The San Joaquin Valley of California is one of the top fertile regions in the world that settles above a large groundwater aquifer that is prime for high quality agriculture production. But at what cost?
As the San Joaquin Valley receives minimal rainfall in a hot Mediterranean to desert climate, irrigation is often required to supplement the remaining crop water demand. Crop irrigation seems a simple concept from afar but is complex when a grower needs to decide when and how much to irrigate. Old school irrigation scheduling like the calendar method or observing visual water stress symptoms of the crop (e.g., curled corn leaves) seemed to work but has limitations that can prevent the ability to achieve profitable irrigation efficiencies.
To address those limitations, on-farm irrigation water management (IWM) tools were developed. One of the earliest instruments was the classic Irrometer tensiometer beginning in 1951 to measure how dry the soil can get. As ground and surface water regulations became stricter in the last half of the 20th century, universities and manufacturers made efforts to rapidly advance irrigation technologies to meet the modern farm’s increased irrigated acreage with set water allocations.
Key variables such as soil type, level of salt content in the soil, weather (e.g., wind, temperature, & humidity) are just a few that can influence irrigation scheduling. The latest IWM tools like soil moisture sensors (fig. 1 & 2), flowmeters (fig. 3), weather stations, and automation valves eliminate a lot of guesswork by scientifically measuring the appropriate variables.
The producer now can make a confident decision before each potential irrigation event using real-time field data remotely accessed on any mobile device or computer. An analogy often used by many irrigation professionals is the fuel gauge analogy. How does a driver know how much fuel is left in the tank without a fuel gauge indicator. The same can be attributed with how much water is being pumped into a field and infiltrated into the soil versus leaving the field as runoff.
Unlike other major agricultural regions in the United States that have a shorter irrigation season for various crops compared to the Central Valley, soil moisture sensors can be useful for most of the year such as in orchards where some producers do irrigate beyond the fruit and nut harvest.
Irrometer factory representative, Jacob Moreno, explains the potential for reduced groundwater pumping by trusting the soil moisture sensor and to know when to terminate irrigation for the season. “When the tree enters dormancy, the soil moisture data can show when the tree stops using water.” Producers can apply for government subsidies to offset the initial cost for soil moisture monitoring technology or any other IWM tools. “The grower will get a better return by using the water at the right time and at the right place,” according to Moreno.
Moreno further explains the two hardest challenges the Irrometer faces in the adoption of their technologies as the producer has several soil moisture sensor types to choose from. “The first factor is the price and producers not being aware of how affordable the sensors can be. The second factor comes down to how easy or how hard it is to use the sensors.”
Wiseconn Engineering representative, Darryl Hadlich, describes one of the biggest challenges of incorporating the latest on-farm technologies. “Retro-fitting old manual irrigation systems with butterfly valves that requires more than just slapping on an automation box is one of the hardest challenges I see.”
On the other hand, these challenges can be minimized by incorporating automation such as the popular Wiseconn X1 node that connects into new irrigation systems. “Investing in an irrigation system design that includes infrastructure for automation is very important,” said Hadlich.
Adriano Lourenco, a Pacific SouthWest Irrigation (PSWI) salesman for the Ballico territory, explains that the benefits outweigh the costs for investing in these tools. “With increasing labor costs, automation makes it easier to manage and control on-farm irrigation systems.”
As an irrigation dealership, PSWI is responsible for complete automation installation and troubleshooting all year around. The Sentek Drill and Drop soil moisture sensor installation is one of them as shown in figure 4.
Coming next month, “Center Pivots Face Small Existence in Central Valley”
To learn more about what Pacific SouthWest Irrigation does, please visit the website (https://pacsouthwestirr.com/) and the instagram account (@pacswirrigation)
Jacob is a quality control & design engineer at Pacific SouthWest Irrigation in Stockton, CA. As a native of Omaha, Nebraska, Jacob went on to earn degrees at the University of Nebraska-Lincoln and at Mississippi State University. He is passionate about groundwater sustainability and strives for educational outreach through agricultural photography and writing.