Web-based Irrigation SchedulingTerence Robinson, Alan Lakso Mario Miranda and Mike Fargione

Dept. of Horticulture, Cornell University Geneva, NY 14456

NY-ARDP

• In the average season (May-September), rainfall is 5-6 inches less than pan evaporation.

• In 3 years out of 5, significant water shortages occur in June, July and August.

• In the worst situations, the shortfall can be 1.5-2.0 inches per week.

The Need for Irrigation in the Northeast:

Water Deficits in a Dry Year (2007) and a Wet Year(2010)

• Fruit size of Gala in 2007 was 70g less than in 2010 (2 inch vs. 3 inch Gala

Fruit Size in the Severe Drought of 2007

Common Mistake with Tall Spindle: No Irrigation and No FertigationRapid Leaf area development with branched

treesLimited root system due to digging in nursery.

Highly feathered trees experience water stress in late May and June due to limited root systems and extensive leaf area

Water must be applied frequently to limit water stress on newly planted trees. Trickle irrigation must be installed within 2 weeks of planting

Newly planted trees have limited capability to take up nutrients due to damaged root systems.

Water and Nutrient stress with different tree types

Little stress More stress

Effect of Trickle Irrigation on Growth and Yield of Empire, Mutsu and Delicious Trees

Shoot Shoot Av.

Growth Growth Yield/ Yield/ Fruit

yr. 1-3 yrs4-5 tree yr. tree yr. Size

Treatment (m) (m) 2-4 (kg) 5-6 (kg) (g)

(% of Control)

Unirrigated 100 b 100 b 100 b 100 b 100 b

Trickle Irrigation 160 a 139 a 145 a 160 a 107 a

• Modified Kenworthy Rule – 1 gallon water/tree/day/year of tree age.

• Soil suction tensiometers– Apply irrigation when tensiometers read 20 centibars.

• Pan Evaporation– Open surface evaporation adjusted with a crop coeficient (Kc).

• Evapotranspiration models– Penman-Monteith model developed for grass adapted to

orchards with a crop coeficient (Kc)

– New Lakso/Dragoni evapotranspiration model for apples.

Estimating Tree Water Requirements:

Amount of Irrigation Water per Week(inches/week)

=

WeeklyEvap. (inches)

Efficiency of Irrigation System

Calculation of Water Usage using Lakso-Dragoni Model:

Weekly Precip. inches_

Using the Lakso-Dragoni Model via the Web:

Cornell Web Server (NEWA)

Grower owned weather station

Lakso-Dragoni Evapotranspiration Model(calculates TRV, fraction of mature leaf area, evapo-transpiration)

Grower inputs:Tree spacing (inrow x between row)Tree height and widthEmitter spacing and outputDate of Budbreak

Model Provides:Inches of water needed daily since budbreakHours of irrigation needed since budbreak

Output of Lakso-Dragoni Model in 2010 at Williamson, NY

Date

Water Balance ET-Rainfall (gal/tree)

Irrigation Hours Needed

Cumulative Irrigation Hours Needed Date

Water Balance ET-Rainfall (gal/tree)

Irrigation Hours Needed

Cumulative Irrigation Hours Needed

1-May -0.9 1.4 1.418-

May 0.0 0.0 3.0

2-May -0.7 1.2 2.619-

May -2.5 4.1 7.1

3-May -0.6 1.0 3.620-

May -2.5 4.1 11.2

4-May 0.3 -0.5 3.121-

May -2.2 3.5 14.7

5-May -0.6 1.0 4.022-

May -2.6 4.3 19.0

6-May 1.9 -3.1 0.923-

May -3.2 5.3 24.3

7-May 0.0 0.0 0.924-

May -2.8 4.6 28.9

8-May 5.0 -8.2 -7.325-

May -3.3 5.4 30.3

9-May -0.1 0.2 -7.126-

May -2.9 4.8 35.1

10-May -1.2 2.0 -5.227-

May -3.1 5.2 40.3

11-May -0.4 0.7 -4.428-

May -2.7 4.3 44.6

12-May 0.2 -0.3 -4.729-

May -3.1 5.1 49.7

13-May 1.5 -2.4 -7.130-

May -2.8 4.5 54.3

14-May -1.8 3.0 -4.131-

May -3.1 5.0 59.315-May -1.1 1.8 -2.4 1-Jun 1.5 -2.4 56.916-May -1.9 3.1 0.7 2-Jun -0.9 1.5 58.417-May -1.4 2.2 3.0 3-Jun -1.2 2.0 60.4

Using the Model: Keep the Tank Full or ¾ Full

• Liquid Nitrogen Years 1-3– UAN 30-0-0– CAN 17-0-0– CN 9-0-0-11Ca (Honeycrisp)– APP 10-34-0– N=60-100 lb/acre/year over 10 weeks or 6-10

lb/acre/week• Potassium beginning in year 3

– Liquid KCl 0-0-60– Liquid K Tiosulfate 0-0-25-17S– Potassium Phosphate 0-20-20– K2O=60 lb/acre/year over 15 weeks or 4

lb/acre/week• Small amounts of water applied twice weekly.

– 5 gallons per tree per week in year 1– 10 gallons per tree per week in year 2

Fertigation Strategy First 3 Years:

Venturi Injector

Effect of Irrigation and Fertigation on Growth and Yield of Delicious Trees

Shoot Shoot Av.

Growth Growth Yield/ Yield/ Fruit

yr. 1-3 yrs4-6 tree yr. tree yr. Size

Treatment (m) (m) 2-4 (kg) 5-7 (kg) (g)

(% of Control)

Unirrigated 100 c 100 b 100 b 100 b 100 b

Trickle Irrigation 137 b 131 a 98 b 115 ab 101 b

Fertigation 171 a 140 a 124 a 127 a 104 a

3 Yr. Old Empire (Unirrigated) 3 Yr. Old Empire (Fertigated)

2011• Finish Web-Interface for Use of Model via Web.• Extension Educators to Use Model and provide area-wide estimates

of water balance.– Publish weekly Water Balance for a Mature Vertical Axis Orchard (gallons/acre or

inches/acre)

– Send weekly reports to cooperating growers for experimental blocks

2012• Open web access to model to all NY growers and consultants for

individual orchard estimates of Irrigation requirement.• Extension Educators to Continue Use of Model and provide area-

wide estimates of water balance.– Publish weekly Water Balance for a Mature Vertical Axis Orchard (gallons/acre or

inches/acre)

– Send weekly reports to cooperating growers for experimental blocks

Future Plans

Conclusions:• Highly feathered, tall spindle trees can undergo water stress

soon after growth starts limiting first year growth.

• Trickle irrigation has its largest impact in the first few years and so should be installed early in the first year.

• In drought years, the application of water should begin in mid-May. In other years, the application of water can be delayed until late May.

• Fertigation is an efficient way to deliver Nitrogen, Phosphorus and Potassium fertilizers to apple.

• Fertigation can give larger fruit size and greater yield.