Robert Hochmuth Multi County Extension Agent

Suwannee Valley Agricultural Extension Center, Live Oak

Our Main Objective

Suwannee Valley Extension Demonstrations for Nutrient &

Irrigation Management

Objective:

• To improve efficiency of nutrient and water delivery by vegetable growers in the Suwannee Valley region using plastic mulch and drip irrigation.

Methods:

• On-Center Research Projects

• Field Days

• Drip Irrigation Schools

• On-Farm Demonstrations

• On-Farm Field Days

• Farmer commodity meetings

Using Blue Dye to Visualize Water and Nutrient Movement

T0 –1h 1h 8in 2h 12in

4h 15in 8h 26in

Ro-Drip

0

5

10

15

20

25

24 36 48 60 72 96 115 139 173 192

Dep

th (i

n.)

Water Applied (gals/100ft.)

Dye Tests using Robert's Ro-Drip Tape @ 24gal/100ft at the North Florida Research and Education Center-Suwannee Valley

3/3/2002

5/9/2002

12/3/2002

3/25/2003

Combined Avg.

Linear (Combined Avg.)

Regression line: Depth = 0.1 Vol + 4

On-Farm Blue Dye Demonstrations

On-Farm Mobile Blue Dye Demo Trailer

• Early Season extended irrigation events pose a great risk for leaching entire fertilizer application under plastic mulched beds

Field Day Demonstrations at Center and On-farm

Drip Irrigation School

• Early Season (first 4 wks) – greatest risk of leaching

– irrigation was generally reduced by 50%

• Mid Season – Irrigation sensors “caught” rapid increase in water demand (late April – early

May)

• Late Season – Very difficult to over irrigate

– Lowest risk of leaching

• Single irrigation events in sandy soils in SV should be no longer than 1½ hours

• “Blue Dye Don’t Lie”

• Videos available at http://vfd.ifas.ufl.edu

Blue Dye Applications With Overhead Systems

One inch Irrigation = 12 inches Deep

Two inch Irrigation = 26 inches Deep

Monitoring Plant Nutrient Levels with Petiole Sap Testing Procedures

• N the “throttle” • K consistent, rarely deficient

• Sap testing used for several years

• Nitrogen and Potassium

• Adjust injections

based on weekly

sap testing results

600

800

1000

1200

1400

1600

PP

M N

itro

gen

Sap test Nitrogen

Nitrogen Upper Limit

Actual Nitrogen

Nitrogen Lower Limit

Samples collected every 7 days.

• Connection of Specific Demonstrations – Soil Moisture Monitoring Sensors – Sap Testing – Blue Dye

• Combination of Methods – SVAEC Trials & Field Days – Drip Irrigation Schools – On-Farm Demonstrations – Virtual Field Day Videos (vfd.ifas.ufl.edu)

• Irrigation Management more Important than Specific Nutrient Rate

• Fertilizer “rate” studies on farms- Caution!