ONV avocado irrigation

An irrigation flow test on avocado trees can help the grower dial in the system. Similar techniques can be used on other types of trees, experts say.

Avocado growers spend a lot of money on irrigation, but there is wide variation in performance and efficiency among systems available in the market, something the average grower may not realize.

To help growers assess how their current systems are doing and to help others choose the right system, experts like Stuart Styles offer a helping hand.

Styles is an irrigation specialist and director of the Irrigation Training and Research Center at California Polytechnic State University in San Luis Obispo.

The California Avocado Commission has had him do encores of his talks for several years, to reach more growers with this critical information. Styles worked with the commission to set up parameters and protocol for assessing the performance of micro sprayer drip systems, which are commonly used for tree crops such as avocados, almonds and pistachios, so this information can be applied to other tree crops as well.

“Getting growers to understand these terms is challenging, since they’re busy and juggling a lot of things. They also assume that at an average of $1,500 per acre, the systems should be working quite well, just because they paid so much for it,” Styles said. “Not all of them work well, some are actually pretty bad.”

Growers who participated in his seminars were shocked to discover there already is a lot of published literature put out by ITRC grading various systems, yet they had bought some of the poorly rated ones without realizing it.

“ITRC names the brands and assesses them,” Styles said. “It’s a little controversial, but it’s not always the system’s fault, it’s also how the growers manage the system.”

The problem can be in three areas — the design could have flaws, how it was manufactured might be the issue or the way growers manage it could be wrong.

With design, it could be that the system does not have a high enough minimum pressure programmed into it, which affects the flow of water in the grove.

Even if the sprinkler system has been designed right and manufactured correctly, growers could inadvertently mismanage the system, and end up with low performance. Someone with an 80-acre system that has 6 irrigation zones might decide to reduce the number of zones to finish watering sooner. But if they do this, the pressure can drop and they may not realize it.

When installing sensors in the field, it’s important to know where to place them to get the best read on the ground situation and to decide where to irrigate. When Styles asks growers at workshops where they would place them, everyone guesses.

There’s a choice between the driest parts of the field, the wettest and the moderate or average zones that get adequate water.

“There is no right answer,” he said. “It depends on what information you need from the sensor. Growers who want to assess the dry part of the field should place sensors there to apply adequate water. If you put your sensors in the wettest part of the field then your dry areas won’t get enough, because you’ll apply less water based on the wet parts.”

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