Measure what matters most: Soil Tension

Joe Wiegand Irrigation SeminarNew technology companies are popping up in agriculture what seems like almost every day, many of which tout the layers upon layers of data that they can deliver to a grower. But with the seemingly endless stream of information flooding into agriculture, it can be tough for growers to find time to determine what is useful and what isn’t, and more importantly, how it can help the bottom line in their businesses.

Hortau hosted an irrigation management seminar in front of a room of Central Valley growers in Coalinga, Calif. on Nov. 29 that highlighted the advantages of real-time soil tension data and how it, combined with Hortau’s grower support service, is helping growers increase crop health, yields and the bottom line.

The seminar kicked off with Hortau Regional Sales Manager Joe Wiegand, who touched on important aspects of agriculture such as pest control and nutrient management, before shifting to the importance of irrigation on crop health and yield. He noted the ever increasing responsibilities of the farm manager, as well as how labor concerns and turnover continue to create headaches for growers nationwide and that it’s often a challenge to achieve continuity in irrigation scheduling when irrigation staff members move on.

But even with that turnover, Hortau, in its 15-plus years of experience, has listened to growers and developed its hardware and service offering to provide them with the support they need to ease staffing transitions and get new employees up to speed with understanding soil tension, the technology and software, helping to prevent gaps in irrigation scheduling that would put the crop at risk.

“It’s a lot faster implementing technology on the farm when you have an irrigation expert working with you in the field,” Wiegand said.

Wiegand pointed to situations where Hortau irrigation management systems have helped growers not only optimize irrigation run times, but determine how the water is moving both vertically and laterally through the soil, making it easier to identify problematic soil wetting issues such as preferential flows.

“Irrigation is not as easy as ‘just go and turn on the water’ sometimes,” he said.

Ben Smith Grower Support Manager

Hortau Grower Support Manager Ben Smith followed Wiegand with a run through of the benefits of real-time soil tension data as compared to other methods of determining soil moisture or plant stress and determining irrigation scheduling.

Among the methods he discussed were hand and feel, neutron probe and pressure bomb, which typically produce data, at best, on a weekly basis. The other two included ET, which relies on approximations to produce a calculated estimation, and volumetric measurements that measure available water depletion and is dependent on soil type. Smith noted that among the first three, neither was available to offer up the information in real time.

“Real-time ET just does not give you the info. that’s exact enough to really work and to really help you keep right on top of irrigation, partially because it occurs after the fact,” Smith said. “ET is always measuring what happened yesterday.”

To drive home the importance of using real-time data, Smith showed what irrigation scheduling based on soil tension over the course of a season looked like based on just weekly data points. In the graph (upper) the weekly plotted points showed that the crop was minimally stressed, or stressed accordingly during major seasonal events such as hull split and harvest.

RT vs Weekly Data PointsThe next slide (lower), however, showed every data point, in real time, for the entire season. In between each of those weekly data points, were a multitude of upward movement of soil tension (stress) on the graph that the grower used to determine when to irrigate. The graphic demonstrated the importance of having objective, real-time data to drive real-time decision making rather than taking a weekly reading to determine when to turn on the water.

“If you’re looking at this once a week, there are many, many irrigations that were missed and a lot of decisions that could have been made,” Smith said. “There’s a lot of potential stress periods for crops that ultimately lead to reduced production.”

Soil tension doesn’t measure water content or volume, but rather the amount of water that is available to the plant, which is more effective than monitoring the water content of the soil because plants regulate their growth via photosynthesis based on available water. Too much water in the root zone (low soil tension) can create anaerobic conditions, where as too little water (high soil tension) can force the plant to work much harder to maintain turgidity. In both scenarios, the plants stress and the stomata close, bringing photosynthesis — and growth — to a halt.

Why is this important? When crops are at ideal soil tension levels they maintain a steady rate of photosynthesis, which translates into more growth, better crop health and better yields. In essence, creating the favorable conditions necessary to coax out the upper limit of the crop’s genetic potential.

Stress Events and Effect on YieldAs stress events accumulate over the course of the season, the potential for yield loss can increase sometimes by as much as 50 percent. By managing stress events, growers give their crops a better chance of delivering higher yields, which translates into a better bottom line.

Growers making even small improvements to their irrigation practices using Hortau precision irrigation management systems saw increase return on investment typically within one season. ROI in traditional almonds was 50 times what was paid for the Hortau irrigation management system, organic almonds 100 times, while table grapes saw an ROI of 130 times.

“The potential is there to not only make your money back, but to really do well,” Smith said. “…The potential is there to really make changes in the way you manage your irrigation and to reap the benefits. It really is an investment. It’s something to look forward to, to increase your productivity.”

Smith closed out the presentation with recognition of all the responsibilities farm managers face throughout the course of a season. With so many tasks on their plate, such as labor, scheduling, equipment purchasing and regulations, it’s not hard to see why irrigation can sometimes get put on the back burner.

With Hortau’s precision irrigation management system and support, growers are better able to make understand the measurement that matters the most and make informed decisions on irrigation management.

Want to learn more about Hortau’s irrigation management system? Meet with Hortau at an upcoming show or contact us to get notified of our next irrigation management seminar.