Arkansas Rice Update 8-25-23

by Jarrod Hardke, Rice Extension Agronomist - August 25, 2023

Arkansas Rice Update 2023-23

August 25, 2023

Jarrod Hardke and Tommy Butts

“I just can’t waste my time, I must keep dry.”

Out of the Frying Pan and Into the Rice Cooker

Someone turned things up to 11 on the heat.  It’s been roasting, to put it mildly.  This is putting many in a better position to get started with harvest, but it’s been far from pleasant.

For fields that were ready to be drained but hadn’t been yet, it created an interesting situation.  On one hand, an opportunity to get fields drained and dried quickly, but on the other hand, a risk of drying fields out very rapidly that still need to finish up.

We learned a lesson last year that even when draining “on time” it can still be too early if conditions are extreme.  Last season we saw premature plant death and collapse that caused some harvest issues.  Not true lodging, just plants dying out and unable to hold up to the weight of grain.  Hopefully we’ll escape similar issues this fall.

Confirmed yield reports are still somewhat limited, but so far, the general consensus still seems to be a positive one with most fields cutting in line with or greater than expected.  By next week a much larger number of machines should be rolling and we’ll begin to get a better picture of how things are shaping up.  By then we should have some early milling yield reports as well to have an idea of how quality is starting out.

Grain moisture is up to some funny business once again in the early harvest stages.  Those with moisture getting lower are seeing it bottom out with the heat this week.  Others with rice just getting to an acceptable moisture have reported seeing it want to hang up there at borderline levels.  The rapid drydown makes sense given the heat, but what gives with some of it hanging up?  One guess is that it’s spiking mid-afternoon when humidity is bottoming out and more moisture is “cooking” off the rice plants.  Well, it’s a theory anyway.

Looking ahead, we get a cooldown next week with slight rain chances that will be a major change of pace compared to current conditions.  The long-term outlook after that is for things to warm back up some and continue to be mostly dry and warm into the early part of September.  The latter part of September could see a return of rainfall though, so making the most of early harvest progress could pay off.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Fig. 2.  Arkansas rice harvest progress, 2012-2023.

Preliminary Yield Data

Jarrod Hardke

Table 1 contains preliminary yield data from a single Arkansas Rice Performance Trial location harvested to date.  Reminder:  this data is preliminary because we haven’t fully analyzed it yet – so it may look different in its final form presented later this year.  Since we start getting questions about performance data already, we’re showing this now and will continue showing others as they're harvested for an ‘early look’.

Table 1.  Preliminary Arkansas Rice Performance Trial data (Arkansas Co., Gillette, AR, planted 3/30/23).

*Grain Type:  L = long-grain; M = medium-grain; CL = Clearfield long-grain; CM = Clearfield medium-grain; FL = FullPage long-grain; ML = MaxAce long-grain; PL = Provisia long-grain.

More on Harvest Aids

Jarrod Hardke

Salt (sodium chlorate) is a tool – but it doesn’t always do as much as you think.  In 2018 when we were revisiting some of our harvest aid timings, we noted that from around 25% grain moisture, we dropped an average of about 1% moisture every two days (1/2% per day) without applying salt.

Three days after applying salt (when we recommend beginning harvest) moisture was usually 1.5-2.0% lower than had we not salted.  This means that in some cases, depending on conditions, we may not be at moisture level where we want to begin harvest if we salt at high moisture.  The last thing we want to do after a salt application is wait until 6+ days after application to begin harvest.  After day 5, results can start to become erratic from both a yield and milling standpoint.

We want to be fairly close to the moisture we're willing to begin harvest before applying sodium chlorate.  Applications made too early that force us to let the rice sit longer in the field to reach our target moisture opens the door for problems as plant material becomes too dry to hold onto the grain.  And you have to hope the wrong rain doesn't catch you between salting and harvest or there could be excessive shattering and lowering of milling yields.

Side note:  In 2019 when we looked at multiple cultivars starting at 20-22% moisture, it turned very hot and moisture fell 1% per day (again without applying salt).  So, in 7 days we observed a fall from 20-22% moisture to 13-15% moisture (the average high those 7 days was 95).

