- Excessive rainfall during the first half of July is affecting some Alabama cotton fields.
- Cloudy weather and water-logged soils can have an impact on growth habits.
- Root growth is not highly tolerant to saturated soils.
The USDA-NASS reported on July 8 that 82 percent of Alabama’s cotton crop was squaring. This is similar to the 2012 crop but ahead of the five-year average of 64 percent.
In addition, 22 percent of the crop is in fair condition and 77 percent in good to excellent condition. The rainfall during the first part of July stopped most of the fieldwork by land applicators. At the same time, cotton plants are responding accordingly to saturated soils.
So what effect on cotton will the excess rain have over the next few weeks?
With the excessive rainfall during the first half of July, there are a lot of fields that have low areas where plants are suffering. There is so much that is happening within and around the plant that it is important to tie it all together.
Just to list a few things:
• Cloudy weather: Besides being a favorable environment for tarnished plant bugs, it has been shown that extended periods of cloudy weather can result in decreased photosynthetic rates in the plant. Since cotton is a perennial plant, it is genetically “wired” to shed fruit during times of stress and resume fruiting later in its life cycle. The bottom-line is that producers may see dead, brown squares shedding from the plant as a result of the slowdown in food production. The damage looks very similar to squares dying from plant bug damage. The play also may shed one- to three-day-old bolls just after it flowers. The plants should recover quickly from this with sunshine and drier conditions.
• Water-loggd soils: Plants require adequate oxygen in the soil in order for “respiration” to occur. Respiration is the process through which the plant converts the products of photosynthesis into useable energy. When oxygen is not available in the root zone, the plant cannot maintain critical processes. Often, the plant will cease to grow for a time, chlorophyll cannot be maintained (causing the plant to turn from green to yellow and red), and the plant may actually wilt. Plants can regain their green coloration and photosynthesis will start again if flooded conditions are alleviated within a few days.
• Root growth: Cotton is not known to be highly tolerant to long-term saturated soil conditions. If saturated conditions exist for too long, the root system will begin to deteriorate or will simply not grow to the optimum depth. If this occurs, producers may notice that the plants in the lower areas of the field where water tends to pond may become drought stressed more quickly than in other well-drained areas. Again, being a perennial plant, cotton likely will begin to grow more roots as the season continues with sunshine and drier soil conditions, but the overall system likely will be limited.