Arkansas Rice Update 6-14-24

by Jarrod Hardke, Rice Extension Agronomist - June 14, 2024

Arkansas Rice Update 2024-11

June 14, 2024

Jarrod Hardke and Bob Scott

“It’s time to ramble on, ramble on.”

Sun and Heat

You wanted the heat, now you got it.

A generally open forecast over this past week continues into the next, and with it, excellent rice growing conditions.  As we creep into the mid-90s it’s often been described that as we start to get fairly uncomfortable with the temperature the rice gets very happy.  We’re hitting a stride of finally maximizing heat units (DD50 units) and an already speeding crop should speed up even further.

Note that some have commented that the DD50 program appeared to be behind in its estimates this year for reaching certain dates.  The program “gets smarter” as the season goes along, updating every night.  Let’s say you enter a field in the DD50 program the day it emerges – the program uses historical weather data to estimate when we’ll hit various stages.  But every night, the program replaces the historical data with what actually happened – so every day the program gets more accurate for this year.  So, if you haven’t run a new report in a while, please run a new one to get the most updated predictions.  Even better, sign up to receive text or email alerts for when you’re approaching key stages.

Check out comments below on agronomic and weeds issues we’re facing of late.  Beyond those, it’s time to keep the water to the crop and avoid drought stress during internode elongation, particularly around ½” internode elongation when we’re forming the panicle and grains.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Ricing Around

Jarrod Hardke

• Don’t guess, tissue test! Odd deficiency symptoms have a tendency to show up as rice enters reproductive growth stages.  Don’t spend money on a guess – collect tissue samples from both good and bad areas for nutrient analysis.  Often when deficiencies take on strange appearances, it will be the difference in the results from good and bad areas that clearly point us to the problem.  Sometimes when sampling the bad areas alone, the results still don’t point in a clear direction.

• Correcting deficiencies – if you find you have a phosphorus (P) or potassium (K) deficiency, the correction is usually pretty simple. Apply 100 lbs of triple super phosphate (TSP) or 100 lbs of potash into a stable flood.  It is taken up pretty quickly by the plant and yes, you have time to wait on tissue sample results to make the correct decision and get the yield benefit out of the fertilizer.  If it’s zinc (Zn) we need to drop the flood, apply 1 lb Zn chelate, then 100 lb ammonium sulfate, and reflood.  Granular Zn will not dissolve fast enough to be of benefit in these recovery situations and it’s tough to apply at a low rate.

• Keep your eyes out for rice water weevil adults post-flood. Nick Bateman noted 25-30 RWW adults per 10 sweeps in some trial work this week just a few days after going to flood.  Depending on time to flood and seed treatment used, we may need to act.

• Once more for clarity on midseason nitrogen timing for varieties – wait at least 4 weeks after preflood N was incorporated before applying midseason N. We want to be in reproductive growth when this application is made (and that’s pretty much always the case 4 weeks out).  Waiting at least this amount of time is where we have seen the greatest benefit from midseason N on varieties.

• Salt issues have been showing up this week with the heat and more north winds ( 2). Some of this will come and go, others will stay.  In flooded fields, once the flood is on, the salt issues will stop in the paddies and the problem will start on the levee tops.  So get the field to flood and the paddies will be ok.  In furrow-irrigated rice it’s more problematic – the bed tops will show the salt issue and furrows won’t.  Same reason as levee fields – when water is moving down the furrows the salt concentrates to the bed tops.  In between irrigations the bed tops will improve as the salt spreads out.  The bottom of the field that is flooded won’t show the issue.  Change water sources if possible, and minimize the amount of time water is standing in the furrows.

• Delayed phytotoxicity syndrome (DPS) continues to make some rice sick ( 3). Fungi in the soil break down common rice herbicides making them toxic to rice under saturated / flooded soil conditions.  Drop the flood to help alleviate the problem.  Leaving the field flooded makes it tough for rice to recover.

Fig. 2.  Salt injury to rice on bed tops in furrow-irrigated rice.

Fig. 3.  Delayed phytotoxicity syndrome from rice herbicides.

Bobbing and Weeding

Bob Scott

Scattered thoughts on weed control.

Jarrod did a good job last week summing up the impending or passed cutoff dates for many of our rice herbicides as we approach or pass certain growth stages like green ring and ½-inch internode elongation.  See last week’s newsletter if you missed this.

It’s also a bad time of year to be a weed guy.  Getting lots of pictures of big weeds and misses, etc. that frankly we no longer have the tools in the toolbox to control.  One example is large crabgrass.  My recommendation at this point is Ricestar HT at 24 oz/acre and pray.  If it’s past green ring you can run Clincher and oil, but this late I have not had the best results from Clincher.  For fields where crabgrass is getting worse or always showing up later in the year, think about adding a shot of Prowl around a mid-post timing – prior to crabgrass germination.

I also wanted to mention that if you are nursing a field of rice back from some of the herbicide injury that we have previously mentioned and thinking about fertilizing and flooding.  Choose your pre-flood herbicide carefully and try not to re-injure the rice.  It will sometimes be more susceptible to burn or other symptoms that those products might cause if not fully recovered.  Clincher plus Prowl is a good option that will probably never hurt rice.  Propanil plus Gambit on most soils and at lower rates is another example.  Most of you know what herbicides are safer on your farm’s soil type and pH.  Most Clearfield/Provisia/FullPage/MaxAce treatments are safe on those tolerant varieties, just follow the label on rates and timings.

I know there are some later fields out there just going to flood.  Don’t forget about two newer options Loyant and Rogue.  I once described Rogue as a “layby” for rice.  That is because it should be used after a permanent flood is established and can be held with little to no water movement.  Rogue works best in zero grade or straight levee leveled fields and will control Sprangletop, annual sedge, many aquatics, and suppress some red rice (see label or MP-44).  Rogue can be a good tool in many circumstances or a waste of money in others so be sure it has a fit on your production system and target weeds.

I like Loyant preflood at a pint/acre or at the lower rate of 0.8 pint/acre in row rice or levees for pigweeds.  It works best as a final preflood treatment following successful overlapping residual program earlier in the season.  It should be applied prior to panicle initiation.  Good control of annual sedge (including ALS resistant sedge), broadleaves, aquatics, and variable control of barnyardgrass (again, see MP-44 for other specifics and precautions).

CBOT September Rice Futures, 10-Year Monthly Continuation.

DD50 Rice Management Program is Live

The DD50 Rice Management Program is live and ready for fields to be enrolled for the 2024 season.  All log-in and producer information has been retained from the 2023 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.