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Arkansas Rice Update 3-20-14
Author: Jarrod Hardke, Rice Extension Agronomist

March 20, 2014                           No. 2014-2

Dr. Jarrod Hardke and Dr. Bob Scott

Wait for it, wait for it…

We’re so close to planting time that you can almost feel it.  A few jumped the gun in the past week and put some rice in the ground.  Soil temperatures are still cold (~49°F on Friday) and look to remain that way for the time being despite some warmer daytime temps.

While some may not be happy about the rain last weekend, it’s probably just the slowdown we needed to keep us from doing things we shouldn’t (like plant rice).  Daytime highs in the 60s and 70s this week will be nice, but we could see another drop in temperatures this weekend.  Current forecasts show nighttime temperatures at or near freezing for much of the state early next week.

We certainly recommend planting early to maximize yield potential (Figure 1), but let’s not get ahead of ourselves.  Rice is very resilient and we can get away with a lot, but if conditions aren’t right for the rice to germinate and grow off then we have problems.

There’s nothing wrong with pushing the envelope, but let’s remember the economic bottom line.  Planting earlier may increase grain yields, but jumping the gun by a week may not necessarily result in a noticeably higher yield.  What it will likely do though, is result in an additional herbicide application, maybe a starter fertilizer application to shorten the time to flood, and the loss of efficacy of your insecticide seed treatment.

There’s still a lot of time left to plant early.  Let’s get the ground ready (for all crops) and be sitting on ‘go’ for when the time is right.  Right now the weather forecast is for somewhat of a ‘false spring’ this week.  Let’s focus on the field work and hopefully the next warm-up will be the real thing.

Figure 1.  Average Grain Yield by Planting Date (Week of Year) – from on-farm testing 2008-2012.

2014-2 Figure 1 Avg Grain Yield by Week of Year On-Farm 2008-2012

*Week 11 is usually the last week of March and Week 20 the first week of June.


Weed Control Begins at Planting!

We are lucky to have Command herbicide for rice in Arkansas at the moment.  The development of propanil, Facet, and now Newpath (also Regiment) resistant barnyardgrass is a definite call for alarm.  Although we have identified a couple of barnyardgrass populations with increased tolerance to Command, resistance is not yet a problem.

On the other hand over 1/3 (13 out of 30) of the barnyardgrass samples tested in the 2013 resistance screening program were tolerant to Newpath.  This represents a dramatic increase from the 7 out of 200 previously known to exist prior to 2012.

The best way to battle the development of resistant barnyardgrass with the tools we have today is to begin with a sound Pre-emergence program at planting.  This can be as simple as using Command PRE in either conventional or Clearfield rice.  There are benefits to using a residual ahead of your first Newpath application in Clearfield rice, such as easier POST timing to control red rice without worrying about grasses getting too big.

In addition there are new products like Obey herbicide from FMC that contain the same active ingredients as in Command and Facet.  This is the type of program I use when I want weed-free plots in my weedy research areas.  You can even take it a step further and go to a program like Prowl + Bolero applied delayed PRE – neither of these herbicides have documented resistance and this program is pretty broad spectrum.  I would put it out with Roundup just prior to rice emergence for example.

None of these residual programs will help you if you do not get lucky and get a rain or make your own luck by flushing them in immediately after application.  There are some new tools on the horizon for rice producers, but we still need to make the ones we have last a couple more years, so please make resistance management or prevention a part of your weed control strategy for 2014.

For more options for rice weed control see the MP-44 at your county Extension office or online at

Picture 1.  Rice in the ground in east AR.

2014-2 Picture 1

Rice Drill Calibration

Proper calibration of your drill is extremely important.  To help with this process, we’ve developed a rice drill calibration worksheet that you can download and use at home.  This worksheet provides answers to two questions:

  1. How much seed should I catch at my desired seeding rate?
  2. How many pounds of seed per acre am I planting?

Section 1 allows you to enter your drill spacing, target seeding rate, seeds per pound of the cultivar you plan to grow, and gauge wheel circumference.  With this information entered, the worksheet will tell you the number of seed you should catch from one drill row per wheel revolution or per row foot; and the weight of seed collected from one drill row per wheel revolution or per row foot.

Section 2 allows you to enter the same information as Section 1 but without a target seeding rate.  After you also enter the number of seed collected, the worksheet will tell you how many pounds per acre, seeds per acre, seeds per square foot, and seeds per row foot that you’re drill is currently set to plant.  A link to the spreadsheet online can be found here:


For help in selecting the appropriate seeding rate, please consult the RICESEED program online at:

The online program provides an easy way to determine your recommended seeding rate based on cultivar, planting date, and planting conditions.  For more information, please see the attached RICESEED Update for 2014.

DD50 Enrollment

Some changes have been made to the online DD50 Program this year.  Hopefully these and future changes will continue to make the program easier and more efficient to use.  If you have any questions, or suggestions for improving the program, please let us know.  You can access the online program here:

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

This information will also be posted to the Arkansas Row Crops where additional information from Extension specialists can be found.  Please visit the blog at


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

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

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