monthly AS treatment also provided greater clipping yields

than several of the controlled release N sources (Table 4).

For Experiment 2 there were few treatment differences at

0.5 month after application (Table 5). At 1 month after appli

cation, EPDM-1 provided greater clipping growth than AS, and

some of the short (SCU) and longer (S-l) duration release

materials (Table 5). The monthly AS treatment provided

greater clipping yield compared to the single AS application

on the 2 month sampling date (Table 5). There were no dif

ferences between the two AS treatments on all other dates

(Table 5). At 3 months after application, S-l provided greater

clipping yield than all other N sources except S-2 (Table 5).

Although N tissue contents were not measured, we speculate

that N from AS was efficiently recovered by the turfgrass when

compared to several of the controlled-release N sources eval

uated in these experiments even though the N in AS was

readily available. Furthermore, combining AS with either S-l,

S-2, or S-3 sources did not increase clipping yields compared

to application of the controlled-release N sources alone, even

immediately after application.

In these experiments, in most cases the N sources provid

ed turf quality and clipping yields consistent with their esti

mated release duration under winter and summer climatic

conditions in sub-tropical Florida. Only in a few instances and

generally at the end of an experimental cycle were turfgrass

quality ratings below values considered to be minimally-ac

ceptable even though the rate of N applied was about 50% of

that typically applied to bermudagrass. Although there were

significant differences among sources, no one N source con

sistently outperformed other N sources over the study period.

Based on this research, when considering which N source to

apply, turfgrass managers have numerous options, since no

one fertilizer source stood out with regard to turfgrass quality

and yield. Factors such as cost and environmental impacts

should also be considered.

Literature Cited

Beard, J. B. 1973. Turfgrass Science and Culture. Prentice Hall, Inc. Engle-

wood Cliffs, N.J.

Fry, J. D., D. O. Fuller, and F. P. Maler. 1993. Nitrogen release from coated

ureas applied to turf. J. Intl. Turfgrass Soc. 7:533-539.

Harre, E. A. andj. D. Bridges. 1988. Importance of urea fertilizers, p. 1-

15. In: B. R. Bock and D. E. Kissel (Eds.). Ammonia volatilization from

urea fertilizers. Bull. Y-206. Natl. Fert. Dev. Ctr., TVA, Muscle Shoals,

Ala.

McCarty B. L., R. J. Black, and K. C. Ruppert. 1994. Selection, establishment

and maintenance of Florida lawngrasses. Fla. Coop. Ext. Serv, Inst. Food

and Agr. Sci. Univ. of Florida, Gainesville.

Peacock, C. H. andj. M. Diapola. 1992. Bermudagrass response to reactive

layer coated fertilizers. Agron. J. 84:946-950.

Petrovic, A. M. 1990. The fate of nitrogenous fertilizers applied to turfgrass.

J. Environ. Qual. 19:1-4.

Snyder, G. H. andj. L. Cisar. 1992. Controlled-release potassium fertilizers

for turfgrass. J. Amer. Soc. Hort. 117:411-414.

Snyder G. H., E. O. Bert, andj. M. Davidson. 1981. Nitrogen leaching in ber

mudagrass turf: 2. Effect of nitrogen sources and rates, p. 313-324. In:

R. W. Sheard (Ed.). Proc. 4th Intl. Turfgrass Res. Conf., Univ. Guelph,

Ontario. 19-23 July.

Proc. Fla. State Hort. Soc. 114:258-262. 2001.

SOLARIZATION OF SPENT POTTING MEDIA IN PLASTIC BAGS

AND ORGANIC AMENDMENTS FOR THE PRODUCTION OF BEDDING PLANTS

Gladis M. Zinati and Herbert H. Bryan

University of Florida

Tropical Research and Education Center

18905 SW 280 Street

Homestead, FL 33031

Robert McSorley

University of Florida

Department of Entomology and Nematology

PO Box 110620

Gainesville, FL 32611-0620

Robert T. McMillan, Jr.

