Growing Cotton in the High Plains of Texas
Cotton is used every day by everyone. The use of cotton ranges from fabrics to oil, to explosives. Cotton is considered one of the most important fiber crops grown in the world and is the number one cash crop grown in Texas. 76 percent of cotton grown in Texas comes from the area within 100 miles of Lubbock. The climate and temperature for growing cotton in the Lubbock area is key to a successful cotton crop.
Cotton is considered the perennial crop that is grown as an annual. History shows that cotton was mostly grown in tropical or subtropical areas and that has changed over time with the introduction of biotech cotton. Cotton is also classified as an indeterminist, which allows the plants to enter both vegetative and reproductive growth at the same time. This allows the plant to endure more stress and still be able to produce a successful crop.
Cotton, just as all crops, growth is measured through different developmental stages. The first developmental stages cotton enters into is the germination stage. In order for seeds to germinate and emerge in the least amount of days possible, it is important to have proper soil temperature. Adequate soil temperature should be at least 64 degrees, 6 inches down, but a higher temperature is recommended. If soil temperatures are too low when the cotton seed is planted, it can take up to 100 hours for the seed to germinate. The more optimal soil temperature an average is at least 65 degree Fahrenheit for at least ten days. A proper planting temperature is very important for cotton germination. In all cotton seeds, the seedling encounters multiple stress factors. Seedling vigor can help combat some of the factors, and one way for producers to determine seedling vigor is the Cool- Warm Vigor Index. Temperature is a factor in all aspects of growing cotton and has a large effect on the overall yield of the crop and how many days are taken to grow the crop. The next growth the cotton seedling establishes is the growth of the roots. To have a successful plant it must have a strong stand. The cotton seed should, under optimal conditions, begin to produce a radical within 3 days, and that radial will grow into the soil 10 inches or more within five to seven days, or by the time the first leaves appear, and will continue to grow up to two inches per day in the vegetative stage of the plants life.
The next stage cotton enters is the vegetative state. Under optimal conditions, the cotyledons are one to two inches above the soil surface and are on opposite sides of the main stem. After the first leaves appear, the stem consists of nodes that are determined by any stresses the plant may have, especially water. The plant should produce a new internode every two and a half to three days. If the internodes are short, that can indicate a stress factor. The nodes then produce stems and branches, some being vegetative branches, or monopodial, and some being sympodial, or fruiting branches. Vegetative growth early in the cotton plants life can indicate a good start in the growing process of the plant, but cotton can also withstand loss of leaves until the third true leaf stage. According to Texas A&M Agrilife Extension, “Factors that inhibit early leaf development include: cold temperatures, wind or hail damage, and foliage feeding insects. Root damaging organisms can also stunt early leaf development.” These factors including heat, determine the crops overall performance, even though they are impacting the beginning stages of the plant.
The final reproductive stage cotton enters into is the fruiting or producing squares stage. In this stage, temperature plays a big role in when the plant will begin to fruit. Early fruiting in cotton is desirable and allows producers to make management decisions regarding the yield of the cotton. The first square on fruiting branches with appear anywhere between thirty-five to forty-seven days. The squares on the fruiting branches will then progress through the fruiting stages. First, the square is one-third square or a match head, then will be half grown, and lastly, it will candle. Heat also plays a large role in the square developing on the bloom. The limited heat can cause this process to take much longer than if proper heat units are applied to the cotton, as well as other stresses such as cool temperatures late in the season, plant crowding, insects and dieses.
There are many factors that influence cotton and overall yield of the crop. Heat is a very important factor to growing a successful cotton crop. As shown in the above figure provided by Tennessee Extension, the heat units that need to be available to the cotton plant during all stages of growth and development of the cotton plant. Heat Units or DD60’s are an estimation that producers and researchers use to describe the amount of heat accumulated by the plant. Heat units can be calculated by anyone using the formula below.
This formula above is one formula that can be used by producers to calculate heat units. The formula is calculated by averaging the highest temperature for the day and the lowest temperature for the days and subtracting it by sixty. The reason the average daily temperature is subtracted from sixty, is because sixty is considered to be the lowest temperature that growth in the cotton plant will take place. Over time, the heat units per days are added up to show to heat units the cotton has received since planting date. This will allow producers to make management decisions based on the heat units the plant has received over its life. Using the table provided above, producers are able to mark milestones that the cotton should be reaching according to averages for cotton.
Heat is the largest limiting factor for cotton growth. From soil temperature through all stages of growth, cotton needs heat. In the high plains of Texas, it can be difficult for cotton to receive enough heat units for optimal growth, with high yielding crops. Studies have shown that the Texas high plains do receive enough heat units to grow cotton. Texas A&M University states that “…it is best to plant according to soil temperature not the calendar. If planted too early, a crop may suffer stand loss and cold temperature stress, which reduce yield potential.” In a study done in the Journal of Cotton Science, over a 30-year period, the 131 counties in the Texas High Plains, Oklahoma, and Kansas areas received over 1000 heat units, which is feasible to grow cotton but is not optimal for high producing plants.
