AG OUTLOOKLA NIÑA WINTER 2010Clyde Fraisse

Agricultural and Biological Engineering

University of Florida

November 18, 2010

Albany, GA

Potential Impacts on AgricultureLa Niña 2010-2011

• Winter vegetables• Winter pasture• Temperate fruits• Forestry• Row crops

Major Freezes in Florida CitrusFreeze Event ENSO Phase

December 1894 Neutral

February 1899 Neutral

December 1934 Neutral

January 1940 Neutral

December 1962 Neutral

January 1977 El Niño

January 1981 Neutral

January 1982 Neutral

December 1983 Neutral

January 1985 Neutral

December 1989 Neutral

January 1997 Neutral

Adapted from: John Attaway, “A History of Florida Citrus Freezes

Winter Vegetables

• Tomato and green peppers generally yield more during La Niña years than during Neutral or El Niño years.

• Dry weather associated with La Niña generally decreases fungal and bacterial diseases. Increased solar radiation is also a factor. Source: Hansen, J.W., Hodges, A.W., Jones,

J.W., 1998. ENSO influences on agriculture in the southeastern US. J. Climate 11 (3), 404–411.

Winter Pasture• Success of winter pastures

depends on rainfall. This is especially true when overseeding.

• In central and south peninsular Florida, overseeding of cool-season annuals into an established grass sod often fails due to insufficient soil moisture

Winter Pasture• Based on the current dry conditions across parts of the

Southeast and the probability of a dry winter, the following considerations should be made in regard to winter pasture:• Soil moisture at planting will be an important factor for success,

postpone planting If the soil is dry;• Prioritize planting in prepared seedbeds where chances of success

are higher, avoid overseeding;• Plant in best fields that typically hold moisture in the winter;• Don’t invest only in winter forage, save some dollars for feed

purchase;• Be prepared to reduce stocking rates and number of grazing days

with the expected reduced rainfall.

Temperate Fruits• Seasonal climate

variability impacts deciduous fruit production mainly because of a decrease in the satisfaction of dormancy that occurs by the accumulation of chilling hours (temperature at or below 45°F)

Chill Accumulation Variability• Chill hours variability in:

• Alachua• Hendry• Hernando• Marion• Pasco• Polk• Sumter

• Chill Hours (32°F ≤ T < 45°F)• From Oct 1st to Feb 28th • Entire period of records 1948-2007• Different ENSO phases:

• Neutral• El Niño• La Niña

C. W. Fraisse, Agricultural & Biological Engineering

Chill Accumulation Averages Entire Period of Records

C. W. Fraisse, Agricultural & Biological Engineering

Alachua Marion Sumter Hernando Pasco Polk Hendry0

100

200

300

400

500

600

522

354 348

262232

204174

Average Chill AccumulationChill Hours (32F ≤ T < 45F)

El Niño - Southern OscillationMarion County 1948-2007

El Niño La Niña Neutral All Years

Average 405 284 362 354

Minimum 222 146 110 110

Maximum 598 500 593 598

Temperate Fruits - Diseases• The dry weather during La

Niña years is usually not conducive to fungal diseases such as Anthracnose and Botrytis fruit rots.

• Regular applications of fungicides may not be needed as often to suppress these diseases.

Seasonal Forecast of Disease PressurePlant City, Florida – 1892 to 2009

C. W. Fraisse, Agricultural & Biological Engineering

Forestry• Managers could consider:

• Re-scheduling planting of drought vulnerable seedlings

• Reinforce existing control efforts of southern pine beetle

• Delay the harvest of pine straw to retain soil moisture

• La Niña also brings the potential for a very active wildfire season.

Row Crops• Warmer and/or drier conditions

may help certain pests and diseases:• Warm, dry winter may increase flower

thrips abundance• Warm conditions may also help

soybean rust over-winter on kudzu in South Georgia and throughout the Panhandle of Florida

If conditions are dry during the spring it may be best to kill cover crops earlier in order to preserve more moisture in the soil

Drought Monitoring and Forecasting

Agricultural Reference Index for DroughtNOAA-Sector Applications Research Program

Survey

& Prototype

Workshops in FL & GA

Refinement of the tool

Release of final version

on AgroClimate

Training Workshops

AgroClimate Cycle

Objective: Develop a decision support system on AgroClimate specifically designed to help forage producers cope and adapt to drought conditions in the southeastern USA

Drought Workshops w/ Forage ProducersFanning Springs, FL October 14, 2010

Tifton, GA October 15, 2010

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