Dr. Guy Collins, NCSU Cotton Specialist stops by and we discuss the cold, dry start to Cotton 21. We talk about what growers should be looking out for to determine the need to replant, how to manage cotton that has already emerged, and how to move forward the rest of the cotton planting window.
Dr. Guy Collins, NCSU Cotton Specialist stops by and we discuss the cold, dry start to Cotton 21. We talk about what growers should be looking out for to determine the need to replant, how to manage cotton that has already emerged, and how to move forward the rest of the cotton planting window.
Welcome to crop sense presented by North Carolina cooperative extension. I’m Jacob Morgan a field crops agent with North Carolina cooperative extension. today we have Dr Guy Collins North Carolina state university extension cotton specialist with us. Good morning Dr Collins can you tell us a little bit about yourself. Good morning good to be on the podcast today. As you mentioned I’m Guy Collins, I’m a cotton extension professor with NC state university. i work very closely with Dr Keith Edmisten, also a cotton specialist with NC State. My job is primarily extension work and on-farm research and Dr Edmisten does more on small plot research on stations and has teaching responsibilities and all that too so collectively both of our programs are not redundant but we work very closely together and for the betterment of growers and both have heavy heavy extension responsibilities. Thank you very much, so first off Dr. Collins can you give us an idea of how much cotton has been planted so far across North Carolina. Yeah it varies, I’ve talked to some growers that are 100% done and I've talked with a few that have yet to even begin and most growers I would say are 30 to 40 percent done but i would say statewide we're probably about half planted at this point. Okay so starting in April, the eastern part of the state got mighty dry and this past week we've had at least five days with low temperatures in the 40s. So what effects do these dry soils and these colder temperatures have on cotton germination. Well we have two different issues there so with dry soils I'll address that first. When we start running into dry weather you see a lot of growers tempted to plant deep trying to quote unquote chase moisture and we understand the incentive behind that but a lot of times that creates more problems for the cotton plant. So when moisture is already limited and unless it's immediately alleviated by a rainfall when we chase moisture like that by planting these really what happens is we plant it into marginal moisture so some seeds encounter moisture and are able to germinate and sprout but in many cases unless we get a rainfall pretty quickly it's not enough to get that seed to emerge. Or that seedling will emerge and other seeds don't encounter any moisture so then you'll have staggered emergence so when we plant deep like, that even if we are able to germinate all of them many of them may not make it through full emergence just because of the added stress by planting it too deep. It's got that much further to travel to completely emerge especially if you have soils with a tendency to crust that can be very problematic. The trick here this year is we also have cool weather as you mentioned. So what we generally recommend is planting in dry dirt planted shallow you know half an inch deep no more than three quarters of an inch deep and if that's in moisture that's great. If it's not in moisture the next time it rains it will be considered the planting tape and so and under most circumstances that's fine but when we get a rain when we have cool weather that can be problematic. So it's been very much a challenging year so to address the moisture situation we wanted growers to plant fairly shallow. That way it's not an added stress by planting it too deep when we do get a rainfall and hopefully you'll get more uniforms emergence. That way now with the cooler weather that's that has become problematic I mean we really didn't see this past five-day fail in the forecast until about last weekend or the beginning of last weekend and that is a separate issue. When we have night times in the 40s that that could be very problematic for cotton so when we plant cotton we look at heat unit accumulation within the first five days of planting with the assumption that cotton is planted into moisture sufficient enough to germinate seed. So of those five days the first three days are the most important. After the seed imbibes water you certainly don't want cool temperatures as cool as we've had down in the 40s at night within those first three days. Ideally we would have 50 DD60s accumulated in the first five days. Our cotton plant condition calculator is a real-time calculator that can help growers with those decisions and it gives the five-day dd60 predicted forecast at any given time for anywhere in north carolina for the day you use the calculator and the in the following day. It will also trigger different warnings and one that you'll see a lot this week is you've got nighttime temperatures below 50 degrees now had this stretch been a relatively short term in other words just a night or maybe two nights with these kind and we had warm soil we might have been okay. But what we've seen statewide is our soil temperatures are just dropping daily and that's to be expected when you have four or five nights in a row like this so it's not good for cotton.
