Arkansas Rice Update 5-26-23

by Jarrod Hardke, Rice Extension Agronomist - May 26, 2023

Arkansas Rice Update 2023-10

May 26, 2023

Jarrod Hardke and Trent Roberts

“We’re one day closer to rain.”

Desert Air

Well, we’re now essentially planted up.  Most have been through for a while now, but some late fields were still going in just this week.  I’m sure there are some scattered fields that may still fall in after dirt work is completed, but we reached the main finish line prior to June this year and that’s a big win compared to recent years.

Now our attention turns to the change in weather pattern.  I know we’re all shocked (sarcasm) that the rain stopped and we’re now in an extended dry window.  A few here and there caught scattered rains last week with some of those seeing large amounts.  Most, however, have gone a decent stretch with no appreciable rainfall.

The lack of rainfall, combined with a frequent north wind, are applying stress to rice now.  Rice that’s under stress will display more frequent response to herbicides, even our normally safe ones.  All of the herbicides are generating responses to some degree, but most are minimal and will grow out quickly.  Calls about quinclorac and flash from ALS herbicides have been most common.

Remember that stressed rice going to flood can exaggerate things.  Rice *tolerates* a flood.  If it’s a little stressed then the flood can act as an additional stress.  Rice agronomy 101:  if rice is sick and it has no water, give it some; if rice is sick and it has water, take it away.

Drift and tank contamination issues also continue this week.  Don’t ignore field symptoms that may be abnormal – check in with your county Extension agent or specialists if something doesn’t look right.

It’s not looking very likely, but let’s hope the small rain chances forecast for next weekend turn into something measurable to resolve some of our issues.  At the moment it appears a long, hot summer is upon us – let’s hope not.

Let us know if we can help.

Fig. 1.  NOAA 7-day precipitation forecast.

Table 1. U.S. Rice Planting Progress as of May 14, 2023 (USDA-NASS).

Fig. 2.  2012-2023 Arkansas rice planting progress by week (USDA-NASS).

Recovering From Herbicide Injury

Jarrod Hardke

When herbicide injury of any kind occurs, the most common question is what can I do to help the rice improve?  Unfortunately, the answer is “give it time”.

Over the years, various tactics have been evaluated, from applying DAP or AMS or some other product and flushing the field.  Nothing has shown any consistent beneficial response other than giving the crop time to improve.  Avoiding any additional stresses is most advised, which can mean waiting to apply herbicides which could cause additional injury.

Once rice plants are producing new, healthy green leaves, we can generally be considered well on the road to recovery and may be able to manage as normal.  However, be careful not to burn the new healthy leaves with herbicides and further slow progress.

Weed control is always at the forefront of our mind in rice, but we need a healthy crop to make yield first.  We’ll do the best we can to manage weed situations once the rice is back on track.

Crop Improvement Products

Jarrod Hardke

There is talk each year of foliar products to improve yield.  It’s been a few years but Fig. 3 shows some data where we compared popular foliar products at their recommended rates and timings to untreated plots.  There was no noticeable yield response for any of the products evaluated.  Note that these trials were well managed and there was no noticeable stress on the rice.

Fig. 3.  Rice grain yield response of various crop improvement products.

Quinclorac Products and Rates

Jarrod Hardke

There has been some confusion this season on the use of quinclorac products and appropriate rates for each.  The most common products are Facet, Quinstar, and Prize.  These have different use rates!

The rate range for Facet is 22-43 oz/acre while the rate range for Quinstar and Prize are 8-16 oz/acre.  Use of rates outside these ranges is off label and can result in excessive crop injury.  Use caution when applying these products to ensure the appropriate rate.

Table 2.  Common quinclorac herbicide products and rate ranges.

Flooded Rice Nitrogen Recommendations

Jarrod Hardke and Trent Roberts

The Nitrogen Rate Calculator (https://riceadvisor.uada.edu/nrate/) is available to help get immediate N rate recommendations for most available cultivars.  The calculator is built to account for N rate adjustments based on cultivar, soil texture (soil type), and previous crop.  These are base recommendations and actual N rate used should be adjusted based on experience and additional tools.

