Title: Harvest Aid Tips in Rice (8-24-20)

Arkansas Row Crops Radio providing up to date information and timely recommendations on row crop production in Arkansas.

Jarrod Hardke: Welcome to Arkansas Row Crops Radio. I'm Jarrod Hardke, Rice Extension Agronomist for the University of Arkansas System Division of Agriculture.

Today I'd like to talk a few minutes about the use of harvest aids in rice. Particularly sodium chlorate.

This has really kind of somewhat increased in the past several years. We estimate that we're applying sodium chlorate anywhere from 30 maybe even 40 percent of acres. Receiving some kind of application of sodium chlorate to help with harvest, desiccate that upper plant material & lower grain moisture so we can get moved on with harvest. 

However there's been some conversation about perhaps some misinformation about what you can expect out of these applications & just to cover some dos & don'ts of this material. We're also covering it in writing in the 82120 Arkansas Rice Update. To verbalize a little bit of that here.

We're going to try to use this as a tool to help with harvest but also minimize your risk. So several things to keep in mind when trying to use sodium chlorate as a harvest aid in rice. One of the biggest things we've seen over the past few years, revisiting harvest aids. Kind of focusing on hybrids the last couple of years because a lot of other work was focused on varieties, so getting a better look at using them on hybrids. 

One thing that's remained consistent regardless from older data on varieties, to some newer data on hybrids, is that we really want to try to complete rice harvest in five days or less after a sodium chlorate application. Basically what we see is that when you get, obviously faster is better, but what we see is when you get kind of beyond that initial five days & you start getting out to seven days or more after an application, there's really a good chance for heavy dews or rainfall to increase the effect on milling. Basically causing more wetting & drying & phishering of rapidly drying kernels. 

You can also get into the further you wait the more excessive drying can occur on those panicle branches & possibly lead to some more loss of dropping of kernels through shattering. In that way & even further taking it is actually starting to shut down those entire plants if enough time goes by which can make them collapse & increase lodging. 

There's definitely instances out there where folks have seen that they've been able to wait as long as seven days or I guess in some cases a couple of more, not really seeing any dramatic impacts. Those are going to be the exception not the rule & you can say that you kind of got away with something there but at the end of the day you can say you didn't really see a negative impact from that but without a check or a control in place it's going to be impossible to know whether or not, you lost five bushels or a couple points of milling, or both. But there's something to that effect out there so it's kind of hard to know. But those side by side comparisons, & research we've seen, where that risk is very real & at times can lead to some substantial losses when we've waited too long.

A few other points, we currently recommend something that really hasn't changed from the other recommendations is do not salt varieties until grain moisture is below twenty five percent. In the case of hybrids we don't want to salt until grain moisture is below twenty three percent. Anytime we've done the work where rain moisture's been twenty three to twenty five, there's some increasing negative impacts that could come into play. Again, all of these negative impacts are exaggerated the longer you wait to harvest, so that big key is still being harvesting in a short amount of time. 

On the other end of the spectrum, once grain moisture gets below eighteen percent, we generally recommend to no longer make a salt or sodium chlorate application to the rice. For medium grains, that for me is really going to be an absolute cutoff, especially for something like Titan that is earlier maturing & dries down a lot more rapidly than say Jupiter which tends to really really drag out. Long grains, you might be able to keep below that eighteen percent moisture mark, but you really need to start harvesting almost immediately because that grain moisture again is going to fall very rapidly in the plant & potentially get over dry very fast. But we don't always see a huge impact vs salting or not around that eighteen percent to maybe just below the mark. 

The lower the grain moisture at the time of application, the more you should maybe consider using a lower rate of sodium chlorate. A lot of the products out there now are five pound of sodium chlorate per gallon so a one gallon rate will give you five pounds. That's going to work pretty well & look good, especially across the higher moisture rice. If you are going to play with still making some kind of application to desiccate that upper canopy, as you're approaching lower moisture ranges, you might consider using a half gallon rate which would give you two & a half pounds of sodium chlorate. And that's going to hopefully decrease the risk of over drying the rice. Now some older work that was done comparing those roughly those same higher & lower rate didn't show a dramatic difference. Sometimes not even a significant difference between the rates in terms of what it did for reducing grain moisture. So you should still get some of the same impact of the lower rate, but again we're trying to reduce our risk by using that lower rate & making sure we don't over dry things.

So again, looking at not starting until a little bit lower moisture potentially with the hybrids & be careful with reaching a point where you stop salting. My overall goal is to use the sodium chlorate as a harvest aid, a tool & in a lot of situations on rice that is just not quite ready so maybe we can use the sodium chlorate to get it started & by the time we get through some of those initial acres, we can then move into rice that the moisture's already naturally falling lower & in a range where we can go after it. And avoid the cost & additional risk of sodium chlorate applications out there. Definitely been a little bit of unevenness to the heading & maturity of the crop out there. That's going to play a role in your decision making this year of when or if to make a sodium chlorate application. Again leaning conservatively. You're fairly uneven out there & uncertain about later maturing areas in the field & we're going to want to lean down & get further & further away from that twenty three or twenty five percent top end to try to make sure we kind of get everything in the more reasonable window that's it's a safe application to make.

So never an easy decision to make but something we just need to be careful & mindful of when we make those applications. That we're not going to do any more harm than good.

If you have any questions, feel free to reach out to me. I'll be happy to visit with you about more in-depth on some of that work that we've done & certainly any other questions that may come up surrounding the use of harvest aids in rice. 

With that, once again Jarrod Hardke, Rice Extension Agronomist with the University of Arkansas System Division of Agriculture. Thank you for joining us once again on Arkansas Row Crops Radio. See you next time & have a rice day.


End notes: Arkansas Row Crops Radio is a production of the University of Arkansas System Division of Agriculture. For more information please contact your local county extension agent or visit uaex.edu.