This year has been such a contrast with last year. We have gone from exceptional drought to prolonged wet conditions.
When the rains began, it was welcomed by everyone. July and August rains are sometimes called million dollar rains by those in the agricultural community. Rain that this time of the year really helps the crops to grow to grow and producers can stop their irrigation. By not irrigating, they can save a lot of money on fuel costs.
While the weather has been different this season, there are potential impacts due to the weather.
The Missouri Crop Progress and Condition Report for the week ending August 11, shows that we are generally behind in crop development and temperatures.
For soil moisture, we are showing 55 percent of our soils have surplus moisture. In other words, it's too wet to get into the fields. Insecticides and growth regulators are being applied by air. Growth regulators are very important to keep the vegetative growth under control. Even some non-irrigated fields are requiring growth regulators this year.
For the last month, Dunklin County has received over 6 inches of rain. We have seen rain off and on for a little over two weeks.
With this rain, corn producers will not need to irrigate for the remainder of the season. However, the bad news is that the corn is not drying down. We could use a couple of weeks of hot, dry weather to dry down the crop.
Cotton setting bolls was 72 percent complete, 1 day behind last year and 12 days behind normal. We should have a few open bolls in the earliest planted cotton, but I have not seen any reported this year. Cotton condition was 8 percent poor, 35 percent fair, 55 percent good, and 2 percent excellent.
We may have reached a time of the year that is referred to as the last effective bloom date. This date normally occurs between the 12th through the 15th of August. This is the last date on which a white bloom on the plant can mature into a harvestable boll.
This is the average date but the time may be longer or shorter depending on the temperatures for remainder of season. Much of our cotton was planted after the optimum planting date and an early fall could reduce the number of top bolls being harvested.
Looking at the normal distribution of squares, blooms, and bolls, the first four weeks of bloom are critical. During the first week of bloom, 94.1 percent of the blooms will develop into bolls. This is 16.8 percent of the total bolls for the season.
During the second week, only 77.7 percent of the blooms will set, but with the higher blooming rate, this will be about 40.8 percent of the total bolls. During the third week of bloom, only 43.1 percent will set but this is 27.2 percent of the total bolls.
During the fourth week, only 20.7 percent of the blooms will develop into bolls, and this will be about 10.9 percent of the total bolls.
So during the first four weeks, almost 96 percent of the bolls are being set.
The bolls that are being set closer to the stem are called first position bolls and they make up a larger percentage of bolls that set. This is due to the fact that they receive more plant nutrients than bolls that are set much farther on the branches.
The best way to shut the plant down prior to harvest is for the plant to have a heavy boll load. Protecting the bolls from insect loss will allow the plant to stay on track and not having to produce fruit late in the season.
I have tagged blooms near the 15th of August and very few of them will set. Boll set is not very reliable later in the season.
We have a unique situation with the very wet conditions. I usually see this after rainfall, but sometimes rain will cause the plant to start dropping squares and small bolls.
This year, it looks bad to see this fruit in the middles. However, this occurs every year to some extent and it might be worse due to the cloudy conditions.
It has been said that if a cotton plant could set all of the blooms each year, then the yield could be about 8 bales per acre. This will never happen but the cotton plant producers far more blooms than it could set.
The growth of the cotton plant is very predictable under favorable moisture and temperature conditions. Growth follows a well-defined and consistent pattern expressed in days.
Another useful and more precise way to assess crop development relies on using daily temperatures during the season to monitor progress. The heat unit concept utilizes accumulated hours above a critical temperature rather than calendar days in describing growth and development.
The growing degree days (DD) concept is based on a developmental threshold above which the crop grows. Below that temperature is where little or no development occurs. For cotton, the threshold temperature is 60F; therefore, the degree days are referred to as DD60s. The basic formula for calculating heat units involves averaging the maximum and minimum temperatures for each day and subtracting the threshold temperature.
From May 1 through August 1, we have had 1435 heat units. This is less than the 1624 for the same period last year and 1732 in 2011. However, the record yield occurred in 2008 with 1,106 pounds per acre and we only had 1114.
With the season that we have had this year, it will be interesting to see how our cotton yield turns out.
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