USA
April 18, 2018

By Dr. Sunny Bottoms, Senior Technical Service Representative and Dr. Tim Walker, General Manager, Horizon Ag

Although cold fronts have kept up a pretty steady schedule the last month or so in the Mid-South rice growing region, resulting in planting delays for many farmers, there’s still time to plant rice and achieve strong results at harvest.

In areas that were fortunate enough to miss previous rains, rice was planted on any available dry acre in the last two weeks. However, the last widespread rainfall on Saturday, April 14, brought planting to a screeching halt. Now that we are in mid-April, you may be wondering about the optimal planting window. As a matter of fact, Dr. Jarrod Hardke, University of Arkansas Rice Extension Agronomist, referenced his date of planting trials in this past week’s Arkansas Field Notes. University of Arkansas date of planting data from 2013 to 2017 are depicted in the graph below.

Generally speaking, rice has the highest yield potential, and the least variability, when planted from March 15 to April 15 in the upper Mid-South. Rice yield potential is equally as high, however, when planted all the way out to the end of May, although yields can become more variable once April 16 arrives, as the graph depicts. Over the past five years, the most variable-yielding rice has been rice planted the first week of May. Yield potential is the lowest when planted in June. From the data in the planting window starting from April 16 and ending May 15, in 50 percent of the chances, rice was 90 percent of maximum relative yield or greater. Furthermore, 78 percent of the chances saw rice yield 80 percent of the maximum relative yield or greater. 

Since we will be arriving at the May planting window soon, allow us to expand on the factors contributing to variability in May-planted rice. In our opinion the largest variable for May-planted rice is summer nighttime temperatures, especially during July. May-planted rice typically reaches critical reproductive stages during the latter half of July. From 2013–2017, state average rice yields were about 400 lbs/acre greater when nighttime temps for July averaged below 74 degrees compared to those years where average nighttime temps for July were above 74 degrees. 

Bacterial panicle blight (BPB) is favored when nighttime temperatures are higher and there are no current control methods for bacterial panicle blight other than genetics and planting date. A quick review of average nighttime temperatures for Stuttgart from 1998-2017 indicated that seven out of those last 20 years had average July nighttime temps of 74 degrees or greater. The newer, top-performing Horizon Ag varieties – CL153, CL163, and CL172 – are rated moderately susceptible to BPB. Although they aren’t resistant to BPB, more yield stability is expected from these new offerings when conditions are conducive for BPB, and they are good choices as you’re looking to get your rice planted this season. 

In summary, the planting window is still very much open for rice. Continue to plant Horizon Ag Clearfield® varieties to help you optimize yields, control weeds and provide an end product desired in the domestic and export markets in the weeks to come.  

Website: http://www.horizonseed.com

Published: April 19, 2018