Agfax Buzz:
    July 18, 2014
    cotton-sprayer-06302014-featured

    Florida Cotton: Fertilizing Late Planted Crop

    AgFax.Com - Your Online Ag News Source

    By Josh Thompson, Florida Extension Agent, Jackson County

    Fertilizing cotton is always a major factor that affects yield in the Panhandle. Last year we saw plenty of cotton fields run out of nitrogen (N) during the summer with the relentless rains. We also saw growers trying to apply N, through irrigation or ground, when it was too late to do any good. So what are some fertilization guidelines that years of research provide us with?

    Phosphorous and Potassium

    Phosphorous (P) and potassium (K) fertilizers should go out prior to or at planting and should be based on soil test recommendations. These nutrients are essential for good early season growth and can be applied in a complete fertilizer blend (i.e. 5-15-30). It is not necessary to apply more than 20-30% of the total N at planting because the main N demand does not begin until cotton starts blooming.

    On sandier fields it may be a good idea to split K applications, applying half at planting and half with N sidedress. This is because K can be leached in sandier fields. K deficiency has been shown to be a cause of some leaf spot diseases that occur later in the season.

    Nitrogen and Sulfur

    Nitrogen obviously has a major impact on yield. Research shows that side-dress N should be applied between squaring and first bloom.

    Total N for the season should range between 60 – 120 lbs/acre. The amount needed will vary depending on soil type and yield potential. Greater yield potential will require a rate towards the upper end of the range, however, a low N rate does not necessarily mean low yields. With good rainfall, even some non-irrigated farms can make 2 bale cotton with 70 lbs. of N on heavier soils. Rainfall is usually a more limiting factor than N.

    Sulfur is also an important nutrient for cotton production, especially in sandier fields. The recommended rate of sulfur is 10 lbs/acre. This can be achieved by using ammonium sulfate (21-0-0-24S), liquid “28” which is 28-0-0-5S, or “K-mag” which is 0-0-22-22S-11Mg.

    How late is too late for N?

    Unfortunately, some growers learned this the hard way in 2013. Multiple years of research from Dr. David Wright and others has shown that applying N beyond the 3rd week of bloom will not increase yield. This is true even if the field is deficient in N. When it gets late in the season, cotton naturally begins to look pale green or slightly yellow. This occurs because the plant is sending its nutrient resources into the young bolls, and does not necessarily indicate an N deficiency. According to Dr. David Wright, UF/IFAS Extension Agronomist, excess N during late bloom has actually shown decreased cotton yields in some trials.

     


    Tags: , ,

    Leave a Reply

    Name and Email Address are required fields. Your email will not be published or shared with third parties.

    Agfax Cotton News

    Doane Cotton Close: Positive Chinese Economy Boosts Prices10-21

    Dual Space Shop Offers Weather Protection, Equipment Storage – DTN10-21

    DTN Cotton Close: Snaps String of Five Lower Finishes10-21

    Texas Crop Weather: El Niño Stalled Out but Cool, Wet Winter Still Predicted10-21

    USDA to Implement APH Yield Exclusion for 2015 Spring Crops10-21

    AgFax Cotton Review: Australian Production on Rise; Mississippi Mill Faces Closure10-21

    DTN Cotton Open: Near Unchanged in Tight Ranges10-21

    DTN Fertilizer Trends: High Costs May Alter Growers’ Tactics for 201510-21

    Keith Good: Tumbling Grain Prices May Prove Costly for Taxpayers10-21

    AFB Cotton Close: Selling Accelerates10-20

    Doane Cotton Close: Weakness in Prices Carries On10-20

    Mississippi: Rains Slow Harvest, Lodge Rice, Soybeans – USDA10-20

    Tennessee: Rains Halt Field Activities – USDA10-20

    Arkansas: Rains Damage Crops, Slow Harvest – USDA10-20

    North Carolina: Corn Harvest Enters Final Stretch, Rains Delays Continue – USDA10-20

    Florida: Harvest Continues, Peanuts Reach 69% – USDA10-20

    New Mexico: Dry Soil Conditions Persist — USDA10-20

    Missouri: Corn Harvest Over Half Finished, Cotton at 30% – USDA10-20

    Texas: Harvest Chugs Ahead – USDA10-20

    Arizona: Cotton 50% Defoliated, 28% Harvested – USDA10-20

    Kansas: Row Crops Harvest Behind Average Pace — USDA10-20

    Oklahoma: Corn Harvest at 76%, Soybeans 22 — USDA10-20

    South Carolina: Peanut, Cotton Harvests Pick Up – USDA10-20

    Herbicide Resistant Weed Summit’s Slides, Webcast Available Online10-20

    Georgia: Cotton, Peanut Harvests in Full Swing – USDA10-20

    Alabama: Rains Have Harvest at a Standstill – USDA10-20

    DTN Cotton Close: Mixed as December Premium Narrows10-20

    Louisiana: Soybean Harvested Wraps Up – USDA10-20

    California: Cotton, Rice Harvests Speed Along – USDA10-20

    Virginia Cotton: This Year is Going to be Special10-20

    DTN Cotton Open: Ticks Lower as Inversion Narrows10-20

    Flint on Crops: Cover Crops Provide Many Benefits10-20

    Keith Good: Lawsuits Concerning GMO Corn Mount Against Syngenta AG10-20

    AFB Cotton Close: Dec. Moves Lower10-17

    Rose on Cotton: Dec Contract Still Under Pressure10-17

    Cleveland on Cotton: Exports Lowest in ‘My Memory’10-17

    DTN Cotton Close: Mixed As Dec. Loses Ground10-17

    Mississippi: Harsh Oct. 13 Storm Should Not Hurt Yields10-17

    Georgia: 6 Counties Declared Natural Disaster Areas10-17