University of Florida

Tropical Research and Education Center

18905 SW 280 Street

Homestead, FL 33031

This research was supported by the Florida Agricultural Experiment Sta

tion and U.S. Department of Agriculture, and approved for publication as

Journal Series No. N-02192. The authors would like to acknowledge Mr. Paul

Gherke from Lovell Farms, Inc., for providing potting media, pots, seedlings;

and Mr. William Graves for his technical assistance.

Additional index words. Horticultural parameters, impatiens,

ornamentals, periwinkle, petunia, recycling, soil disinfection.

Abstract. An experiment was conducted to evaluate the effec

tiveness of solarization of spent potting media and the addition

of organic amendments on bedding plants production in

southern Florida. Spent potting media in clear, 0.1-mm-thick

polyethylene plastic bags were solarized for 0, 2 or 4 weeks.

Solarized media were compared to new potting media. In addi

tion, each treatment was compared to humic acid treated me

dia that were arranged in a completely randomized

experimental design with eight replications. Impatiens, peri

winkle and petunia were grown in each of these treatments and

evaluated for their horticultural parameters 9 weeks after

transplanting. Solarization of spent media for 2 or 4 weeks in

creased plant height, width, plant dry weight, and flower num

ber per plant compared with those grown in non-solarized

media, irrespective of the organic amendment. Solarization for

2 or 4 weeks doubled the values of the horticultural parameters

in impatiens and periwinkle plants compared with those grown

in new or non-solarized media. All horticultural parameters val

ues of petunia plants that were grown in solarized media for 2

or 4 weeks and received humic acid were comparable with

those grown in new media. The addition of humic acid signifi

cantly increased petunia plant width, dry weight, and number

258 Proc. Fla. State Hort. Soc. 114: 2001.

of flowers in 2 or 4 weeks solarized media and the latter two pa

rameters in new media. Solarization of recycled media for 2 or

4 weeks in plastic bags has a high potential to be considered

as a useful soil disinfectant, and is an inexpensive, fast, and ef

fective technique for recycling stockpiled disease-infected me dia and providing horticultural parameter values for impatiens

and petunia comparable with plants grown in new potting me

dia. Combining solarization and humic acid for petunia can at

tain even higher horticultural values. The use of this

solarization technique as an environmentally safe media disin

fectant with organic amendments offers an additional option for increasing pest control and crop yield of bedding plants, an

opportunity to reduce input to landfills, and has a great poten

tial to be adopted by nursery growers and homeowners.

Florida ranks second in ornamental plant production in

the U.S. with crop sales of about $1.5 billion (National Agr.

Stat. Ser., 1998). A vast majority of ornamental crops are

grown now in containers with new growing media. The most

traditional potting mix contains peat as the organic compo

nent. Peat is not a quickly renewable resource in the short

term and the demand and use of peat is much greater than its

production rate (Klock-Moore and Fitzpatrick, 2000). In ad

dition, production of high quality plants is expensive, and

stock piling of non-saleable planting media from disease-in

fected containerized plants not only makes this material a

candidate for landfills but also adds extra costs to large-scale

nurseries to get rid of the material. Fumigation of recycled

potting media with methyl bromide (MB) and metam sodium

is among the chemical options that horticultural nursery

growers have adopted to cut costs of plant production, espe

cially where cost of new potting media and its availability are

high. However, MB will phase out in 2005, and metam sodi

um is not available for homeowners. A dependable, cost effec

tive, environmentally sound, alternative technique that can

be applied where chemicals are not allowed and cost of pro

duction using new potting media is costly is needed to pro

duce high quality and pest-free plants.

Studies have shown that soil disinfection such as soil

steaming and metam sodium or formaldehyde application

can be used for container media reclamation (Sneh et al.,

1983). Soil solarization [by covering moist container medium

with transparent polyethylene (PE) film during the hot sea

son] is a recognized soil disinfection method for controlling

soil-borne pests (Katan, 1987). Over the years, increasing at

tention has been focused on soil solarization because of its

relatively benign environmental impact in combination with

other disinfection techniques such as fumigation (McGovern

andMcSorley, 1997).

