We’re still dealing with the aftermath from the flooding events in South AR and that’s driving most discussions these days. With the hot and dry conditions, we’re at an odd stage where we’re trying to drain and salvage rice but also needing to keep rice irrigated as the crop shifts into reproductive growth.
Beyond that, it has been a very busy week throughout the state with the warm and dry conditions. A large amount of rice that has been late getting to flood is now finding its way there.
Remember to keep with recommended preflood N rates even if delayed, and for varieties, be mindful of waiting to apply a midseason N shot until at least 3 weeks, preferably 4 weeks, after preflood N is incorporated. This allows us the greatest chance for N uptake, which can still be maximized well after ½” internode elongation.
Given how warm and dry this week has been, expected rainfall this week may actually be welcome. We’ll hope that it’s a light round and that the system in the Gulf continues to spin off to the east and keep us out of large rainfall events.
Managing Rice After Submergence and Flood Loss
While in many instances we have no control over how deep much of this water is or how long it will stay, there are some general expectations of rice response to it.
Rice near Green Ring or Later
Large rice near midseason or later is most sensitive to submerged conditions. When rice is submerged for 7 days or less, it often survives. However, when submerged for 7-10 days it starts heading downhill fast with plant death increasingly likely and when submerged 14 days or more we typically see complete crop loss.
AgFax Weed Solutions
These are based on general observations from previous years. The heat experienced since last Thursday on mostly stagnant water has sped that timeline up and rice is surviving for fewer days in some cases.
The goal is to get the rice out of the deep flood but still keep a shallow flood to a muddy state. This will allow the plant to catch its breath, rid itself of excess water, and possibly stand back up but also prevent it from drying stuck to the ground.
The larger the rice, the less likely it will stand itself back up after several days completely submerged. Unfortunately, you can often tell that it’s not oing to make it by the obvious rotting tissue smell as plants lay over when the flood goes away.
Rice from Seedling to Preflood Stage
Smaller rice at seedling to early tillering typically survives much longer. However, under deep submergence in hot, stagnant water, it can go quickly as with larger rice. As the rice comes out of being submerged it has a much easier time standing up and similar steps should be taken to prevent it from drying stuck to the soil surface.
**Note that it is probably best for rice recovery to completely remove any flood at all, but as the ground begins to firm we need to be chasing a flush across the field to keep rice from sticking and help it remain healthy. It is a delicate balance but considering chasing a flood down the field just days after the unwanted flood leaves the field.**
Some rice that was submerged but not too deep has stretched trying to reach out of the water. This rice can still do well but will maintain that extra height to harvest and will be prone to lodge early. Keep in mind that depending on the degree of stretching, flood management changes.
When rice has “stretched” due to submerged conditions it will be taller than normal and keeping the field flooded will help the rice stay upright, whereas removing it now may make it go ahead and collapse. In some cases of minimal stretching, we could help ourselves with the removal of the flood to stimulate root growth to handle the taller plant. Farmers can use a trash pump for dewatering tasks that have high solid content such as leaves, sand, sewage, twigs, sludge, and mud. You can visit https://homerdiy.com/best-trash-pump/ for a review of the best trash pumps on the market.
This is a difficult decision that has to be made on a field-to-field basis and previous experience looking at the height of rice in relation to the typical height based on the relative growth stage (DD50) can be very helpful.
Nitrogen Management Considerations
If submerged fields had already received preflood N, then farm as normal and watch the crop for changes that would suggest inadequate N. When the rice has not received preflood N, attempt to dry the field to fertilize and reflood as normal.
If conditions dictate the rice needs to remain with some flood to ensure full recovery (to prevent lodging or sticking to the ground), then keep that flood present and begin spoon-feeding N, but only start applications once new green growth is apparent.
Field levee issues are another concern. Some fields that have been submerged have levee issues, and many fields weren’t submerged but have major levee issues. The comments generally remain the same about managing levee loss. If you had preflood N out prior to levee breaks, remember that flood loss itself is not a major N loss mechanism.
It is the reflooding later that could trigger major losses. If you are restoring the flood and it has been 3 weeks or more since preflood N was incorporated, then the risk of N loss is minimal to non-existent. If you are reflooding within 3 weeks of having originally gone to flood, then there is a risk of N loss.
However, in all of these situations, unless the crop has taken on a noticeably N deficient look, do not apply additional N at this time. Potential N deficiencies can be addressed during midseason. Many years of work have shown that when additional N is needed, applications as late as 2 weeks after ½” internode elongation (IE) can still provide maximum yield response.
Do not add extra N just assuming that a significant amount was lost as this can continue to increase rice height and exacerbate the stretching from submergence, almost guaranteeing lodging prior to harvest.