Episode 12 - Fertilizing & Flooding Early Rice

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. My name is Jarrod Hardke, Rice Extension Agronomist for the University of Arkansas System Division of Agriculture. 

Today let’s talk a little about fertilizing and flooding early rice. The earliest planted rice out there in the state went in very very late March, very beginning of April. Some of that has made it all the way to the 4 to 5 leaf stage. There’s probably a little larger percentage of rice that went in the early part of April that’s now 3 to 4 leaf and then ya know, even more rice now as we finally made some greater headway in planting a bunch of rice that’s really at the 2 to 3 leaf stage. In a lot of these situations with the rains that we’ve had a lot of these fields are clean. Our residual herbicides have worked very well, a number of them were on the cheap side so far from herbicide input standpoint and you guys are looking at when can I really take this rice to flood and moving on and try to stay cheap with that in mind versus waiting with the weekend into next week rains that are coming and suddenly pushing us into what may be a later potential or having to come back in with another round of herbicides and maybe not just residuals but maybe even some more costly post-emergence herbicides to try to clean up things that have then broken through after those rains. And in a number of areas right now those soils are getting at least at the very surface getting pretty dried out at the moment where we have the potential to run some nitrogen fertilizer right now. So really the thought process is if we can find dry ground and rice that's large enough, we probably need to try to go with it right ahead of this rain. There's certainly a lot to consider if you've got 4 to 5 leaf rice, a lot of that is only 4 to 5 inches tall. I'm more worried about the fact that it's 4 to 5 leaf than I am the fact that it's 4 to 5 inches tall. Now, zero grade fields or straight levee fields on a half tent to a tent, certainly they make it much easier to say “go ahead and fertilize and flood up” and manage a shallow flood. The steeper the field, the more stacked the levees, the more contoured, the greater the slope, the more that’s going to be an issue with shorter rice, but keeping in mind that if rice is 4 to 5 inches tall and you can shoot for that initial flood depth set of 2 to 4 inches deep. 2 inches deep on the top of the patty, 4 inches deep on the bottom. Yeah, it's going to be a little deep on the bottom, but as soon as that first slug and head of water kind of gets by it’s within a few days to that first week that rice is going to take up that fertilizer, that nitrogen and begin to take offtake off while at the same time our water level is going to be kind of simmering back. Now, we do have some rainfall coming so that's probably again going to help us flood some of these fields up a little more uniformly and incorporate some nitrogen and maybe we can get through some of that and finish topping off fields in that way. The shorter the rice gets and the earlier it is the more emphasis we obviously have to have on kind of staying away from going too early on fields that we can manage the flood depth, that’s its absolutely going to be too deep and too tall. 2 to 3 leaf rice it's only 2 to 3 inches tall, the bottom sides of patties I'm obviously going to put under with an initial flood attempt unless that’s a zero grade or a very shallow slope field so I’m probably going to avoid those. Now, having said that where you can do it, we’ve got data over recent years that show when we can put, ya know, with 2-inch flood with 2 to 3-inch rice. We’ve fertilized on dry ground at that time we had top in yield potential by going then and we can lock that nitrogen in. Though, I will say if we're going with rice that small, I would consider just a slight increase in pre-flood nitrogen, so 10 units or 10 lbs. of nitrogen breaker increase something like that and that’s just trying to offset the little bit greater time nitrogen is going to be sitting in the soil waiting for the rice to take it up as it grows and begins to consume more and more so were just trying to balance that a little bit. That hasn’t been something we’ve looked at very closely, just something knowing the soil and environmental conditions that may be present that we may need to be concerned about. But, again, the flood depth management is a very key part to this but we can’t let this rice get too far along. A lot of that rice that may have been planted at the very end of March, emerged the first or second week of April and a lot of our final recommended dates to have nitrogen incorporated by are coming up in the next few days to the end of next week really depending on the maturity of the given cultivar and the ground and things that were planted in the early part of April that didn't come up until about the third week of April. We're still looking at those final dates we wanna have nitrogen out and incorporate it with the flood by the end of next week around the first of June to move on those so as were clearly gaining steam here and going to very quickly find ourselves behind, particularly if we don’t start taking some of this 4-leaf rice or 4 to 5 leaf rice on to flood and get it moving. Certainly, I want it to look healthy. A lot of rice has dramatically improved in the last just several days to week with a little bit more sunshine and more consistently warm temperatures so its otherwise healthy and in good shape in that size, we need to get it moving and get it gone. Again, if its not always a manageable situation, we can wait but prepare for a little bit more risk. Again, with ending up with the late side of getting it out there and some potential yield reduction and some possible increase in expense due to additional herbicide applications. I’m trying to focus obviously on the rice management. There’s still a lot of things going on for a lot of guys still trying to plant some rice, some guys that are done with rice trying to plant beans. I’m always a strong proponent whichever crop is in the ground and growing needs to be managed, that’s gotta be my number one priority and then continue, if that means not getting as much planted right now because I’m gonna give up yield by not having timely management on what’s in the ground. And, remember, a large amount of our investment in rice is already out there sitting there waiting on us. Certainly, the next biggest input is that pre-flood nitrogen fertilizer. That's gonna be a big one but we can go ahead with it and that's the majority of our inputs in there for rice so we need to try to get them on time and out there correctly and when the rice is gonna need it to maximize yield. The later we wait to pass that pre-flood nitrogen timing, the more your yield potential just begins to decline and we can't get it back at that point. So, again, not every bit of rice is out there or is in a field situation where its ideal to start moving forward at this point in time but where you've got fields and opportunities where they're clean, you've got dry ground and remember in theory we got a few more days here before those rains set in. This rice is just gonna get taller and a little bit older in the meantime. So, if we can start getting that fertilizer out there and maybe even another round of residual herbicides with it and then have the rains come in and help us out and flood up, we're gonna be a long way toward an earlier harvest and we hope a more efficient one and help us manage these fields and the other ones to come just a whole lot better.

So, that’s kind of a quick recap on fertilizing and flooding early rice at this time. And, if you have any questions please reach out cell phone, email, you name it and we’ll try to help you out. Once again, this is Jarrod Hardke, Rice Extension Agronomist, and thanks 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