Báo cáo khoa học nông nghiệp " Watermelon Production Workshop " pdf

Variety Selection• Affects yield and quality • Match variety to climate • What is fashionable eg seedless watermelon in Australia and US • Examples…... Effect of planting density on yiel

Watermelon Production Workshop

• Pest and Disease management

• Harvesting and quality assessment

• Transport and handling

• Economics

Variety Selection

• Affects yield and quality

• Match variety to climate

• What is fashionable (eg seedless watermelon in Australia and US)

• Examples…

Shadow

Nightshade

Syngenta 1201

Dragon Heart

SPS 601-2

Crop Establishment

• Direct seed (plant seed directly into field)

• Transplanting (grow a seedling and plant that)

Root systems Direct seed v’s transplant

• Direct seed Æ strong taproot and deeper

root system

– Good to plant 2-3 seeds per hole and then thin

later

• Transplant Æ shallower root system

based on lateral roots

Vegetable Seedlings

Transplanting

watermelons

How does establishment type affect

the plant

Direct Seeded

Melon

• What can you see ?

• Strong taproot !

• Note strong

taproot is still

there

• What would that

mean for crop

development and

management ?

Watermelon Transplants

Seedlings ready

for planting Old seedlings

Mature Rockmelon Plant established from a transplant

• Notice lateral

roots

• Implications ?

Melon Roots

• Watermelons have

a small root system…

• Usually about 2%

of total plant dry weight

• Need to manage it well

Watermelon seedling on plastic

mulch

Crop ready near harvest

Seeded melon ready for harvest

Planting Density

What is the best plant population?

Standard Density in Australia

• 1.8m between rows (bed about 1.2m across)

• 1.0m between plants

– Æ 5500 plants/ha

Typical planting

in Australia

Effect of planting density on yield

Density doesn’t matter

more fruit but harvest is spread over a longer time

High Density: Need

higher inputs (water + fertilizer and harvest more concentrated

Planting Density and Irrigation

DS pollinators

Can get higher yields if

extra water applied to

higher density

Deciding on optimum density

• Need to consider:

• Fruit or edible part size (density as a tool)

• Yield

• Input costs Æ highest net return (must

remember why farmers grow crops – why ??)

Typical watermelon crop

in Australia

• Vine covers the

whole soil area

• This crop grown on organic mulch

Pollination

Watermelons have male and female

flowers Watermelons need

BEES to pollinate female flowers

2 hives per ha

Irrigation Management

• There are 2 aspects to irrigation management:

1 Develop a healthy root system

2 Maximize yield and fruit quality

Key points for healthy roots

• Fill the soil profile at planting

• Allow roots to explore the moist soil volume

without small top-up irrigations

• What can happen to soil aeration during

irrigation ? How might this affect root growth ?

Growth and sugar accumulation

Once the plants are flowering, they should be kept free of water stress until the end of harvest

Water stress closes stomata in leaves which let in

CO2 –

Less CO2 Æ less photosynthesisÆ less sugar for fruit growth and sweetness

Irrigation of water stress on melon

fruit soluble sugars

Stress 1wk before harvest

Stress 1wk before &

through harvest

sweetness and yield

More water stress reduces fruit

sweetness and yield

More water stress reduces fruit

sweetness and yield

Irrigation Management Summary

• Start plants off with a well watered soil profile This will

determine the size the root system.

• Allow plants to use available water during vegetative

stage, but water if required.

• Maintain plants free of water stress from flowering thru to harvest.

• Avoid short irrigations – longer is a more effective use of the water

• Calcium very important for fruit quality

• Molybdenum often low – foliar sprays when

young

• Use leaf tissue analysis or sap test to monitor

Leaf Nutrient Levels

Nutrients Suggested leaf nutrient level

Pests and Diseases

• Heliothis (Helicoverpa sp) e.g corn earworm

• Aphids (spread viral diseases)

• Whitefly ?

• Mites and thrips

• Mice – eat new seed

• IPM to manage pests

Powdery Mildew

Harvesting

How to assess maturity

• Cut fruit and assess

• Look for skin colour

• Tap fruit

• Pick slightly early if sending to market – might

need to last 7-10 days before eating

Transport and Handling

Handling and Transport

• Pack in straw and cartons protects fruit

• In Australia transported in 500kg cardboard bins

• Temperature: around 20 deg C is OK

Hanoi Market

The economics of a good return for

watermelon

Good quality at harvest ensures a

good price for the grower

Good quality seed 100 Minimal pesticide 500 Minimum fertiliser 100 Other costs 500 Cost per Sao = 1200

Poor quality and Low price

Price per Sao = 2500 Net return per Sao = 1300

Cost per Sao = 2100

Best quality and Best price

Price per Sao = 5000

Net return per Sao = 2900

Cutting costs in the field creates a poor quality low priced product

For a successful crop all inputs must be included

Best Practice

= Fewer Sao

Cutting costs in the field creates a poor quality low priced product

For a successful crop all inputs must be included

Minimum inputs Best Practice

„ Achieving best prices for Vinh

vegetable growers

will pay top prices

1. Supply good product

1. It is easier to get

customers to want (pull)

your product than force

it on them (push)

2. Like buffalo – easier to

lead than push

1. Excellent quality

2. High yields

3. Clean & Safe to eat

= Vinh Cabbage

1. Link to best market - Metro

3 Posters in Metro

4 Educate Metro staff

= More Dong

Vinh Cabbage Production (estimate)

0 2,000 4,000 6,000 8,000 10,000 12,000 14,000 16,000

28/01/2007

30/01/2007 1/02/2007

3/02/2007

5/02/2007

7/02/2007

9/02/2007

11/

02/2

007

13/02/2007

15/02/2007

17/02/2007

19/02/2007

21/02/2007

23/02/2007

25/02/2007

27/02/2007 1/03/2007

3/03/2007

5/03/2007

7/03/2007

9/03/2007

11/03/2007

13/03/2007

15/03/2007

17/03/2007

The production safe, high quality

watermelons for Nghe An

Good quality at harvest ensures a

good price for the grower

Important Issues for the Market

1.Reliable supply and as agreed

2.Quality – especially sweet (high Brix) and

How to achieve ?

• Follow the growing guidelines

• Do not spray pesticides outside the growing

guidelines

• Must fill out the growing record accurately

Marketing strategy to promote sales

• Labels to identify produce

• Traceability

• In store promotions / posters

• Information on handling provided to Metro staff

• Advertising

Outcomes if program followed

• An agreed supply program (100 tonne) and price with Metro Æ more reliable income for farmers

• GAP costs more to implement but will result in

higher quality, better yields and higher income

• Must produce safe, high quality produce

because Metro must be able to charge

consumers a higher price for this assurance

2 key objectives for today

1 Negotiate with Mr Thai and agree on price

strategy Metro will pay farmers

2 Agree on the consequence of a farmer not

following the program, especially if a high

pesticide residue is found - GAP