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Precision Orchard Management:Research update

Dr. Brent BlackUtah State University

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Overview

• Definitions and examples

• GIS-based applications

• Weather-based decision support tools

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Precision management

• Components

– Sensors and remote sensing

– Precision positioning

– Integrated communication

– Geomapping

– Auto-steering

– Variable rate technology

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Precision management

• Mapping components

– Soil properties map

– Grid soil testing (nutrients)

– Yield history

– Pest distribution

• Variable management

– Variety

– Seeding rate

– Fertilizer rate

– Pesticide rate

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Orchard examples

• TRAPs app

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Precision Crop Load Management• Determine target crop load

– Bushels per acre to maximize “crop value” (target size class)

– Fruit # per acre → Fruit # per tree → Fruit # per branch

• Precision pruning– Determine flower buds per tree (5 trees per block)

– Factor this into pruning strategies to reduce flower buds

• Precise thinning program– Fruit Growth Model

– Carbohydrate Thinning Model

– “Window” hand thinning

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Orchard examples

• TRAPs app features

• Precision crop load management

• Variable rate management

– Fertilizer

– Based on what? • Soil variability

• Yield history?

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Applications for Utah• Appropriate for tart cherry?

• Research locations

– Three farms

– Two orchard blocks per farm

– Orchard blocks differ in soil uniformity

(based on NRCS maps)

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Mapping parameters - Soil• Soil properties

– Electromagnetic probe• Texture

• pH

• Salinity

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Mapping parameters - Soil

• Soil properties

– Electromagnetic probe

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Mapping parameters - Soil

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Mapping parameters - Canopy

• Aerial imaging

• Light interception mapping

– Light sensors 5-cm spacing

– GPS and data logger

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Mapping parameters - Canopy

• Aerial imaging

• Light interception mapping

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Mapping parameters - Canopy

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Mapping parameters - Yield

• Yield variability

• Technology?

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Mapping parameters - Yield

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Mapping parameters - Yield

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• Mapping Parameters:

Canopy Soil Yield

• Next steps?

– Correlations among these and yield, tree health

– Changes in leaf area over time?

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• Leaf area changes

– Proportional to water needs

• Improved crop coefficients

ETcrop = ETref × Kcrop

Apple

Sweet Cherry

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• Variable rate management

– Fertility

– Irrigation

– Pruning

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• Pruning

– Canopy density threshold

• Fruit color

• Powdery mildew

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Gi.3 Gi.5 Mah

Tree

ligh

t in

terc

epti

on

(%

)

Rootstock

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Overview

• Definitions and examples

• GIS-based applications for tart cherry?

• Weather-based decision support tools

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Weather Based Decision Support

• TRAPs app

– 10 Insect pests

– 1 disease

• Crop growth models?

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• Carbon balance affects thinning response

• Surplus = difficult to thin

• Deficit = easy to thin

Apple Carbohydrate Model

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• Predicts time to pollination

• Used to time bloom thinners

Pollen Tube Growth Model

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ETcrop = ETref × Kcrop

• Orchard-specific ETref calculations

• Projected ET from weather forecasts

Improved ET estimates

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• Growing Degree Days (GDD) from 1-Jan to crop growth stages – apple (by cultivar: Cripps Pink, Gala, Red Delicious)

• GDD to bloom for peach and cherry

Crop Phenology

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• Uses GDD, fruit measurements and date to estimate harvest fruit size distribution. (Cripps Pink, Gala, Red Delicious)

Fruit Growth Model - Apple

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• Bee activity based on weather

– (rain, wind, temperature, sunlight)

• Past three days,

• Forecast of next three days

• Limiting factor

Honey Bee Foraging Activity

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• California model

– GDH for first 30 days after bloom

– Predicts fruit size potential

– Used to determine thinning timing and severity

Peach fruit development

R2 = 0.5944

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Kingsburg

Modesto

Yuba City

F B

D to

R

D (

D a

y s

)

G D H 30

Days

fro

m b

loom

to

“reference”

R2 = 0.6254

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Yuba City

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u i

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m )

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Weather-based toolsUDAF Specialty Crop grant (2019-2021)

• Integrate new heat unit models into Climate Center Website

• Validate these models under Utah Conditions

• Refine/Improve the models where appropriate

• Integrate validated models into Utah TRAPs app.

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Which weather-based toolsGeneral

– Improved ET estimate and forecasts

– Chill unit accumulation

– Bee activity

Apple– Pollen tube growth (bloom thinning)

– Carbohydrate model (thinning)

– Bloom date

– Fruit growth (estimate final size)

Peach– Bloom date

– Fruit development (thinning severity)

Cherry– Bloom date

• Priority: High, Medium, Low, No Interest34

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