Photoselective Netting

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Pract ic ing agr icu l ture is becom ing more

chal leng ing due to -

Global cl imate changes; Extreme

c ilmat ic events .

Urbanizat ion pushing Ag towards

margin al areas.

Market standards go ing up: betterquali ty, less chemicals,

env ironmental-f r iend ly p ract ices.

2Y. Shahak 18.1.11



What can we do about i t?

We cannot do much about the cl imate,

bu t we can p rotect the crops , making themless dependent on their env i ronment.

Protect ion can be prov ided by

Net- (screen-) houses

Greenhouses

Develop ing resistant (to lerant) cu lt ivars.

3Y. Shahak 18.1.11



Nett ing is used to p rotect crops againstexcess ive radiat ion , environm ental hazards

and f ly ing pests

We have taken it one step fu rther, to alsophoto -select ively screen sunl igh t

This is a sophistication of a “low - tech”

pro tected agr icu l ture

4Y. Shahak 18.1.11



Plant -l igh t Interact ion

Sunl ight is the source of energy fo r plant l i fe .It also prov ides signals fo r plants to sense theirenvi ronment,

and to respo nd best for their survival .

Plants can sense even sm al l changes in theirsur round ing l ight reg ime :

Spectra l compos i t ion (quali ty)

Direct ion Ligh t intensi ty (quant i ty)

Durat ion (per iod )

5Y. Shahak 18.1.11



Addi t ional players in agr icu l ture

Who else is respo nding to l ight qu al i ty? Fung al diseases

Insect p ests

Insect-borne Viral dis eases

Benefic ial ins ects

The final crop perform ance integrates al l of theabove

6Y. Shahak 18.1.11



*Polysack Plast ics Industr ies, kibbutz Nir Yi tzhak 7

Photoselect ive nett ing is a new agro- techn olog icalapproach

Developed by a col labo rat ion between the Volcani

Center and an Israel i Plast ics indus try*

We have designed several ser ies o f shade/pro tect ive

net products , each screening di f ferent parts o f the

spect rum

“colored ColorNets ”: Blue , Green , Yellow , Red , purp le

“neutral ColorNets ”: White, Grey , Pearl

and tested them under f ield con di t ions

Y. Shahak 18.1.11



8

Major goals:

Achieving speci f ic physiological benef its , in

add i t ion to the basic protect ive funct ion ofthe nets,

To make the investment in the net-cover ing

cost-ef fect ive the growers.

Y. Shahak 18.1.11



what is un ique about them?

Net type Main purpose

Light q ual ity m odi f icat ion

Sp ectrum? Scatter in g?

B lack Shad ing No No

Clear(“crystal”) Insect screens;hai l protect ion

No Yes

Photoselect ive

( =Colo rNets)

Imp rov ing crop

per formance Yes Yes

Light under the ColorNets is both spectral ly modi f ied andscattered.

The spectra l modi f ication promotes phy s io logical responses.

The scatter ing improv es the penetrat ion o f the spectral ly- modif ied l ight into the inner plant canopy.

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Examples for resul ts in

Ornamentals

10Y. Shahak 18.1.11



Ornamental fo l iage crops (shade p lants)

Aral ia grown for decorat ive branches under 60% shade nets .

Photographed 10 month s after net app l ication

Yellow net Black net Blue net

Both Red and Yellow nets enhance the overal l vegetative

vigor (stem leng th, width, and leaf size)

The Blue net reduce vigo r relat ive to the B lack net

These nets do not m odify R and/or FR !!

Bo th results are desirable, to f i t varying market demands.

Y. Shahak 18.1.11 11



Perennial o rnamentals

The branching su rpr ise

Two of the “neutral ColorNets ” were found to enhance

branching: the Grey and Pearl nets

This is a desired response in th e product ion of cu t t ings and

po tted plant .

10

20

30

40

50

60

70

Green Red Blue Grey Black Aluminet

N o

. o f b r a n c h e s / p l a n t

Pit tosporum var iegatum under

50/75% shad ing

Y. Shahak 18.1.1112



14

Combined covers in ornamentals:

3 retractable screens in one greenhou se: a Blue net used dur ing the vegetat ive stage; Red net towards

f lower ing ; and a thermal sc reen for ch i l l /heat contro l dur ing dayand/or night through out the whole season.

