Most of our cotton was planted from May 11th to May 25th this year which represents 14 calendar days, but only 7 degree days. This is going to bring a little bit of a different spin on our cotton management, and I think it will make decision making more straightforward because cotton will be very close to the same age. The blooming dates will be bunched up closer together. Just for figuring purposes, and since we plan some of our management based on weeks until bloom initiation or weeks after bloom, I would predict our first bloom won’t appear until July 15th. Then over the next week or so, most of it will start blooming. That also means that we will not be insect safe until the end of August on the first planted cotton until perhaps the first week of September on the late cotton. That correlates to the 5th to the 6th week of bloom which is the amount of blooming time we need to lock in 2 to 3 bales per acre with timely rain. Weed control and fertilizer on light land are going to be our upcoming top priorities. We still have several weeks to finish final nitrogen applications, but riding around this week, I can already see that white land showing smaller cotton and some typical paleness from the light land syndrome of pH, potassium, nitrogen and sulfur challenges. It's not always a lot of acres, but that 5 acres in a 40 acre field draws your attention. I’ll send an email to address a few detailed fertility and weed control questions.
Periods of rainfall for much of this week will reduce our opportunity for field work. Most farmers are on schedule with chores, although being caught up may not be attainable during periods of rapid plant development like June. June actually is one of our busiest months as we have all of our crops each having their own needs. Peanuts and cotton are our biggest money makers, but wheat harvest will have her way and not be treated second during June. Hopefully the early beans are planted and corn has been topdressed so that we will be able to get back on our money makers as the ground allows. Most cotton fields are finished with thrips management and the first round of weed control, but with this rain will come new flushes of weeds and also some dilution of our most water soluble herbicides like Reflex. We might even be able to slip in between showers with a residual herbicide like Dual/Warrant/Outlook on fields that haven’t gotten sloppy. Outside of that, it will be a good week to walk some fields and put a plan together.
After Thursday’s rainfall, the next and perhaps more voluminous rain event is expected for a good part of next week. Leaching concerns are not too high at this point since our final nitrogen applications have not been made. There always seems to be some concern for light sandy soils with the low CEC for holding nutrients as well as maintaining pH. These fields do not hold much water so they are very droughty, and at the same time when large amounts of water come, they get washed out. When we apply all the potassium and sulfur at planting, any leaching rains create concerns. This common situation has us implementing strategies that include potassium applications after crop emergence or in topdress. This current weather event has me thinking we need to think through sulfur and potassium with our layby nitrogen trip on these super light fields. The majority of our land has more loam or organic matter and does not have potassium leaching issues. These more productive fields will not need potash in the topdress as long as the soil test was already followed.
Rainfall moving in Thursday evening is expected to deliver between 1 to 2 inches through the region. Some communities will be in the path of some heavier thunder storms that could bring rainfall totals closer to 3 inches locally. Through the weekend into early next week, we could see several rain events delivering a quarter inch or so each day. Needless to say, field work in agriculture is going to come to a halt for several days. It leads me towards anticipating where our cotton crop might be once this system clears out and also what we might need to plan for. One of the observations I have already made is that the cotton that was planted in May is all at about the same stage ranging from 2 to 4 true leaves. Then June 1 planted cotton is only about a week or so behind being at the cotyledon to one true leaf stage. A week from now, all cotton will add about 2 true leaves.
When we can go again, we are going to continue facing weed control as the top priority followed by fertilizer applications. By the calendar, we normally have more done by this point, but we won’t be behind. I would say the earliest cotton will not bloom until July 15th and it will be closer to the 20th of July before we see cotton blooms easily. So we have time.
With the potential loss of dicamba, we might have to rely on Liberty a little harder and this product needs to be applied to small weeds. The weed control issues will have to take priority over fertilizer in order to catch the weeds before they get too big.
For Nitrogen. I usually recommend targeting the timing of single sidedress applications to occur between the 6 and 9 leaf stage for a happy medium. That also correlates to being able to find a few small squares and a canopy around 12 inches tall with a range of 8 to 20 inches. If you have low leaching concerns and high nitrogen levels at planting, then the final sidedress could be delayed a little longer. When splitting fertilizer applications we focus on an early trip on seedling cotton prior to the 5th true leaf and a second application around 3 weeks later. I expect after this rainfall, sandy land cotton is going to start looking hungry pretty quickly.