Soil solarization has been used worldwide and is known to

be a cost-effective technique among horticultural growers for

controlling soil-borne pests. It reduces toxic residues, elimi

nates the need for fumigation, increases levels of available

mineral nutrients in soils (Chen and Katan, 1980; Grunzweig

et al., 1998; Kaewruang et al., 1989) and favors beneficial

organisms (Gamliel and Katan, 1991; Stapleton and Devay, 1984, 1986).

Research showed that solarization or solarization com

bined with half dosage of MB increased plant and flower

yields of Gypsophila paniculata grown in container medium to

a level similar to that obtained with MB alone at full dosage

(Gamliel et al., 1993). In addition, solarizing a potting mix in

PE bags for 3 or 4 weeks eliminated phytophthora (Phytophtho-

ra nicotianae) fusarium (Fusarium oxysporum), and rhizoctonia

(Rhizoctonia solani) from gerbera (Gerbera jamesonii Bol. ex

Adlam.). Kamra and Gaur (1995) showed that plant parasitic

nematodes were controlled by solarization of soil for 2 d in PE

bags.

In the last decade, research on the utilization of solariza

tion combined with organic amendments has increased.

Gameliel and Stapleton (1993) showed that use of chicken

compost with solarization increased yield of successive lettuce

(Lactuca sativa L.) crops. Solarization of cabbage {Brassica

oleracea L.)-amended soil significantly increased watermelon

[Citrullus lanatus (Thunb.) Matsum. & Nak.] yield (Keinath,

1996). Solarization of organic amended soil had a long-term

effect in controlling some of soilborne pathogens in potato

(Solarium tuberosum L.) and peanut (Arachis hypogaea L.)

(Gamliel et al., 1999) and tomato (Lycopersicon escukntum

Mill.) (Sivan and Chet, 1993). However, the combined effects

of solarization of recycled containerized media with the addi

tion of organic amendments for bedding plant production

are not documented to our knowledge.

The objectives of this study were to determine the effects of

solarization of recycled potting media and addition of organic

amendments on horticultural parameters such as plant height

and width; plant dry weight, flower number per plant, and

foliage color of impatiens (Impatiens wallerana), periwinkle

(Catharanthus roseus L.), and petunia (Petuniax hybrida) com

pared to those grown in non-solarized recycled potting media

and those grown in new media.

Materials and Methods

The experiment was conducted at the University of Flori

da, Tropical Research and Education Center, Homestead,

Fla. The spent potting media (mix of ground plant and pot

ting mix) and the new media were provided by Lovell Farms

Inc., Miami, Fla., on 25 July 2000 and 31 Aug. 2000, respec

tively. Clear, 0.10-mm-thick PE film was used to make plastic

bags of 41 cm x 62 cm. The potting mix was distributed into

the PE bags to 8 cm depth, sealed with an impulse hand sealer

(Model AIE-600, American International Electric, Inc., Whit-

tier, Calif.) and solarized on benches in open air (Fig. 1). The

main treatments were spent media solarized for 0, 2 or 4

weeks and new media. Solarization started on 1 Sept. 2000. All

solarized media bags were turned over once a week as per

Kaewrung et al. (1989). Thermometers were placed at the

surface, middle, and bottom of each bag during solarization

of recycled media and temperature data were recorded at

each depth every other day between 1:00 and 3:00 PM. The

timing of soil treatment was staggered so that all treated

media could be potted at the same time.

At the end of the solarization period and before trans

planting the seedlings, electrical conductivity (EC) and pH

were determined in a 1:2 (wt/vol) medium: deionized water extract (2 h shaking).

Following solarization treatment, the potting mix from

each bag was distributed to 10-cm-diameter pots. Slow release dry fertilizer at full rate (7. 7 g/L or 0.76 m3 of media) of 13-

13-13 was added only to the new media, mixed well, and dis

tributed to similar pot size. This rate of the fertilizer used in

this experiment was similar to that used by Lovell Farms, Inc.

for the production of these three bedding plant species.

