Measuring Cantaloupe Growth
from Emergence to Harvest
Jeffrey C. Silvertooth
University of Arizona
Tucson, Arizona
Cantaloupe (melon)
Production - Arizona
• Spring melons
• ~ 10,000 acres
• Yield ~ 230 cwt./acre
• Fall melons
• ~ 4,000 to 5,000 acres
• Yield ~ 214 cwt./acre
Crop System Efficiency
Critical Limiting Factors in
Desert Agriculture
• Provide inputs that you need
• Water (Irrigation management)
• must consider positive crop response
• Timing is critical
• Must follow crop condition
• requires crop monitoring
• Nitrogen
• Pest Control / Management
Crop Management –
Strategies
Feedback Management
Requirements
• Scheduled Approach
• useable / accessible measurement
• established baselines / guidelines
• Based on calendar dates or days after
planting (DAP)
• Feedback Approach
• Based on crop condition
• Stage of growth
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
• reference base
• common variety types (species)
• regionally specific baselines
• validation of recommendations
1
Dynamic Nature of the Melon
Plant
• Due to it’s indeterminate nature, melon
plants are very sensitive/responsive to
environmental conditions
• Plant will retain or abort fruit in response to
current conditions
• Melon plants are sensitive or responsive to
management
• Managing veg./repro. balance critical
Vegetative / Reproductive Balance
• What is normal?
• How do you measure it?
Melon Plant Growth / Mgt.
• Allocation of nutrients and resources
to vegetative/reproductive
components
• in response to environmental conditions
• Represents a major challenge in melon
production
• Irrigation
• Fertilization
• Pest management/control
• Vigor/disease management
Crop Monitoring - Objectives
• Predict important stages of growth
• Yield Projections
• What do you do about it?
Great State of Arizona
Development of Baselines for
Reference – Arizona conditions
Development of a representative
database (regionally specific)
• Regular sampling of plant growth and
development data
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
2
Development of Baselines for
Reference – Arizona conditions
• Plant measurements on 14 d intervals
• Node numbers
• Vine length
• Female blooms
• Melon number
• (> golf ball sized melons / 3-4 cm dia.)
• Primary and all fruiting vines
• Usually up to 5 fruiting vines
Vine Measurements
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
3
General melon plant development as a
function of heat units
Planting
Date
0
First
Bloom
Golf-ball
size melon
Early
Netting
360
625
800
Commercial
Harvest
1245
Heat Units Accumulated After Planting
(HUAP 86/55°F)
2003 melon plant development as a
2003 melon plant development as a
function of heat units
function of heat units
Planting
Date
Planting
Date
First
Bloom
Golf-ball
size melon
Early
Netting
0
367
632
852
Heat Units Accumulated Planting
HUAP 86/55°F
First
Bloom
Golf-ball
size melon
Early
Netting
Commercial
Harvest
Commercial
Harvest
0
1395
430
650
790
1273
Heat Units Accumulated After Planting
HUAP 86/55°F
Aaron-Yuma Valley (Variety = S0l Real), sub date = 2/24/03
Waymon-Yuma Valley (Variety = Ocotillo), sub date = 1/26/03
Planting
Date
First
Bloom
0
341
Golf-ball
size melon
561
Early
Netting
812
Commercial
Harvest
1184
Heat Units Accumulated After Planting
HUAP 86/55°F
Perriconni-Yuma Valley (Variety = Gold Rush), sub date = 3/5/03
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
4
2003 melon plant development as a
function of heat units
2003 melon mainstem node development
as a function of heat units
30
First
Bloom
Golf-ball
size melon
Early
Netting
Commercial
Harvest
0
352
629
811
Heat Units Accumulated Planting
HUAP 86/55°F
25
Mainstem length (cm)
Planting
Date
1209
3W-Harquahala (Variety = Zeus), sub date = 2/19/03
20
15
10
Zeus-Harquahala
Rocket-Harquahala
Sol Real-Yuma Valley
Gold Rush-Yuma Valley
Ocotillo-Yuma Valley
5
Planting
Date
First
Bloom
Golf-ball
size melon
Early
Netting
Commercial
Harvest
0
305
649
764
Heat Units Accumulated Planting
HUAP 86/55°F
0
0
200
400
600
800
1000
1200
1400
Heat Units Accumulated After Planting (HUAP 86/55oF)
1162
2003 melon mainstem node development as
affected by HUAP.
15W-Harquahala (Variety = Rocket), sub date = 3/5/03
2003melon mainstem flower development
as a function of heat units
2003 melon mainstem development
(length - cm) as a function of heat
units
140
5
120
Mainstem length (cm)
Mainstem flower count
4
3
2
Zeus-Harquahala
Rocket-Harquahala
Sol Real-Yuma Valley
Gold Rush-Yuma Valley
Ocotillo-Yuma Valley
1
100
80
60
Zeus-Harquahala
Rocket-Harquahala
Sol Real-Yuma Valley
Gold Rush-Yuma Valley
Ocotillo-Yuma Valley
40
20
0
0
0
200
400
600
800
1000
Heat Units Accumulated After Planting (HUAP 86/55oF)
0
200
400
600
800
1000
1200
1400
o
Heat Units Accumulated After Planting (HUAP 86/55 F)
2003 mainstem flower development as affected by HUAP.
2003 melons per 2m as a function
of heat units
2003 melon mainstem length as affected by HUAP.
Melon Agronomy Program
16
• Development of crop monitoring
system
Mainstem length (cm)
14
12
• based on melon phenology models
• heat unit (HU, 86/55 oF thresholds) basis
10
8
6
Zeus-Harquahala
Rocket-Harquahala
Sol Real-Yuma Valley
Gold Rush-Yuma Valley
Ocotillo-Yuma Valley
4
2
0
0
200
400
600
800
1000
1200
1400
Heat Units Accumulated After Planting (HUAP 86/55oF)
• Development of feedback
management systems
• mgt. based on crop condition
• nutrients, water, insect pests, PGRs, etc.
2003 melon count per 2m as affected by HUAP.
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
5
Crop Monitoring Crop Management
Great State of Arizona
• Stage of growth (HU model)
• Crop vigor estimate
• Vegetative growth index
• Fruit load development (melon prod.)
• Ex. high fruit load = high N demand
• Yield projection
Silvertooth, Jeffrey C. 06/04/03. The 9th
Annual Melon Field Day, Maricopa
Agricultural Center, Maricopa, AZ.
6