“At some point it can’t get any wetter, it can only get deeper.” The South half of Arkansas is feeling that statement this week. Torrential rains struck areas of east-central and southeast AR with places like Dumas seeing 18” or more. This week turned into one of crop and field destruction south of I-40 (not to mention homes and businesses), while rains scattered the northeast region.
Either way you slice it, by and large it’s another week lost for management progress on this crop. One could argue it’s one step forward in time, two steps backward in management.
Washed out and busted levees are the most widespread rice concern in heavy rainfall areas, and in all areas attempting to fertilize and flood aging rice is reaching a critical point. However, there are more rice acres that are completely submerged and need drainage quickly.
Mild conditions may work in our favor for managing these issues, but lack of pushing the crop forward will only push the harvest window further back. Temperatures appear ready to finally take off this week, increasing the need to manage this crop quickly to stay on track.
Managing Rice Submerged or Flood Lost
With all of the rain experienced in south AR this week, the questions certainly turn to rice survival. Rice is semi-aquatic and tolerates a flood but does not like deep water and submergence. It all depends on the overall conditions, but the condition of the floodwater is a key component.
Rice News on AgFax
While there are no real management recommendations other than ‘get the water off’, here is some of what you can expect on rice survival which may influence your efforts on which fields to work hardest to remove water from.
Younger rice, still in the seedling / tillering / vegetative stages, can survive for long periods of time under submerged conditions. When conditions are mild, and the floodwater is cool and moving, we’ve seen rice survive submergence for a month. However, we’ve also seen rice die in a week when floodwater conditions are deep, muddy, and stagnant.
Older rice at midseason or around joint movement / reproductive growth is more sensitive to being submerged. If submerged for less than 7 days, it generally survives but there may be issues with it laying over as the water goes down and need time to stand up. In the 7-10 day window, survival can be a coin flip. As we approach 10 days or more of submergence, the outcome is usually bad and plants die.
Keep in mind these comments are based on years of observations of flooding events that have occurred and have been the most common responses, hopefully most fields will beat the odds.
Fields that had already been fertilized and flooded, but now have washed out levees, pose another problem. Some will be straightforward repairs, but others are extensive. Whether you have lost nitrogen is a highly variable situation.
If you’ve been flooded for around three weeks then any N loss will be minimal or nonexistent when you reflood (you haven’t lost N just because you lost the flood). Just get the flood back on as soon as you can and keep going to avoid allowing fields to dry too much and stress in early reproductive stages.
If you’ve only been flooded a short time and after repairs will be reflooding prior to 3 weeks since initial flood, N loss could happen. However, it is advised that you do not automatically add N at this stage. You are far better off to reflood and then monitor the crop as it continues to progress. Unnecessary N applications will only increase our cost and exaggerate management issues.
After the flood has been reestablished monitor for potential N deficiencies or use the GreenSeeker to determine if and when more N may be needed. Work has shown that rice yield can be recovered or increased with midseason N applications as late as 3 weeks after panicle initiation (green ring).
What to Make of ALS Flashing
Rice “flashing” from applications of ALS herbicides (such as Permit) is nothing new. Often it occurs earlier in the season but in these cooler, wet years it continues to show up even now. As in the past, blame the cool, wet, overcast conditions. The plants just aren’t growing off and making it through the herbicide, but they will given time.
The strange yellow patterns, sometimes involving compaction from wheel tracks, are the giveaway to this issue. The lack of a consistent pattern is typical of the ALS flash pattern. If the rice has been flooded, keeping a shallow flood will help reduce stress on the rice and let it grow out of it. In rare instances of severe responses we may have to let the flood drop back to a muddy state.