Three-week-old seedlings of each impatiens ('S.E. Blue

Pearl'), periwinkle ('Pacifica Red'), and petunia ('Ultra Rose')

were planted in each of these free-draining pots, arranged in

Proc. Fla. State Hort. Soc. 114: 2001. 259

Figure 1. Solarization of spent potting media in polyethylene plastic bags.

a completely randomized design with eight replications, and

watered daily in a shade house.

All treatments (solarized and new) were either treated

with humic acid as an organic amendment or not treated.

Humic acid ESP-50, a black powder provided by Earthgreen

Products Inc. (Dallas, TX), was added at rate of 28 g per 40

liters of water. Each pot received 25 ml of dissolved solution

following the company's specifications.

One month after transplanting, plants were drenched

with soluble fertilizer once every 2 weeks. Disease symptoms

and occurrence of dead plants were observed and recorded

during the production period.

Nine weeks after transplanting, plants were evaluated for

height, width, number of flowers, and greenness of foliage.

Variances and separations of means were analyzed using Dun

can's Multiple Range Test at the 0.05 probability level of the

Statistical Analysis System (SAS Institute, 1985).

Results and Discussion

The pH and the EC of the new media and that of recycled,

spent potting media were within the general recommenda

tions reported by Klock-Moore and Fitzpatrick (2000) on pH

(5.8 to 6.2) and EC (0.75 to 3.49 mS.cm1) for bedding plants.

The recycled spent media was examined before solariza

tion for plant parasitic nematodes at the Univ. of Florida En

tomology and Nematology Dept. laboratory in Gainesville

and results showed that there were no nematodes.

The temperature of the solarized media was higher at the

surface than in the middle and the bottom (Fig. 2). The aver

age range of solarized media temperature was 52-59.7°C at

the surface, from 42-53.8°C in the middle, and 38-45°C in the

bottom.

Impatiens. Solarization for 2 or 4 weeks increased impa-

tiens plant height, width, and dry weight in non-organically

amended treatments (P < 0.001) and in treatments amended

with humic acid (P < 0.01) compared with those grown in new

or non-solarized media (Table 1). This increase ranged from

Sept 4 Sept 8 Sept 11 Sept 15 Sept 19 Sept 22 Sept 26 Sept 30

Time

Figure 2. Temperature of recycled potting media at the surface,

and bottom of plastic bags during solarization.

middle,

2- to 2.5-fold and could be due to the release of nutritive min

erals that occurred during solarization as shown by Chen and

Katan (1980) and Grunzweig et al. (1998). These results are

in agreement with those presented by Gamliel et al. (1989)

who showed an increase in tomato seedling dry weight when

Table 1. Horticultural parameters of impatiens plants as affected by solariza

tion and organic amendments 9 weeks after transplanting.

Treatment'

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level"

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Organic amendment

No amendment Humic acid

7.87 by

11.25 a

11.12a

6.66 b

#**

7.20 b

10.50 a

11.12 a

5.97 b

##*

15.25 b

22.12 a

22.5 a

11.13b

13.00 b

21.87 a

21.37 a

12.29 b

Plant dry wt (g/plant)

1.50 b

2.20 a

2.34 a

1.17b

***

1.17b

2.06 a

2.23 a

1.43 b

**

12 b

23 a

26 a

7b

*##

T? T

8c

21 ab

22 a

12 be

LG

G

G

G

G

DG

DG

DG

Significance

level

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

'Treatment: Sol 0 wk: no solarization; Sol 2 wk: solarization for 2 weeks; Sol

4 wk: solarization for 4 weeks.

Means within same column followed by the same letters are not signifi

cantly different at P < 0.05, using Duncan's Multiple Range Test.

"Significance level: NS: no significance; **: P < 0.01% and ***: P < 0.001%.

wFoliage color description: G: Green; DG: Dark Green; and LG: Light

Green.

