Dr. Jarrod Hardke and Dr. Gus Lorenz
May 6, 2016 No. 2016-08 www.uaex.edu/rice
Crop Outlook / Progress
The windows of progress have been short and sporadic this spring but largely in our favor. Plant, spray, rain, repeat. We’ve been fortunate to get nearly 90% of our rice crop planted before May, a rare occurrence.
The more impressive part is the optimum and even above optimum stand counts we’re seeing from all this early planted rice. While we normally have to deal with managing below optimum stands on a lot of early-planted rice we’re actually set up to maximize yield from the jump – a great turn of events for 2016.
The few negatives are the start of some development of seedling disease impacting stands in a limited number of fields. Fortunately the optimum stands already achieved are keeping stand loss from being too severe.
We talked a little about drift complaints coming up last week. There’s reason to believe that we could battle drift on rice even more this year than in previous years. A lot of early planted rice means that we could be hitting midseason (reproductive stage) rice about the time a lot of POST applications in soybean are being made. Drift from glyphosate any time after midseason can have devastating effects on rice yields and it doesn’t become apparent until rice starts to head. When it comes time, there doesn’t need to be any glyphosate going out by air with rice around.
There have been plenty of issues this past week: seedling disease showing up, washed out levees in need of repair, flooded out fields, and dried out fields crusting over needing to be flushed. Rainfall in the forecast for next week will be good for some and terrible for others – you could say just another week in Arkansas rice production.
Standing Water & Newly Planted Rice
Where rice has just been planted and rains cause extensive flooding there is plenty to be concerned about. As a rough estimation, you have between 6-14 days to get the water off to ensure that you salvage the rice. If water stands longer the odds are not good that you’ll end up with a stand worth keeping. Rice will emerge through soil or water, but not through both.
Fig. 1. Beautiful rice growing weather.
Preflood Nitrogen Management Tips
A good piece of advice I once received: “to be early is to be on time, to be on time is to be late, and to be late is to be fired.” If you have rice just getting ready to go to flood and an unfavorable forecast, it might be best to go ahead and pull the trigger.
For fields reaching the ‘ready to fertilize and flood’ point right now – there is a decision to be made. The rice is at the right stage and is ready, but a lot of it is not very tall. Soil is dry or drying and there is a week full of rain ahead of us. As long as the rice is otherwise healthy and you can avoid putting too deep a flood on it, go for it. If we end up in a rainy period we could very easily end up on the wrong side of the window and be forced into making the best of a bad situation as we’ve done a lot the past few years.
We always have a couple weeks for our optimum preflood N window. However, if we get dry soil and the upcoming forecast is full of rain (like we do now), it might be time to go for it. Use the DD50 program as your guide http://dd50.uaex.edu.
Fertilize on dry soil if at all possible. This is the most efficient means of N fertilization in rice. Treat urea with an approved NPBT containing product such as Agrotain or Limus and flood as soon as possible.
If you reach the end of the window (Final Recommended Time to Apply Preflood N in DD50) and you have to apply on muddy soil, you must treat urea with NBPT, and it would be wise to increase the N rate by 20-30 units to account for N loss associated with these applications.
As a last resort N applications can be made into standing water, but they should only be made in small shots – known as spoonfeeding. This is extremely inefficient and often not very economical, but is a last resort.
Do not, for any reason, apply the entire large preflood N amount into standing water. N loss is too great in this situation – often you wouldn’t be able to tell the difference between where it was applied versus where no N was applied.
Fig. 2. March 22 rice planting date study fertilized and going to flood today (5/6).
Rice water weevil numbers are a concern this year. With the large amount of acreage planted early and the long time to crop emergence, insecticide seed treatments are likely to be playing out.
Much of the rice going to flood now or in the next week or two has been in the ground since mid- to late-March – over 30 days. Once it’s been 30-40 days since planting, CruiserMaxx and NipsIt insecticide seed treatments are not going to hold RWW. Dermacor will still be working.
As a result, immediately after flooding it will be necessary to scout for RWW leaf scarring. If scarring and adult activity are high a foliar application of a pyrethroid like Mustang Max, Karate Z, or Declare might be called for.
So what is a lot of activity you might ask? If 50% of new leaves have scarring and adults are present consider a foliar application. Remember that timing is critical on the application – it must be made within 5-7 days of putting on the flood. If it’s later than that, our studies indicate you may as well keep the insecticide in the jug. Your only option then is to drain the field until the soil cracks to prevent weevil damage. Most growers aren’t crazy about doing that as it’s costly and may impact weed control and fertility.
If RWW levels are high this year you will need to get out there and scout those fields. Remember if you used Dermacor it will still be active. It is much less soluble and binds to the seed a lot more than the neonicotinoids (CruiserMaxx and NipsIt). So if you have Dermacor on the seed you are probably still OK. Dermacor doesn’t slow down adult scarring as much as the other seed treatments, so don’t assume it isn’t still there if you do have scarring on the leaves from adults.
True Armyworm activity has been observed in a few fields this year and rice fields should be scouted for developing infestations. Use common sense on deciding whether or not to treat; just the presence of worms is not enough to treat, but if they are causing substantial defoliation in sports or edges of the field then a treatment might be justified. True Armyworms are leaving wheat fields and are on the move. If you have wheat next to seedling rice fields be on the lookout for movement into the rice.
Fig. 3. Rice struggling to emerge through crust – flushing needed to establish stand.
DD50 Program is Up and Running!
The DD50 program can be found at http://DD50.uaex.edu. Enroll fields now to help with timing most major rice management practices.
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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.
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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.