By Bill Robertson, Extension Cotton Agronomist; and Amanda Free, Cotton Research Verification Program Coordinator
Cotton Update Overview
The cotton crop continues to make good progress both above and below the soil surface. It was not a problem last week to find good cotton roots 16 inches below the soil surface in a core sample on 8 inch tall cotton. Field work, particularly weed control is job one at this time. Wet weather in and around planting and the string of windy days has had most in the catch-up mode all season. Pigweeds are getting larger than most like to see, but we are doing a decent job of holding them back. Many producers this last week are working on the second round of our over-the-top products for that knockout punch. Highboys and hooded sprayers are a common sight all across the state. Many still need a few more days yet to get across the farm. Unfortunately, we are also beginning to see off-target movement of some of our herbicides.
The National Agricultural Statistics Service (NASS) Crop Progress and Condition Report for the week ending June 3 (last week) reported cotton squaring at 11% which was ahead of the five-year average of 5%. Crop progress should continue to be well ahead of the five-year average with current favorable conditions. They also reported that 86% of the cotton was in good (53%) to excellent (33%) condition with only 13% being fair, 1% poor, and none rated very poor.
The NASS acreage intentions released March 29 were at 480,000 acres, up 8 percent from the 445,000 acres planted last year. Early June numbers from the Arkansas Boll Weevil Eradication Foundation has the state near the 455,000 planted acre mark.
Mepiquat chloride applications were made on our end of April and first of May planted cotton beginning last week. Common timings to begin the use of this product is pinhead (PHS) to match head (MHS) square or the 9 to 10 node cotton. This product works as a result of the concentration in the plant which goes to reason that it is much easier to obtain and maintain the desired concentration in a plant if we start early on a smaller plant. It is difficult to even obtain the concentration needed to be effective if we start late on a large plant. Our more aggressive varieties on strong ground are receiving 16 oz/A for starters. Most report that they are going with a base of 12 oz/A and bumping it on strong fields with aggressive varieties and dropping in weaker areas. Of the very early planted cotton, very few are dropping below the 10 oz/A rate.
Traveling across the state, it was common last week to see many producers starting irrigation in soybeans. It is rare that we irrigate pre-squaring cotton in Arkansas. However, we often see many of our record yields occurring in years in which we see little water stress once cotton begins squaring. The first sign of stress we can easily measure in pre-squaring and squaring cotton is a change in the rate of node production. Node production will slow from that expected when cotton is stressed. Cotton will add a new node every 50 to 60 DD60s. Tom Barber has studied irrigation initiation in cotton. One week before flower is a critical time to avoid moisture stress in cotton. May 1 planted cotton could begin flowering 50 to 55 days after planting this year putting us about 2 weeks from flower today. Historically June 15 to 18 are a good target dates to be ready to initiate irrigation of cotton. This target may be very appropriate for this season.
In our Verification/Sustainability fields we monitor soil moisture at a 6, 12, and 18 inch depths as well as monitoring the rate at which the plants put on a new node or leaf from emergence. Our 6 inch sensors are getting dry but we have very good soil moisture levels at the 12 and 18 inch depths. Node production has appeared to slow slightly but the slope of the line for node production from the 2ndtrue leave to last week, for our fields has basically mirrored that of the Target Development Curve in COTMAN. Node production at this time is still adequate.
Ideally we need enough dry calm days to finish our over-the-top weed control programs and then catch a good rain to get us to layby and then lay our pipe. The current ten-day forecast does not indicate adequate rainfall amounts to occur to meet our needs. We need to be getting our irrigation plans in place.
2018 Cotton Research Verification / Sustainability Weekly Update
June 8, 2018
There are 12 Cotton Research Verification / Sustainability Program fields in 2018. Growth stage across fields ranges from 4 to 8 nodes. All fields have received rainfall since the previous field visit, amounts range from .02”-.58”. The fields in Desha county are squaring. All fields will be in need of a good rain soon. Fields which are squaring were graphed and compared to the Target Development Curve (TDC) in COTMAN with previous node counts to make sure cotton growth is still adequate. At this time all fields that are squaring are running parallel to the TDC. Both thrips and plant bugs have been seen in fields but numbers are well below treatment level at this time.
See linked pdf for field-specific information: Arkansas Cotton CRVSP Update June 10, 2018