General comments on flooded rice N recommendations:

For hybrids, we emphasize a two-way split using a preflood application and a late boot application.  Some continue to try and move the late boot application up into more of a midseason timing – if you’re doing this and think you’re getting a noticeable response, then I don’t think your preflood N rate is high enough.  As with most rice cultivars the preflood N is responsible for most of the yield potential.  Significant yield responses or yield increases >4 weeks post-flood often indicate that the preflood N rates were inadequate or that there was significant N loss leading to low N uptake efficiency.

For varieties, we’re still trying to move toward more of an optimum single preflood (SPF) approach where we eliminate the midseason N application.  This will allow us to maximize yield while saving on N input via a reduction in the season total N rate.  To successfully utilize the SPF approach for varieties, we need to treat urea with NBPT, be able to flood timely (around a week’s time), and keep the field flooded/saturated for as close to 3 weeks following the initial flood event as possible.  Using multiple inlet rice irrigation (MIRI; polypipe) can help tremendously with this, in addition to the water and pumping cost savings that go along with using MIRI.

If an SPF approach does not fit your farm or fields, then using a preflood followed by midseason approach is still good.  Just remember that we’re no longer as concerned about the exact growth stage for the midseason timing – instead, we want to focus on being at least 4 weeks since the preflood N was incorporated AND be past green ring (into reproductive growth).  The window for successful midseason N application is very wide, the worst we can do is apply midseason too early before all the preflood N has been taken up by the rice plant and not get the full benefit of the midseason N application.

Furrow-Irrigated Rice Nitrogen Recommendations

Jarrod Hardke and Trent Roberts

There are multiple strategies for fertilizing furrow-irrigated rice (FIR; row rice) successfully.  If you see “preflood” rate mentioned below, we mean the rate you would normally apply prior to flood if you were flooding the field.  The recommendations below are also based on rice in soybean rotation.

Hybrids

Work from base preflood rate of 120 lb N/acre on silt loams and 150 lb N/acre on clays.  Note that these strategies focus on early-season N management.  We still recommend 30 lb N/acre (65 lb urea/acre) at late boot in addition to the early season N strategies for hybrids described below.

Silt loam option 1:  starting at the 5-leaf stage, make 3 applications of 46 lb N/acre (100 lb urea/acre) spaced 7-10 days apart.

• Example: Day 0 – 46 lb N/acre, Day 7 – 46 lb N/acre, Day 14 – 46 lb N/acre

Silt loam option 2:  Apply half the recommended preflood N rate at the 5-leaf stage, followed by 2 additional applications of one quarter of the preflood N rate spaced 7-10 days apart.

• Example: Day 0 – 60 lb N/acre, Day 7 – 30 lb N/acre, Day 14 – 30 lb N/acre

Silt loam option 3:  An excessive preflood N rate (150% of standard) has produced optimal yields, but greater risk involved than split methods.

Clay soil option 1:  Apply half the recommended preflood N rate at the 5-leaf stage, followed by half 10-14 days later, followed by an additional 46 lb N/acre (100 lb urea/acre) 7 days after the 2^nd application.

• Example: Day 0 – 75 lb N/acre, Day 10-14 – 75 lb N/acre, Day 21 – 46 lb N/acre

Clay soil option 2:  starting at the 5-leaf stage, make 4 applications of 46 lb N/acre (100 lb urea/acre) spaced 7-10 days apart.

• Example: Day 0 – 46 lb N/acre, Day 7 – 46 lb N/acre, Day 14 – 46 lb N/acre, Day 21 – 46 lb N/acre

Varieties

For pureline varieties, at this time it is recommended to follow the approach of 4 applications of 46 lb N/acre (100 lb urea/acre) spaced 7-10 days apart beginning at the 5-leaf stage.  Some varieties with lower than standard preflood N rate recommendations may be able to perform with only 3 applications but will need to be monitored closely.  The 4^th application (sometimes the 3^rd) coincides with the midseason timing so there is not a need for an additional midseason application after your 4 applications are complete.

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.