In the charts shown below, it shows the heat units accumulated over the growing season for cotton in the Amarillo area. This chart shows a comparison of heat units accumulated over a ten-year period, compared to the 2016 growing season, and the 2017 growing season.
This formula above is one formula that can be used by producers to calculate heat units. The formula is calculated by averaging the highest temperature for the day and the lowest temperature for the days and subtracting it by sixty. The reason the average daily temperature is subtracted from sixty, is because sixty is considered to be the lowest temperature that growth in the cotton plant will take place. Over time, the heat units per days are added up to show to heat units the cotton has received since planting date. This will allow producers to make management decisions based on the heat units the plant has received over its life. Using the table provided above, producers are able to mark milestones that the cotton should be reaching according to averages for cotton.
Heat is the largest limiting factor for cotton growth. From soil temperature through all stages of growth, cotton needs heat. In the high plains of Texas, it can be difficult for cotton to receive enough heat units for optimal growth, with high yielding crops. Studies have shown that the Texas high plains do receive enough heat units to grow cotton. Texas A&M University states that “…it is best to plant according to soil temperature not the calendar. If planted too early, a crop may suffer stand loss and cold temperature stress, which reduce yield potential.” In a study done in the Journal of Cotton Science, over a 30-year period, the 131 counties in the Texas High Plains, Oklahoma, and Kansas areas received over 1000 heat units, which is feasible to grow cotton but is not optimal for high producing plants.
In the charts shown below, it shows the heat units accumulated over the growing season for cotton in the Amarillo area. This chart shows a comparison of heat units accumulated over a ten-year period, compared to the 2016 growing season, and the 2017 growing season.
At this beginning of this season, Texas A&M AgriLife Extension predicted a high yielding year for cotton in the Texas High Plains. At the beginning of this growing season, that temperature showed favorable amounts of heat units being accumulated in the cotton plant. That was soon followed by cloudy and cool temperatures, during the period of time when the boll was still maturing, causing a drop in the overall potential yield that is predicted for the area.
In researching this topic, the overwhelming research showed that heat units in growing cotton is a critical part of growing a successful cotton crop. In the high plains of Texas, this can be a limiting factor, especially towards the end of the growing season, as shown in the graphs above. To combat this problem, research through a variety of testing different genetics, could lead to a more successful cotton crop.
To research the limiting factor of heat units in cotton a plot test would be the most successful way to understand and see the differences, not only for research purposes but for producer education as well. In this plot test, it would be imperative to plant 3 different varieties of cotton all at the same depth, row spacing, and use all the same chemical applications to achieve a test only to test the factor of heat unit’s relative to overall yield of the crop. In this test, there would be 3 rows of each variety that would be replicated 3 times, equaling 9 rows per variety. The cotton would be planted at a 38inch row spacing, in a 500ft row, all seeds planted at one inch depth. The different varieties that would be planted would be FM 1320GL Variety, this is a variety that FiberMax released that is an early maturing, semi-high yielding variety. The next variety would be NG 3306 B2RF, which is a variety that NexGen released that is a Early- Medium maturing variety that is high yielding. Lastly the PhytoGen variety PHY 222 WRF would be planted, this a very early maturing crop that would offer a semi high yielding crop.
With this plot test detailed above, the goal would be to research an early maturing high yielding crop that producers could utilize in their operations. Within this plot test the overall factor that would be tested would be overall yield when harvest. Another factor that would be tested for would be the days from planting to germination, from germination to nodes developing on the main stem, from nodes developing to first squares produced, first squares produced to first flower and flower to open boll, and overall days from planting to harvest. Showing the days for each developmental stage would allow for producers to make management decisions based on days for each developmental stage. Other factors to be tested would be fiber length, and other value added factors when marketing cotton after harvest.
The research done by Texas A&M AgriLife Extension shows early maturing crops to produce better in the Texas High Plains. This additional research would identify specific varieties that would suitable for growth in the Texas High Plains and factors associated with those varieties that would allow producers in the Texas High Plains to choose varieties and management decisions that would improve their overall yield of cotton crops.
Cotton is a useful and necessary cash crop to be grown in the United States, and across the world. With the limiting factor of heat there is limited places to grow successful cotton crops across the globe. Research testing different varieties and genetics would lead to more cotton being produced around the world and specifically in the Texas High Plains. Allowing producers to have access to this information such as different variety’s and yield associated with those varieties could highly impact the cotton industry as a whole.
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