So what do we expect for growers who planted through these colder temperatures to see and when should they start worrying about if they have an adequate stand or not. Okay well they can expect to encounter problems with either germination. In those cases you would dig down and see some seeds that were rotten some may have sprouted and probably i have a malformed root system. In the very best scenario if they do get good emergence it's going to be severely severely delayed with some slow growth. My gut feeling for growers that have planted here recently in the past few days they're probably going to have poor stands and would need to replant. So when we really assess that we would like to give cotton at least a week before we really know what we have under these conditions. It's going to take quite a bit longer so under normal conditions at 10 days after planning I start getting a little concerned about stands if it's not adequate and especially if I don't know the cause. At two weeks most of the time we're looking at a replant situation. Now for grower that planted in completely dry soil planted shallow and they have not yet had a rain they may not have to worry about anything but they probably want to dig down and scratch down to look at those seeds to see what they're doing. A lot of folks received a little light rain over the past two or three days at some point or another and that may be enough to germinate and see depending on how much they received. So with that said they need to really evaluate that but everybody else that planted in the moisture probably going to have severe stand loss and looking at if they need to replant. So within about 10 days after they planted they probably need to be out there trying to find seed, see if it's germinated, see what the stand is like. That's right i would be out there looking for sure at 10 days and probably two weeks time. For replanting or making a decision on whether or not and what do those numbers look like as far as you know percent of stand or or how many how big the skips are or what would be your recommendation on on where that number would be as far as when you should make a decision to this needs to be replanted or i think i can work with this with this stand that i have right. So Dr. Edmisten and myself are currently wrapping up some research where we collaborated with Dr Jason Ward and ] looking at this very thing. So our recommendations have historically been based on previous research that was done in the early 2000s and a lot has changed since then. Seed costs have changed varieties, yield potential, have changed and in the past few years the Seed companies have started charging for replanting Seed. So the cost of replanting used to be eight to ten dollars an acre or whatever cost for fuel labor equipment things of that nature. Now we're looking at a figure of about 35 an acre which is significant enough to get our attention. So with all these new parameters in mind we're just now completing some research and it looks like on average the threshold would be about 30 percent of the planted area occupied by three foot skips or greater. So if we can assess that and in this work we collaborated with Dr Jason Ward to see if we could versus manually, we could measure this with uavs and it turns out that we can. All that technology is still currently in development and that would make it a lot quicker and a lot more precise in terms of making these decisions versus going out there and manually measuring. But if it's accurate and we can assess it visually say about 30% of the planted area occupied by three foot gets more is generally the threshold where we would consider replanting. All right, so extension recommendations have been to get your cotton planted sometime before basically we try to say by may 31st. Sometime in that first week in June yields tend to really start plummeting at some point so in the first insurance date is may 25th which is basically 10 days from today. So what's the outlook for the rest of the cotton planting window? Can you talk about maybe some different strategies to help ensure better germination. Yeah okay well all right so we have 10 days before our first crop insurance deadline it depends on where you are in the state some folks may start back planning tomorrow um they may have acceptable nighttime temperatures starting tomorrow a lot of places will be Sunday before they can start back. Most growers that I’ve talked to have told me anywhere from three or four , or the five-six days if they can have a good run with cooperative weather and no major hiccups. So they could get this crop planted before the crop insurance deadline. So before this week we were not behind after this week i don't want to say we'd be behind but we can't afford any more lost time or we will be late. So as you said, the first deadline for insurance is may 25th and then you start losing a certain percentage per day until the end of may. Then after that your planted cotton is not covered by insurance so typically once we get into the first week of June it's very important that we focus on boll retention at that point. You know planting that late cotton loses its ability to compensate in time in terms of yield potential. So we can't really afford any losses due to insects and things of that nature. So preferably it would be irrigated land. We don't always have that option we can use that to our advantage to help retain bolls if dry weather is a problem later in the summer but outside of that we need to be extremely timely on insect management proper fertility not over fertilizing cotton and also with growth regulators. We don't necessarily need to be aggressive, but what we do say is we just need to be very timely if a pgr is needed. So timeliness is very very critical once we get into that first week of June and beyond the first week of June in most years the risk starts becoming too great to effectively plant cotton and any kind of hope for it but before that we can do it ideally like you said.
