Web-based Irrigation Scheduling Terence Robinson, Alan Lakso Mario Miranda and Mike Fargione Dept. of Horticulture, Cornell University Geneva, NY 14456 NY-ARDP

The Need for Irrigation in the Northeast: 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.

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

Fruit Size in the Severe Drought of 2007 Fruit size of Gala in 2007 was 70g less than in 2010 (2 inch vs. 3 inch Gala

Common Mistake with Tall Spindle: No Irrigation and No Fertigation Rapid Leaf area development with branched trees Limited 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

Estimating Tree Water Requirements: 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.

Calculation of Water Usage using Lakso-Dragoni Model: Considers: Rainfall Calculates evapotranspiration from weather data Crop coefficient to adjust calculated evapotranspiration Efficiency of irrigation systems: Trickle=0.9 Sprinklers=0.6 to 0.7 Weekly Evap. (inches) Weekly Precip. inches Amount of Irrigation Water per Week (inches/week) _ = Efficiency of Irrigation System

Using the Lakso-Dragoni Model via the Web: Cornell Web Server (NEWA) Lakso-Dragoni Evapotranspiration Model (calculates TRV, fraction of mature leaf area, evapo-transpiration) Grower owned weather station Grower inputs: Tree spacing (inrow x between row) Tree height and width Emitter spacing and output Date of Budbreak Model Provides: Inches of water needed daily since budbreak Hours 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 1-May -0.9 1.4 18-May 0.0 3.0 2-May -0.7 1.2 2.6 19-May -2.5 4.1 7.1 3-May -0.6 1.0 3.6 20-May 11.2 4-May 0.3 -0.5 3.1 21-May -2.2 3.5 14.7 5-May 4.0 22-May -2.6 4.3 19.0 6-May 1.9 -3.1 0.9 23-May -3.2 5.3 24.3 7-May 24-May -2.8 4.6 28.9 8-May 5.0 -8.2 -7.3 25-May -3.3 5.4 30.3 9-May -0.1 0.2 -7.1 26-May -2.9 4.8 35.1 10-May -1.2 2.0 -5.2 27-May 5.2 40.3 11-May -0.4 0.7 -4.4 28-May -2.7 44.6 12-May -0.3 -4.7 29-May 5.1 49.7 13-May 1.5 -2.4 30-May 4.5 54.3 14-May -1.8 -4.1 31-May 59.3 15-May -1.1 1.8 1-Jun 56.9 16-May -1.9 2-Jun 58.4 17-May -1.4 2.2 3-Jun 60.4

Using the Model: Keep the Tank Full or ¾ Full

Fertigation Strategy First 3 Years: 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 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)

Future Plans 2011 2012 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.

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.