, and disease control were just a few of the topics discussed at the convention held in Hershey, PA. Read More
GrapesCalifornia Table Grape Growers Offer Agricultural Schol…
January 28, 2015
The application deadline for the agricultural scholarships is 5 p.m., Feb. 13. Read More
GrapesNew Wine Hybrid Establishment Cost Resource Available
January 28, 2015
Research from Cornell University breaks down the cost of producing hybrid winegrapes. Read More
FertilizerEasy Access To Fertilization Guidelines
January 28, 2015
New, easy-to-follow brochures take the guesswork out of almond and walnut fertilization. Read More
BerriesDormant Pruning Tips For Your Berries
January 28, 2015
Proper dormant pruning increases berry size and improves overall health of blackberry and raspberry plants. Read More
NutsHow Freezing Temperature Affect Bearing and New Trees
January 28, 2015
Key points before and after the critical bloom period make exposure to freezing temperatures relevant. Read More
CitrusFlorida Citrus Is Still A Big Deal [Opinion]
January 28, 2015
Even while in the grips of greening, citrus continues to be a big contributor to the Sunshine State's economy. Read More
FruitsUSDA Forecast Predicts Normal Water Supply For Parts Of…
January 27, 2015
The Southwest, Sierra Nevada region, and Pacific Northwest are starting the year drier than normal. Read More