Orchids in B razi l

(Phalaenopsis)

Y. Shahak 18.1.11



Vegetables

15Y. Shahak 18.1.11

http://www.caswells-moms.com/e-shop/images/categories/FreshFruitVegetable.jpg



Vegetables: Leafy c rops

Higher yield under the Red and Pearl nets, com pared

with the black or B lue nets of the same shading capacity

Let tuce cov ered b y a 30% shade

net on to p o f a clear f i lm

282

393 418

258

0

100

200

300

400

שת ר

%03לל

נה י נ פ %03

ה מ ו ד %03

לה ו ח כ

ש

ל

ש

מ

,

ם

282

393 418

258

0

100

200

300

400

שת ר

%03לל

נה י נ פ %03

ה מ ו ד %03

לה ו ח כ

ש

ל

ש

מ

,

ם

Blue Red Pearl No net H e a

d w e

i g h t ,

g r

Red Pearl Black

2

3

4

5

Y i e l d

, K

g / m

2

Red Pearl Black

2

3

4

5

Y i e l d

, K

g / m

2 Summer Basi l in net- tunnels

(50% shading )

16Y. Shahak 18.1.11



Vegetables: Bel l pepper

Summer-autumn pepper were tradi t ionally grow n und er blackshade-nets (~35% sh ading ) at the Besor area (arid).

We have stud ied the performance of p epper und er 3 selectedColorNets: Red , Pearl and Yellow

(A) Plant response stud y (un der prophylact ic pest contro l )

(B) Pest response stu dy (no pest ic ides!)

Besor Experimental Station, Israel 2005-2008

A B

17Y. Shahak 18.1.11



Plant respon ses to photose lect ive shading

Export-qual i ty Net

%Ton/Ha

100 45 Black

154 69 Red

171 77 Yellow

* High -quali ty yield 2007

More frui ts produced per plant per season , and higher yield

(Ton /Ha): 15-40% more th an b lack nets,The order of produ ct iv i ty : Red > Pearl > Yellow >> Black

Export-qual i ty frui t yield: Pearl and Yellow were the best

Als o less po st-harvest decay in frui t grown und er the Pearl

and Yellow nets .

'Vergasa' cumulative yield

0

10000

20000

30000

40000

50000

60000

29.8.06 29.9.06 29.10.06 29.11.06 29.12.06

Harvesting date

F r u i t / d u n a m

Red

Pearl

Yellow

Black

Total yield: # fru it / dunam

18Y. Shahak 18.1.11



Pest Response summary

Even though th e net holes were large enough to al low free

passage of the pepper pests,Infestation w as selectiv ely affected by the Pearl and Yellow shade nets .

Both Pearl and Yellow nets reduced aphid-borne viral diseases!

They al low a more environmental-fr iend ly pest con trol .

19

0

20

40

Red Black Yellow Pearl

% of CMV-infected Pepp er plants

Jun-0

20

40

60

Red Black Yellow Pearl

% of PVY-infected Tomato p lants

Y. Shahak 18.1.11



Orchard Nett ing Research in Israel

• Table grapes

• Peach

• App le

• Pear

• Pomegranate • Pers immon

• Loquat

• Banana

• Avocado

• Citrus

• Frui t tree nu rser ies

20Y. Shahak 18.1.11



Fru it t rees - Summary

Pho toselect ive t ree responses

(which depend on the color of the cover ing net)

Flowering

Fruit-set

Product iv i ty

Time of maturat ion (early & late)

Fruit s ize

Vegetat ive grow th

Water-use-eff ic iency

21Y. Shahak 18.1.11



Protect ion from hai l, w ind, birds,

etc.

No sunburn s, less w ind s cars,

smoo ther fru i t sk in

Water saving

Frui t trees

Addi t ional benefi ts from the nett ing(independent of the co lor of the net)

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23

Photoselective respon ses:

Effects on the rate of frui t maturat ion and berry s ize Exp: early table grapes (Jordan Valley and Arava 2000-2006 )

Advanced maturat ion(sug ar accum ulat ion)

under Whit e and Pearlnets (wh ite nets family ),

Delayed m aturat ion under Red and Grey nets,

Larger berr ies and better frui t qual i ty un der the l ight -dispersivenets (wh ite, Pearl, Red, Yellow nets); reduced s ize under Grey

and black

Fol lowing th is research, al l vineyards at the Jo rdan Val ley andArava region s are now covered by nets,

