Arkansas Rice Update 7-28-23

by Jarrod Hardke, Rice Extension Agronomist - July 28, 2023

Arkansas Rice Update 2023-19

July 28, 2023

Jarrod Hardke, Nick Bateman, & Ben Thrash

“I’m gonna turn up the heat, I’m gonna fire up the coal.”

Hot Tamale

To begin the week, temps looked warmer but like we would get at least nighttime relief.  Not so fast, my friend.  Daytime highs and overnight lows have now crept back up.  The good news is the forecast continues to change and present a more varied outcome over the next 10 days.

The majority of rice in the state is at various stages of heading.  The daytime highs appear to want to try and stay in the upper 90s, but that isn’t overly concerning at this stage.  Not great, but not the worst.

However, the nighttime lows are trying to hover around 75 degrees for an extended period.  This is definitely concerning.  From a quality standpoint, our rice tends to get chalky when we have greater than 4-5 consecutive nights or more at 75+.  The longer the period the worse it gets.  The higher those temps are the worse it gets.

In past years when these conditions occurred and led to yield loss, there wasn’t much change between the high and low each day, we were ranging from 78 at night to 92 in the day (for example).  This led to massive humidity and dew sets almost like it rained every night.  The massive amount of physical moisture every day and prolonged into the flowering period each day can really mess up pollination.  Water vapor (humidity) is good for pollination, physical water from rain and dew is bad.

At the moment, we’re getting hot enough during the day to burn off the physical moisture that can impede pollination.  It’s still miserable for us to be out in but won’t necessarily blank kernels.  The quality is of greatest potential concern at the moment.  But that stress from high nighttime temps can still negatively affect pollination, so there is a degree of wait-and-see to these events.

Keep fields well-watered so that moisture deficient stress (hot spots) doesn’t rob us during pollination and grain fill.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Table 1.  9-day temperature outlook for Stuttgart and Jonesboro (as of 7/28/23).

New on Arkansas Row Crops Radio this week:

Weeds AR Wild Series, S3 Ep16:  Late Weed Seed Control and Options for Ratoon Rice

Rice Leadership Development Program Now Accepting Applications

The Rice Leadership Development Program gives future leaders a comprehensive understanding of the rice industry, with an emphasis on personal development and communication skills.

Applications will be accepted until September 8.

Class members attend four one-week sessions over a two-year period that encompass studies of all aspects of the rice industry through firsthand observation.  They also attend seminars and workshops designed to strengthen leadership skills.

To be eligible for the Rice Leadership Development Program applicants must derive their primary livelihood as rice producers or from a rice industry-related profession or firm, including rice mills, rice product marketers, sales officials, suppliers, dryers, extension services, research facilities, etc.  Participants from the industry-related category must serve the rice industry in their primary job responsibility.  Applicants must be between the ages of 25 to 45 at the time of application.  Go here to apply for the program.  For additional information, please contact Program Director Steve Linscombe.

Insect Update

Nick Bateman and Ben Thrash

Rice stink bug pressure has been low over the past week.  Most fields are reporting numbers below threshold at this point.  However, based on the number of nymphs observed in fields and on heading grasses in and around fields, we need to watch out for an increase in numbers over the next 7-10 days.  Keep scouting on fields still susceptible to damage.

As a reminder for the early fields approaching draining – we recommend terminating insecticide applications at 60% hard dough (straw-colored kernels).  If your stink bug numbers are below threshold at this point you should be safe to let it go.  However, if they are above threshold at this time, it may be advisable to make a clean-up application.

There have also been reports of some fields with fall armyworm present.  In maturing rice fields, it is rarely advisable to spray for fall armyworm.  In general, unless larvae are clipping flag leaves or clipping heads, there isn’t an advantage to spraying solely for armyworms.  Based on observations over the years it would probably take greater than 30% of heads with larvae on them to justify an insecticide application.  Yes, it’s alarming to find any armyworms feeding directly on kernels, but this rarely occurs.

Drain Timing Considerations

Jarrod Hardke

It’s that time of year to dust off the comments about drain timing.  The hot and dry conditions observed last year around and following drain timing make these comments even more relevant.  Some yield issues as well as standability issues could be explained last year by drain timing.  It’s worth noting that some fields weren’t drained noticeably early, but we need to drain like it’s never going to rain again.  Last year it didn’t rain again, and we saw some of those impacts on fields that may have benefitted from holding the water just a little longer.

Some of the earliest planted rice fields in the state have already been drained with the first fields hopefully to be harvested sometime in the next week to 10 days.

The upcoming forecast is hot, but variable and uncertain.  When the outlook is for mild and wet conditions we can dry a little early with no penalty; but when weather is warmer with no rainfall, early draining can lead to early plant death and reductions in yield and milling.

As a general rule, we recommend draining fields 25 days after 50% heading for long-grains and 30 days after heading for medium-grains.  The DD50 Rice Management Program builds this number of days into its drain timing recommendation.  However, as temperature, rainfall, and humidity can impact how quickly kernels actually mature, it’s important to do more than just count days and drain.

It’s preferred to look at the number of recommended days as a guide, but then to look at the relative maturity of the crop from a visual standpoint.  Fig. 2 shows a general guide for determining relative grain maturity for drain decisions:

• Left, nearly all kernels are straw-colored – safe to drain regardless of soil type.

• Center, 2/3 of kernels are straw-colored – safe to drain on a silt loam soil.

• Right, 1/3 of kernels are straw-colored – safe to drain on a clay soil.

Assume it’s never going to rain again when you’re draining your fields.  If the rice couldn’t make it safely to maturity under those conditions, hit the pause button and wait.  Stay on the side of caution to protect yield and quality.  Use a combination of the days after 50% heading guideline (25-30 days) and the relative grain maturity in the field to make your drain decisions.

Fig. 2.  Rice panicles at different maturity levels described by kernel percent straw color:  (L) 100%, (C) 67%, and (R) 33%.

Field Day Reminders:

Aug. 3 – Rice Field Day, Rice Research & Extension Center, Stuttgart, AR

Aug. 10 – Pine Tree Field Day, Pine Tree Research Station, Colt, AR

Aug. 16 – Rice College, Rice Research & Extension Center, Stuttgart, AR

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2023 season.  All log-in and producer information has been retained from the 2022 season, so if you used the program last year you can log in just as you did last year.  Log in and enroll fields here:  https://dd50.uada.edu.

Use the Arkansas Rice Advisor Internet App!

The Arkansas Rice Advisor site https://riceadvisor.uada.edu functions like an app on your mobile device.  There you can readily access the DD50 program, rice seeding rate calculator, drill calibration, fertilizer and N rate calculators, publications, and more.

Additional Information

Arkansas Rice Updates are published periodically to provide timely information and recommendations for rice production in Arkansas.  If you would like to be added to this email list, please send your request to rice@uada.edu.

This information will also be posted to the Arkansas Row Crops blog (http://www.arkansas-crops.com/) where additional information from Extension specialists can be found.

More information on rice production, including access to all publications and reports, can be found at http://www.uaex.uada.edu/rice.

Acknowledgements

We sincerely appreciate the support for this publication provided by the rice farmers of Arkansas and administered by the Arkansas Rice Research and Promotion Board.

The authors greatly appreciate the feedback and contributions of all growers, county agents, consultants, and rice industry stakeholders.