PLANTER SETUP. Research has shown that uniform populations of 30,000 to 60,000 plants per acre can produce high yields. Economically, a final plant stand between 36,000 and 44,000 will provide the highest return on your cottonseed investment. Excessive plant populations will cause higher fruiting on the plants, shorter limbs, smaller bolls and fewer bolls per plant. A stand of three to five plants per foot-of-row will require four to six seeds per foot-of-row under normal conditions. The following table will help determine the row spacing required to obtain a desired plant population.
Row Spacing (inches)
Plants per foot
Plants Per Acre
After carefully calibrating your planter to plant the desired number of seed, check the depth seed are placed. Set the planter to place seed 0.5 to 1 inches deep. The depth will have to be rechecked when soil conditions change (soil moisture, soil temperature, soil texture, crusting potential) and switching between conventional tillage and no-tillage practices. When planting 0.5 to 0.75 inches deep, take care to ensure the seed are covered to prevent seed from drying out or injury from herbicides. As the soil warms and moisture is lost, the seed may be planted 1 to 1.5 inches deep to allow planting in moist soil. Never plant cotton seed deeper than 1.5 inches.
PLANTING DATE. Let the calendar tell you when to get your planter ready, but let soil temperature tell you when to start planting. To help make planting decisions, a cotton planting forecast can be calculated. A planting forecast will consider the predicted temperatures, DD60 accumulation, rainfall, and potential for drying winds. Seed germination and successful emergence is favored by adequate soil oxygen, moisture, and warm soil temperatures (above 65°F).
Soil temperature should be 65 degrees or higher for good rate of emergence of healthy vigorous plants. Check soil temperature at a 2-3 inch depth at 8:00 - 10:00 a.m. for three to five days to make sure the seedbed has reached 65 degrees and warm dry weather is predicted for the next five to seven days.The table below provides guidelines for the likelhood of establishing a stand of cotton based on the predicted accumulation of DD60s for the five day period after planting.
Less than 10
Greater than 50
An easy way to determine your five day prediction is to visit the Cotton Planting Conditions Calculator from the North Carolina Climate Office (http://climate.ncsu.edu/cotton_planting). After navigating to the site, use the map to find your farm, click to mark the location and then click the submit button below the map. This will produce a table that gives you a five day forecast for today and the next two days based on the guidelines above.
Seedling vigor is very important since the most rapidly emerging seeds in a stand produce the greatest yield. Seedling survival is greatest when seeds emerge five days after planting (87% survival), compared to 12 days after planting (30% survival). Additionally, the relative yield of seedling emerging on the fifth day after planting are near 100% while those emerging on the 12th day after planting only produce about 29% of the relative yield.
The first 24-36 after planting is most critical for strong seedling emergence. As depicted in the figure below, seedlings are most susceptible to chilling injury during this time period. If there is a high chance of rain within 36-48 hours of planting, it is better to delay planting than to risk having to make a replant decision 10-14 days later.
Planting too early, even into conditions that promote seedling emergence, also can be detrimental. The figure below shows the impact of cool temperatures on emerging cotton seed. For each day minimum temperatures are below 60°F, you will see 61 lbs/day DECREASE in yield (Camp et al. 1997).
In this same research from South Carolina the amount of heat units accumulated during the first 50 days after planting impact overall yield potential for the crop. The difference of 120 heat units during this time period caused a yield difference of 914 lbs/ac or 7.6 lbs of lint per additional heat unit.
With commodity prices low and profit margins thin, each planting decison needs to be executed timely and with sucess in mind. Plant high quality seed into conditions that promote rapid early growth and development to achieve the highest yields possible. Seed has its highest yield potential when it is still in the bag. Every decision we make about planting and crop management impacts the return on our seed investment.