Like many county public works departments, the one in San Joaquin County, California, has its hands full with invasive weed management. Not only on county roadsides but also with several hundred miles of county-managed levees. Both are breeding grounds for all types of tough invasive weeds, and without effective management, these invasive plants turn into dangerous fire hazards, inhibit roadside visibility and impede the flow of water.
For much of San Joaquin County — situated just east of San Francisco — that responsibility rests squarely on the shoulders of Eric Ambriz and his maintenance team. Based in the county seat of Stockton, Ambriz is the superintendent, channel maintenance division with San Joaquin County. He manages vegetation in zones 9 and 10, which encompass 350 miles of Priority 1 roadways, 350 miles of nonproject levees and 117 project levee miles.
“For roadsides, we start where Caltrans stops,” Ambriz says. “Most of what we do is preemergence spraying Zone 1 to bareground, but there’s also many medians we have to keep bareground.”
The same is true for the levee miles the county manages — the access roads and levee banks must be treated to bareground to both keep water flowing and to prevent the further spread of invasive weeds, which can drop seeds in the water that then spread to new locations downstream.
Keeping mixes simple and effective
To simplify these similar applications, San Joaquin County wanted a singular herbicide mix flexible and effective enough to work in both use sites. The goal was to achieve both a quick burndown and get long-lasting residual control on prevalent species, such as yellow starthistle, ryegrass, Johnsongrass, Russian thistle and marestail.
A few years ago, it moved to a total vegetation control mix featuring Cleantraxx® herbicide with indaziflam. Ambriz explains why.
“Cleantraxx just stays put, and that helps it to work really well,” Ambriz says. “It is excellent on ryegrass — it has a great burndown on it. Plus, it’s proven to hold for upward of two years in the right conditions on many sites we’ve used it on.”
In addition to burndown and residual control, Ambriz appreciates other characteristics of the mix.
“Many crops grown in the area are tolerant to Cleantraxx, so that allows us to use it around sensitive sites like agricultural areas,” Ambriz says. “Also, we’ve been proactive in moving away from using glyphosate where we can, in favor of alternatives like Cleantraxx, and it helps mitigate concerns from the general public.”
The benefits of custom blending
Starting almost four years ago, working with Corteva Agriscience and Nutrien VM Solutions, San Joaquin County began taking delivery of its new bareground mix via a returnable, refillable container management system. Herbicides comes preblended to exact specifications. The major benefits to Ambriz are threefold: quicker spray prep, less handling and cleanup, and better inventory management.
“We can’t sit and wait for an ideal spray day,” Ambriz says. “There’re too many factors that can impact it — like dealing with scheduling conflicts with mowing crews or sudden changes in the weather. High winds can stop us in our tracks.”
Most days, San Joaquin County spray crews work to make applications during a two- to three-hour window in the morning, before the area’s notorious winds begin to pick up. That means being as efficient as possible in getting prepped and on the road as quickly as possible.
“With this system, our crews spend much less time getting ready to spray in the morning,” Ambriz says. “Timewise as far as not having to mix, it saves us anywhere from 30 minutes to one hour every morning. This is critical when you only have a couple hours a day to spray. Also, it greatly reduces the cleaning, rinsing and handling involved.”
Ambriz notes that it’s now much easier to keep tabs on product inventory, without having to account for piles of quart jugs. Additionally, the blended mixes have proven very compatible with the county’s injection spray trucks.
“The blends stay in suspension really well,” Ambriz says. “You can shut our truck off, just clean out the pump — then come back a couple days later, agitate and pick up where you left off spraying. It’s a big improvement over previous mixes, where guys would have to clean out the whole truck every time they stopped.”
With more effective control and increased operational efficiencies, San Joaquin County will continue to win its war on weeds.
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