So some you know as you said some people, are done planting cotton and so some of this cotton was up and growing and germinated before this cool weather set in. So what are some concerns maybe thrips or some other concerns because this cotton is not really going to be growing or hasn't been growing this past week.
Yeah so if they planted before this cool snap hopefully we they had a good stand before the cool snap occurred, If the stand was in in development so to speak if his crop was still trying to emerge when we encountered this cool weather they're gonna need to evaluate it once we get on the other side of this maybe towards the end of next week at the latest and make a decision on replanting if they don't have good emergence. But let's say they had a good stand established before this cool weather that this cool spell is going to drastically slow that cotton down. And it's an added stress so that's when things like season disease come into play. All these other things nematodes can start working on it quite well at that point. The main thing we can do is one avoid any other practice that might further injure the cotton or delay maturity. We want to be extremely timely with our sprays or whatever action we need to take for Thrips so a lot of seed treatments expire over a certain amount of time. Same thing for in-furrow treatment. So we want to make sure uh as that first true leaf is protruding through the cotyledons. You need to be out there looking for damage and then take action very very quickly if uh action is needed. All right I want to come back to replanting. One question so if someone if someone needs to replant they go out there and there's skips and they feel okay this needs to be replanted are we recommending to just start over and replant the whole field. Or try and just try to get in there and drop the planter down in those spots and just replant spots which could cause a little bit of differentiation in maturity or or management down the road. All right so a couple of different issues going on in that scenario if this if it's just a certain area of the field that might need to be replanted and by all means we recommend only replanting that area in just this spot. In some cases stands will be so poor you have to replant the entire field. When the majority of the field comes into play, we need to think about things like herbicides and Dr Charlie Cahoon has done some really good work looking at herbicide interactions and replanting things of that nature and he can answer those questions quite effectively. But if it's a spot replant you know typically what most growers need to understand is the variation in our fields in North Carolina just from the variation in soils or what have you. If we have one maybe two weeks difference in maturity in the same field assuming cotton is planted and emerges at the exact same time so that much variation in the field is not abnormal and so replanting cotton especially if it's within two weeks of the original planting for example it doesn't really bother me in terms of maturity and how to manage that problem. Now there have been scenarios where you have extremely early planted cotton mixed with extremely late planted cotton what we say there is try to be a little lax on your PGR’s at least initially let that cotton grow and set some fruity notes and things of that nature. Let the later planted cotton catch up so to speak before we start hammering it with the PGR. But that'll come later in the year weather would dictate a lot of that. Even in our planting date study sometimes you'll see plant dates kind of move together or migrate together depending on the weather throughout the summer so at the end of the year there may not be that much difference in terms of overall maturity. So it's less of a concern in most years than most people make it out to be uh just due to the variation that we have in fields anyway. All right is there anything else you think we need to cover or we want you wanted to talk about that we haven't gotten to.
I would just say you know everybody's kind of behind and in a hurry now trying to get this crop planted. Let's not neglect to evaluate stands if cotton has already been planted and make a timely decision on replanting if needed for stands that have already been established. Like I said earlier, we just need to be incredibly timely on our risk management and start watching that Thrips. The focus right now is going to be planting the rest of this crop, naturally so, but those are a couple things that we don't need to just forget about until we're done. there may be some fields next week that need to be sprayed for thrips and if so we need to direct our attention to that.
and thank you again Dr Collins for your time today on our podcast and Dr Collins mentioned the NCSU Cotton Planting Calculator. If you just google “NCSU cotton planting calculator “it'll be the first thing that comes up. That's a great resource that those fellows have created to help you make better decisions on planting and when to plant and maybe when to hold off. Please share this podcast with anyone you know who grows cotton. If you have any questions about adequate stands and replanting decisions reach out to your local cooperative extension agent and as always thanks for listening to Crop Sense because if it's not making money it's not making Cents.