It’s been nice to see some tractors on the move this week. Fieldwork has been has been spotty and scattered, but it’s nice to see something happening for a change. However, some of that ground has still looked a little wet so early-season compaction issues may show up in the form of weak stands and increased herbicide injury.
The first fields have been planted this week with some rice planted around Hunter and now near Lake Village with more planted in north Arkansas today. Soil temperatures are still cool, but that’s nothing new for this time of year. Seed will sit in the ground for a while before anything happens though.
While temperatures are forecast to steadily improve, there are once again several rain chances in the extended forecast. Currently the rain expected this weekend is now turning into rain throughout next week. Or if you look at a different model there is a break for a few days before rain chances crank up again next Friday. We still have time to get things done, but the opportunities to say that are running short. One good window and the outlook will change quickly.
Rice Germination Rates
In recent years, we’ve grown accustomed to rice seed germination rates around 90%. This year, some rice seed was impacted by conditions prior to harvest in 2018 which did lower some germination rates.
AgFax Weed Solutions
At this time in 2018, certified seed tested showed an average germination rate of 92% on 794 samples (range 74-98%). This year the current results are an average germination rate of 84% on 573 samples (range 0-97%) [personal communication, Mary Smith, ASPB].
Seed bags may not always be labeled with the exact germination rate. As long as they meet the minimum of 80% that may be all that’s listed on the bag, though they may have actual germination rates much higher.
All this is to say that you may want to consider some slight increases to seeding rates to ensure adequate initial stands are achieved.
Seeding Rate Recommendations The RICESEED Update for 2019 can be found here.
Our recommendations remain to use a baseline (starting) seeding rate of 30 seed/ft2 on loamy soils and 36 seed/ft2 on clay soils when planting varieties.
For hybrids, 10 seed/ft2 for loamy soils and 12 seed/ft2 for clay soils. Adjust these rates upward depending on soil conditions, planting date, and location in the state.
Optimum yields can be achieved at lower seeding rates, but the goal is to achieve a stand of 15 plants/ft2 with varieties and 6 plants/ft2 with hybrids. Plant the seed necessary to achieve a uniform stand at these stand densities.
Planting Date Studies
We’re not yet into what we consider the optimum planting window, but the southern half of the state is into the window where we know we can make rice. Results of 2016-2018 planting date studies at Stuttgart can be found at the link below, which show late March through mid-April as being optimal time to achieve near maximum yields.
2016-2018 Planting Date Studies. We have begun planting date studies at Pine Tree as well, but that data is currently limited. The quick take-home message at that location is lower yields at the late March and early April planting dates in 2018.
This is likely due to the seed sitting in the ground for 30+ days prior to emergence, but more data will be collected to confirm if this yield trend continues. Yields improved significantly at the late April and early May planting dates.