Episode 1 - Rice Harvest Aids with Jarrod Hardke 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 Id like to talk for a few minutes about the use of harvest aids in rice, particularly as it relates to hybrid rice. Previous research with the University of Arkansas System Division of Agriculture has led to recommendations for varieties, pure-line varieties, such as Diamond, CL153, that we do not need to make harvest aid applications (primarily discussing sodium chlorate or commonly referred to as salt) we don't need to make those applications until rice has fallen below 25% average grain moisture, and we need to stop making applications once we fall below 18% average grain moisture. Since that work was done on pure-line varieties 10 or so years ago, we now grow a significant acreage of hybrids, so in the past few years, we have revisited some of the sodium chlorate application work on hybrids, more specifically on XP753. What that work has shown us has largely reconfirmed some of the previous research that was done on varieties. However, it has added perhaps a little bit of nuance to those recommendations. Ultimately the old research and the new research does emphasize one important point. Harvest timing after application is what's most critical, so once we have made a salt or sodium chlorate application we really need to harvest that rice within about four days. Maybe you could technically stretch that to five. I probably wouldn't recommend it. Four to five days is really what we need to do to get it out. Every time in the data, whether old or new, when we take up to seven days or greater to harvest that rice we see significant negative impacts in terms of grain yield, milling, you name it, it ends up pretty ugly to look at. So ultimately in terms of rate, the most commonly used products out there today are five-pound materials, so a gallon contains five pounds of active ingredient sodium chlorate. Generally, folks are running either a gallon or half-gallon rate, so anywhere from two and a half pounds to five pounds. Surprisingly, there's not a huge amount of difference in the response to those two different rates, except to say that the higher rate, the five-pound rate, seems to give a much more consistent plant response. So that's a positive thing. The lower rate is certainly going to lessen the response so the moisture drop you get may not be quite so dramatic with the reduced rate, however its again much more inconsistent. You can still get some similar moisture drops, just not quite as uniform, so the recommendation is probably to lean toward the higher rate just for uniformity if were going to use sodium chlorate. But if we're trying to minimize negative impacts then backing off the rates is certainly going to help with that, but its also not going to desiccate as much or as fast. What most of the work has shown is that if we can harvest within three or four days after application, then we're probably not looking at much of an impact in terms of grain yield. If you're looking at varieties, then again 25% grain moisture or below you're probably fine, however for hybrids, again if you picture hybrid panicle being much longer than a typical variety panicle, so you have a much wider range of individual kernel moisture on that panicle for a hybrid and so what the data has ultimately shown is that those hybrid panicles, we really don't get a more uniform response in terms of not having a loss of grain yield or milling, until we start to get below 23% average grain moisture. And again, were attributing that to being the range of moisture on the panicle being that much greater. On the bottom end, 18% may be a pretty conservative kind of baseline cutoff. However, you've got to remember that even independent of making a sodium chlorate application, when we allow long-grain rice cultivars to start falling consistently below the 16% grain moisture getting down to 15 or less that we already have real potential for reduced milling yields. When we begin to make sodium chlorate applications below 18%, we do start to bring into play the potential to over dry that grain and have head rice yields that are not necessarily specifically the cause of or result of the sodium chlorate application, more result of over-drying. We do want to avoid that as well. Again, a little bit more conservatively than what our recommendations have been for variety is really 23% to 18% for the hybrids versus the 18 to 25 for varieties. However having said that, with some of the different varieties available now, were moving in to work this year to revisit some of the current varieties to ensure that we don't need to also reduce that top-end level to being below 23% on those. For the moment, continue to exercise a little caution on those varieties as well until we get some additional supporting data on these newer ones to make sure we're not giving something else up. At the end of the day, if we're in the 18 to 23% moisture range, we are not and we can harvest in three, four days after application, then odds are very low that we're going to see a penalty from a grain yield standpoint or a milling yield standpoint. If you look at some of the date and figures that we've put out recently, and we've certainly stated this in writing as well, you can see a slight drag in yield, not significant but a slight drag in yield from the treated plots to the untreated check control plots. We really attribute that again to the fact that we cannot manipulate the combine from plot to plot as adequately as what we would be able to dial in a commercial combine in a field and really optimize that harvest potential to minimize loss and issues through our airspeed, reel speed, ground speed, everything be a little bit more uniform. It's very difficult to do when you're going from a dryer plot to a much greener wetter plot. One to the next to really make those changes and optimize harvest so some of that slight drag is always going to be in place as a result of just the nature of trial work. So going forward, certainly use sodium chlorate applications to your advantage. Be careful going forward with the current fall conditions. What kind of fall conditions move into the end of August, 90 degrees north wind, very sunny. Grain moisture is going to drop very rapidly on its own, and a lot of plants should be begin to senesce, so watch out making applications when the grain moisture is already dropping very rapidly. But with that, use sodium chlorate to your advantage if it can help. Avoid it and save the cost if you think you can otherwise, and best of luck with harvest. Thank you for joining us on Arkansas Row Crops Radio. 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