260 Proc. Fla. State Hort. Soc. 114: 2001.

grown in solarized, recycled container media compared with

those grown in new media. In addition, number of flowers in

creased 2-fold in solarized media treatments addition without

the addition of organic amendment, and over 2.5-fold in so

larized media treatment that received humic acid in compar

ison with those grown in non-solarized media. The addition

of humic acid did not result in significant differences among

treatments, however, it increased the foliar green color in

plants grown in any media.

Periwinkle. Periwinkle plants were the most sensitive plants

to soil-borne pathogens. All plants that were grown in non-

solarized, recycled potting media died during the first week

after transplanting due to soilborne pathogens as Fusarium

spp. and Rhizoctonia solani that were isolated from diseased

plants (Table 2).

Solarization for 2 or 4 weeks increased periwinkle plant

height, width, dry weight, and number of flowers (P < 0.001)

compared with those grown in new or non-solarized media.

The increase was doubled in solarized media irrespective of

the addition of the organic amendment. These results are in

Table 2. Horticultural parameters of periwinkle plants as affected by solar

ization and organic amendments 9 weeks after transplanting.

Treatment'

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level*

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Organic amendment

No amendment

Plant hpicrl

Humic acid

Dead c>

12.71a

12.12a

6.2 b

***

Dead d

10.25 b

12.25 a

5.56 c

***

"PI M Kit" !Af1/"1t"V* /^»W^\

Deadc

18.14 aAx

18.12 a

8.69 b

***

Plant dry wt i

Deadc

2.36 aA

2.32 a

0.69 b

***

_______ Fl/^iA/^r' n/~\ — ----- r 1UWCI I1U.

Ob

2a

2a

Ob

***

Deadd

15.00 bB

18.87 a

7.56 c

***

(g/plant)

Deadd

1.62 bB

2.48 a

0.54 c

***

/nlnnf

0d

2b

3 a

1 c

***

i

Dead

LG

G

G

Dead

G

DG

G

oignincance

level

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

NS

'Treatment: Sol 0 wk: no solarization; Sol 2 wk: solarization for 2 weeks; Sol

4 wk: solarization for 4 weeks.

>Means within same column followed by the same letters (lower case) and

"Means within same row followed by the same letters (upper case) are not

significantly different at P < 0.05, using Duncan's Multiple Range Test.

"Significance level: NS: no significance; **: P < 0.01% and ***: P < 0.001%.

"Foliage color description: G: Green; DG: Dark Green; and LG: Light

Green.

agreement with those reported by Gamliel et al. (1993) who

showed an increase in Gypsophila paniculata plant yield using

solarized container media. The increase in these horticultur

al parameters with solarized media could be attributed to the

reduction of pathogens during solarization, which has been

ascribed not only to high temperatures inside the plastic bags

but also to the production of volatiles such as carbon dioxide,

ethylene, and other substances that are toxic to fungi (Kae-

wrungetal., 1989).

Periwinkle plants grown in 2-week solarized media treated

with humic acid had lower plant width and dry weight com

pared with those grown in 2-week solarized media without hu

mic acid (P < 0.01). The reason behind this decrease is not

clear. Green foliar color of periwinkle plants was darker in

those treatments that received humic acid compared to those

without it.

Petunia. Petunia plant height and width were significantly

higher (P < 0.001) when grown in new media, followed by

those grown in solarized media or non-solarized media with

out the addition of humic acid (Table 3). However, addition

of humic acid significantly increased plant width and dry

weight in solarized media (for 2 or 4 weeks) over those grown

in non-solarized media (P < 0.001), but had no effect on those

grown in new media. The addition of humic acid has the po

tential to act as a growth regulator (Lee and Bartlett, 1976)

and the possibility to increase microbial activity in the media

(Chenetal., 1988).

Number of flowers was significantly increased with the ad

dition of humic acid to petunias grown in either new media

or media solarized for 2 or 4 weeks. The increase in plant

width, dry weight, and number of flowers in the 2- or 4-week

solarized media that were treated with humic acid could be at

tributed to the increased activity of the beneficial organisms

in the media, which could have improved plant health (Sta-

pleton and DeVay, 1984, 1986).