10

12

14

16

18

20

10.5.04 17.5.04 24.5.04 31.5.04Date

S u g a r c o n t e n t , % T S S

Red Grey Pearl No net

Prime 2004

Y. Shahak 18.1.11



App l icat ions by grow ers

Late table-grape cu lt ivarsLakhish “ Tali Grapes” , Israel 2009

24

Red net for delaying fru i t maturat ion , Wh ite net for

advancing maturat ion; bo th also improv ing berry size

and quali ty,

+ prevent ing sunburns , w ind-scars, and bird d amage.

Y. Shahak 18.1.11

Ph t l ti f f t



25

Photoselective ef fects :

Fruit size & y ield in GD Apples Average of 5 su ccess ive years (2002-2006)

0

20

40

60

80

100

Pearl Red Wh ite B lu e No -n etB lac k Gr ey

K g / T r e e / Y e

a r b b bc

c c c

a

Ton / Ha /year

94 84 83 79 70 67 66 2005 Size distribution

0

10

20

30

40

50 55 60 65 70 75 80 85

Fruit Diameter, mm

K g / T r e e

ת ר ו ק י ה נ י נ פ ה ר ו ח ש

Black

Pearl

No net

Larger frui t size and fru i t yield under the l ight-dispersiveColorNets, but no t under black and Grey nets.

Order of eff ic iency :

Pearl > Red , White > Blue > No-net > Black , Grey

Y. Shahak 18.1.11



Final words

Photoselect ive nett ing enables better ut i l ization of

solar energy by ho rt icu l tura l crop s,

whi le reducing chem ical appl icat ions (PGRs,

pest ic id es, fungic ides).

And prov id ing pro tect ion from envi ronmentalhazards

The new techn ology can be adjusted to f i t di f ferent

crop s/cul t ivars, cl imates, market demands

We are current ly test ing the techn ology in m ore

crop s, and fur th er develop the next generat ion o f

photos elect ive nett ing m ater ials .

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28

Take-home message

The qual ity o f the ligh t w ith in the

shade can make a lot o f dif ference!

Y. Shahak 18.1.11

B’sor Experimental Station, Negev

P bli ti



Publications (partial list)

Y. Shahak

• Oren-Shamir et al. (2001) Coloured shade nets can improve the yield and quality of green decorative

branches of Pittosporum variegatum. J. Hort. Sci. Biotech 76: 353-361

• Shahak et al. (2004) ColorNets: A new approach for light manipulation in fruit trees. Acta Hort. 636: 609-

616.

• Shahak et al. (2004) ColorNets: crop protection and light-quality manipulation in one technology. Acta

Hort. 659 (1): 143-151.

• Rajapakse and Shahak (2007) Light quality manipulation by horticulture industry. In: Light and Plant

Development (G. Whitelam and K. Halliday, eds.), pp 290-312, Blackwell, UK. (A book chapter).

• Elad et al. (2007) Effect of colored shade nets on pepper powdery mildew (Levillula taurica).

Phytoparasitica 35 (3): 285-299.

• Shahak (2008) Photoselective netting for improved performance of horticultural crops. A review ofornamental and vegetable studies carried in Israel. Acta Hort. 770: 161-168.

• Ganelevin (2008) World-Wide Commercial Applications of Colored Shade Nets Technology

(ChromatiNet). Acta Hort. 770: 199-203.

• Shahak et al. (200 8 ). Improving solar energy utilization, productivity and fruit quality in orchards and

vineyards by photoselective netting. Acta Hort. 772: 65-72.

•Retamales et al. (2008) Colored shading nets increase yields and profitability of highbush blueberries. Acta Hort. 770:193-197.

• Shahak et al. (2008) Photoselective shade netting integrated with greenhouse technologies for

improved performance of vegetable and ornamental crops. Acta Hort. 797: 75-80.

• Ovadia et al . (2009) Coloured shade nets influence the stem length, time to flower and flower size of

ornamental crops. J. Hort. Sci. Biotech., 84(2): 161-166.

• Fal l ik et al . (2009) Can colored shade nets maintain sweet pepper quality during storage and

marketing? Acta Hort. 830: 37-43.29

Photoselective Netting

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