I’ve heard some comments about rice getting to 26-27% moisture and folks wanting to salt the rice to get started.  Do not seek the treasure.  This is a bad idea.  Rice at that high moisture still has milky kernels that you will terminate with the salt application – terminate means stop them in their tracks and eliminate them from contributing to yield.

For varieties, wait until grain moisture from a combine sample is below 25%; for hybrids wait until grain moisture is below 23%.

Not interested in taking a combine sample but instead want to pull a hand sample?  That’s one way to go, but whatever moisture you get from a hand sample, add AT LEAST 2% to your number.  We pull a lot of hand samples preparing for harvest of plots and we frequently find that the difference between a hand sample and a combine sample to be 2-3% (the hand sample is always lower).

Soybean desiccant drift on late season rice

Tommy Butts

Some phone calls have started coming in asking about the impacts that soybean desiccant [Gramoxone (paraquat), Sharpen (saflufenacil), and salt (sodium chlorate)] drift will have on late season rice.  In addition, further questions have arisen about the impacts of potential drift of late season soybean herbicide applications to control grass escapes (glyphosate and clethodim) will have on rice at this stage.

First and foremost, our goal should be to NOT drift onto neighboring crops regardless of the potential or lack thereof for injury.  Herbicides, particularly systemic ones, can do some very crazy things from time to time when plants are in reproductive stages.  Minimizing the likelihood for drift (proper sprayer setup, waiting for the right wind direction, etc.) will help to mitigate potential problems such as yield loss or reductions in quality that can cause dockages or outright buying point refusals.

In the event that drift does occur onto our rice at this stage from a late season soybean application to control grasses or desiccate the crop, there’s a couple of things to watch out for.  First, minimal to no visual injury symptoms are typically observed from drift rates of herbicides when rice is in the reproductive stages.  The results of the drift incident will only be evident once the combine rolls through the field.

When it comes to yield loss, recent research out of Mississippi has shown that simulated drift rates of Gramoxone (paraquat) can cause some fairly significant yield losses and reductions in grain fill due to drift occurring anywhere from 50% heading (16-19% loss) up until one week prior to harvest (5% loss) (McCoy et al., 2021b).  Additionally, seed weight (grain fill) was reduced for all application timings of simulated paraquat drift except for one week prior to harvest.  Simulated drift rates of glyphosate caused reductions in yield (6-19% loss depending on timing), but no losses in grain fill occurred at any point from 50% heading to one week prior to harvest.  In contrast, simulated drift rates of Sharpen (saflufenacil) and salt had no effect on rice yield or grain fill.  Additional research suggested that inbred cultivars tended to be more sensitive or result in more yield loss from late season drift events of desiccant herbicides (McCoy et al., 2021a).

As we’re nearing the end of the season, and we see the light at the end of the tunnel, let’s make sure to take care to avoid these drift situations and allow everyone to finish off on a positive note. Good luck out there!

References:

McCoy, J., Golden, B., Bond, J., Dodds, D., Bararpour, T., & Gore, J. (2021a). Rice cultivar response to sublethal concentrations of glyphosate and paraquat late in the season. Weed Technology, 35(2), 251–257. https://doi.org/10.1017/wet.2020.112

McCoy, J., Golden, B., Bond, J., Dodds, D., Bararpour, T., & Gore, J. (2021b). Rice response to sublethal concentrations of paraquat, glyphosate, saflufenacil, and sodium chlorate at multiple late-season application timings as influenced by exposure. Weed Technology, 35(6), 980–990. https://doi.org/10.1017/wet.2021.61 

Fig. 3.  Example of paraquat drift onto early season rice to show symptomology (later season drift may differ in appearance).

Rice Market and Harvest Progress

Jarrod Hardke

This week we’ll shift our attention to November rice futures.  A year ago at this time, futures were ~$1.50 per cwt greater than where we are now.

Fig. 4.  CME Rough Rice Futures, Sept. 2023 and Nov. 2023, Three-month daily chart.

Harvest Progress:

In Monday’s Crop Progress, USDA estimated the U.S. rice harvest at 18% complete for the week ending August 21^st, up from 14% the prior week.  It appears most are slightly ahead of the 5-year average with LA further ahead than most.

The heat in the Midsouth this week with an expected cooldown and minimal rainfall chances should see further improvement in harvest progress over the next 10+ days.

Table 2.  Rice Harvested (%).

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.