Hot, Humid, Moist - Herbicides will work Well
This week will offer more opportunity for field work as the chances for rainfall are lower and less frequent. Nevertheless we will have to pay attention to pop-up afternoon thunderstorms which add the risk of wash off. Roundup is safe after 30 minutes, but Liberty, Enlist and the Dicamba products need 4 hours for good results. Leaf Scorch with Dual, Warrant, or Outlook is also back on the radar. The environmental factors which include humidity, temperature, and soil moisture are all going to be high through Wednesday which creates a tender leaf, particularly in the morning. After the sun hits that cotton for several hours, it gets tougher and we do not see as much scorch as the day progresses. It is also more scorch when adding two other herbicides with the Dual/Outlook/Warrant compared to just one, and by themselves, scorch is low. Leaf scorch up to 25% is cosmetic on this fast growing cotton and in a couple weeks, it will have 4 or 5 new leaves out to cover up the burn.
The cotton during the first week of planting is all at about the 7 leaf stage and the 8th leaf is clearly visible in the bud. This has brought us to the window to apply the layby nitrogen, and none too soon. We have had various amounts of rain over the last two weeks with some areas approaching 5 inches while some spots have only had around 2. The average has definitely been over 3. Our lightest land that has not had any fertilizer since before planting is showing nitrogen deficiency symptoms with red cotyledons at the bottom. Some saturated land also shows these symptoms because the root system is hurt and cannot access the nutrients close by. For both of these situations, a little bit of Ammonium sulfate broadcast will be the best and fastest cure. It only takes 100 to 150 pounds. If you are planning on dribbling nitrogen in the middles, this light land or cotton with damaged roots will not pick up that dribble quick enough and I still recommend some dry material broadcast. If you make this as an additional trip that you were not planning to do, be sure to account for this nitrogen as we do not need to apply extra nitrogen on this later than average crop. We have not really had leaching, and I believe the nitrogen we have applied up til now is still there just too deep for small plants to pick it up, but it will find it later.
Applying a half pound of boron at sidedress will eliminate the need for foliar applications, or you could apply a quarter pound to the soil and the remainder in one foliar trip. Basically the recommendation is for a half pound “in season” which can be made to the soil or foliar although the foliar trip can only have a quarter pound at one time.
Sulfur is readily available if you have organic matter in soil or clay within 12 inches of the surface. Our main concerns are on deep light soils. Similar to nitrogen, sulfur can leach, however, only about 20 pounds is needed at sidedress time. If you have 35 pounds of sulfur on light soil or 20 already on loamier soil, you are probably in good shape; otherwise use some sulfur in your side dress to meet these goals.
Potassium should not have leached. If you had planned on adding potassium with your sidedress application to meet the soil sample recommendation, just continue as planned. I like splitting potassium on the white sand that typically has the light land syndrome and this year it is showing up just like almost every year. You cannot put out enough at planting to last on these spots. Splitting is not necessary on our typical sandy loam, productive soils where leaching only comes from monsoons like we had May of 2016.
The Layby rig or Injection rig is considered to be the best way to apply sidedress nitrogen but is also slower. One big advantage is that it stabilizes nitrogen against environmental loss so you do not need to add stabilizing products that reduce leaching or volatilization. This in part likely explains its efficiency rating of 120%. In other words there is a 20% gain over broadcasting or dribbling. We don’t recommend cutting nitrogen when using it although you could. Rather there is some evidence that it puts that efficiency towards added yield potential if the rain pattern favors higher yield. Another advantage is that it puts nitrogen closer to the plant than dribbling and it does not need rain to activate it. Being closer to the plant can help some of these current symptoms we are seeing on white sand and from damaged roots, although broadcast is still a better cure for this problem.
Using urea in blends or by itself is has some pluses and minuses. Ammonium sulfate is stable and provides a lot of sulfur, but creates so much acidity plus is the most expensive way to add nitrogen. Some are looking for other options, and for dry broadcast, urea meets some goals. Urea is fairly unstable and melts from humidity plus if you put it on top of wet soil, it will turn to gas and you can lose a lot of it. For this reason, we recommend coating it with a urease inhibitor product. 1.5 pounds of NBPT/ton of urea provides the best happy medium between cost and effectiveness. If you have already met the sulfur requirement then using pure urea is simple and economical. If you blend it with some Ammonium sulfate to meet the sulfur requirement, treat the urea first before making the blend, because only the urea needs treating. Apply it the day it was blended as the AMS breaks down the coating.
ESN is urea with a physical coating for slow release. It may require as long as 6 weeks to completely release so it needs to be applied early.