Specialists
Speaking
Spray early, spray less DR. JARROD HARDKE ARKANSAS Professor/Rice Extension Agronomist University of Arkansas Cooperative Extension Service jhardke@uada.edu We say it every year, repeatedly, to the point of getting eye rolls: focus on pre-emergence (PRE) herbicides! There’s no single easier way to improve weed control and save money than to get PRE herbicides overlapped and applied and activated early. The earlier we plant, the longer residuals can stretch. But we still want to shoot for the overlap. Planting late March to early April, we can probably get 3-plus weeks out of our first residual (if conditions turn dry, this window shortens). The later we plant beyond that, the window in which residuals will last shortens as temperatures rise and conditions get drier. Suddenly, 2-plus weeks becomes the normal expectation. In row rice, research has shown that getting PREs overlapped at two weeks is critical for barnyardgrass control. Waiting until three weeks to overlap results in major issues. Luckily, flushing for activation in row rice is pretty easy compared to levee rice.
“The earlier we plant, the longer residuals can stretch. But we still want to shoot for the overlap,” says Arkansas rice specialist Dr. Jarrod Hardke.
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RICE FARMING
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MARCH 2022
A stale seedbed approach to planting has been an emphasis for me this year. Getting the ground slicked off, followed by a nice, packing rain works wonders for efficiency. We’ve got all these nice no-till drills. Let’s use them. In a stale seedbed situation, not only does planting efficiency improve (better stands), but weed control also improves. When we plant into a stale situation and can include some burndown and our first PRE immediately following planting, we are way ahead of the game. Now we’re working from a point where the opportunities for weed flushes are greatly reduced. So additional PRE applications will be more effective combatting reduced weed pressure. If we do end up needing a post-emergence application, we’ll be fighting lower densities. Take the fight to weeds early to have the best 2022 season. It’s the best way to keep more money in your pocket.
Dry winter may impact early season weed control DR. WHITNEY BRIM-DEFOREST CALIFORNIA Cooperative Extension Rice Advisor University of California, Davis wbrimdeforest@ucanr.edu Here in California, we’ve had one of the driest January-February periods ever recorded. While still possible, we are not likely to get a large amount of rain in March and April (based on historical weather patterns). What does this mean for early season weed control? If you drill-seed your rice, some weed emergence may be impacted. The soil is going to be extremely dry, meaning that flushes of water may not increase soil moisture enough for weed seeds near the soil surface to imbibe enough water for germination. This will disproportionately impact small-seeded weeds, which cannot emerge from deep in the soil. Some of our smaller-seeded weeds are smallflower umbrellasedge, sprangletop and redstem. Emergence of large-seeded weeds, such as our watergrass species, are likely not to be impacted, as they can emerge from deeper in the soil profile — where the soil moisture content is likely higher — with enough water to imbibe for emergence. For continuously flooded fields, the dry winter will likely cause a slow flood-up. Last year, we saw it take more than a week in some cases, depending on the size of the field. The dryness of the soil, coupled with a lower water table in some areas, may have contributed to the slower-than-normal flooding, and this year will likely look similar. Here are some things to be aware of (again, based on observations from last year). Slow flood-up may contribute to low rice germination rates. This can happen if the soil was saturated for a long time before the rice seed was planted. Rice — like all plants — needs oxygen. If the soil remains satuRICEFARMING.COM
