Clearfield rice variety, hybrid score well in Arkansas fields

I started calling around the last couple of weeks trying to get a handle on how Clearfield 161 and the new hybrid Clearfield XL8 were yielding. It did not take long to figure out that they were having another good year. But then again, most rice yields that I am hearing about are pretty good.

I will have to defer the proverbial good or bad year question to my agronomy counterpart, Chuck Wilson. However, in the case of Clearfield rice yields, it is important to remember that this is only the second year of full market availability for this rice (three if you count the 24C year). Having worked on the development of this technology, I must admit I am impressed with how well it has done.

A few things have gone right for Clearfield. First, both this year and last year started off wet. I cannot stress enough how important good moisture is for controlling red rice and other weeds with Newpath. Some people learned a little more about that this year, but in general, performance of the herbicide was good.

Many growers that I spoke with used a reduced or full rate of Command pre ahead of the sequential post program with Newpath this year; others used a reduced rate of Facet or other appropriate tank-mixtures to round out the weed spectrum of Newpath.

For the most part I feel confident that growers have figured the Clearfield system out from a weed control standpoint after two years of use.

Probably the next factor for success has been yields. Clearfield 161 has the yield potential of Cypress. Clearfield 121 and 141 historically can yield around 160 with fluctuations as high as 190. For the last two years these varieties have pretty much hit the maximum.

Not everything has been perfect. The number one question about Clearfield I was asked this year was, “How late can I put this stuff out without hurting the rice?” The problem was late-season red rice escapes.

It is important to point out that Newpath is currently labeled for a maximum of 8 ounces per season. That is two 4-ounce applications.

However, we had several studies this year in cooperation with BASF Corporation looking at late applications of Newpath and at a new herbicide (Beyond) that may be registered for use on Clearfield rice. So, far we have not observed any injury on either Clearfield 161 or Clearfield XL8.

We have now applied these herbicides all the way up to seedhead emergence and flowering. It has become clear after this year that one more herbicide option is needed to clean up subsequent flushes and late-season escapes. I hope that this is a minor need and does not become the standard.

I think it is the right thing to do if we can get a label to avoid out-crossing scenarios.

I was impressed this year with the consistency of the Newpath programs that I saw. This includes everything from barnyardgrass control to morningglory suppression. That is not to say that Newpath stood alone; there were a lot of tank-mixes. But everywhere I went this year, no matter what field I was looking at, the farmer or consultant would say, “Hey do have a minute to come over here and look at this Clearfield rice?”

Also, these fields have remained relatively clean through harvest!

A word of caution going into next year — at the beginning of this article I mentioned the moisture we have had the last couple of years. I still strongly encourage you to consider your ability to get water to a field before you make the decision to grow Clearfield and use Newpath herbicide. In a dry spring, we may find a totally different situation with Newpath performance.

Also, read the label carefully when it comes to the sequential post program. I have been told that the application timings will be adjusted this fall. In our trials, the best performance from a sequential post program has been to go out with the first shot at two- to three-leaf red rice and then come back 10 to 14 days later with the next.

Also, an upfront application of Command has proven to help the program this year.

From what I am hearing, a lot of folks are planning on using Clearfield next year or increasing their planted acres. Seed availability may be an issue. Seed booking for 2004 has already begun.

Bob Scott is the University of Arkansas Extension weed specialist. [email protected].

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