The addition of humic acid to any potting media provided

darker green foliage compared to those without humic acid.

Conclusions

Horticultural parameters of impatiens, periwinkle, and

petunia plants were increased in 2- and 4-week solarized me

dia compared with those grown in non-solarized media. Solar

ization without the use of the humic acid produced healthier

and bigger impatiens plants than those grown in new or non-

solarized media. Solarization for 2 or 4 weeks definitely pro

tected periwinkle plants from dying from fusarium, phytoph-

thora and rhizoctonia whereas, those grown in non-solarized

media were adversely affected by these soilborne pathogens,

which killed them within a week after transplanting. Healthi

er, more vigorous petunia plants with more flowers were at

tained when grown in 2- or 4-week solarized media amended

with humic acid. The addition of humic acid produced green

er foliage in bedding plants.

Solarization in PE plastic bags provided a fast and inex

pensive technique to disinfect spent potting media, helped in

finding an avenue for recycling the stockpiled media, and in

directly reduced media disposal into landfills.

As MB (soil fumigant) phases out in 2005 world-wide, the

solarization technique for potting media disinfection will at

tract more attention from nursery growers for utilizing and

recycling spent, disease-infected potting media for bedding

plant production. They may adopt the technique by filling

Proc. Fla. State Hort. Soc. 114: 2001. 261

Table 3. Horticultural parameters of petunia plants as affected by solariza-

tion and organic amendments 9 weeks after transplanting.

Treatment7

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance levelw

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Significance level

Sol 0 wks

Sol 2 wks

Sol 4 wks

New media

Organic amendment

No amendment

if lant neig

14.00 c>

17.25 b

16.37 b

18.81 a

#**

Humic acid

lit (rm\

13.75 b

17.62 a

18.12 a

18.37 a

#**

_ _ Plant wirltl"1 (rm\

16.50 c

19.12 bBx

18.87 bB

25.25 a

***

Plant dry wt

1.79 b

2.40 bB

2.45 bB

3.99 aB

***

_______ 171/"viaj^v* n o ------- J7HJVVC1 IIU

5b

7abB

7abB

8aB

NS

—> — — — — — 17f\ 11 Q fTA* t — -------pUJ.ld.gC (,

LG

LG

G

G

16.94 b

23.75 aA

24.37 aA

24.75 a

***

(g/plant)

1.93 b

4.57 aA

4.55 aA

5.21 aA

***

/ r\\ ant--- --./ JJLd.Hl - - - — - -

5b

llaA

10 aA

11 aA

***

Tilr»ru - - - - _ _ _ _UlvJl ---- — ---

G

DG

DG

DG

• Significance

level

NS

NS

NS

NS

NS

#**

***

NS

NS

##*

***

*

NS

***

'Treatment: Sol 0 wk: no solarization; Sol 2 wk: solarization for 2 weeks; Sol

4 wk: solarization for 4 weeks.

>Means within same column followed by the same letters (lower case) and

"Means within same row followed by the same letters (upper case) are not

significantly different at P < 0.05, using Duncan's Multiple Range Test.

"Significance level: NS: no significance; *: P < 0.05%; **: P < 0.01% and ***:

P< 0.001%.

"Foliage color description: G: Green; DG: Dark Green; and LG: Light

Green.

the pots with the media, covering the pots tightly with PE plas

tic sheeting, solarizing the potted media for a period between

2 to 4 weeks, and then growing the bedding plants in the so

larized potted media. Also, the approach we followed here for

solarization of potting media in plastic bags has another di

mension that can be very useful for homeowners. They may

solarize the media in plastic bags and plant the bedding

plants in the solarized media. This approach will aid them

easily and quickly moving the planted bags around in their

gardens for landscaping purposes.

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ting media for ornamental plants. Soil Sci. 145:298-303.

Chen, Y. and J. Katan. 1980. Effect of solar heating of soils by transparent

polyethylene mulching on their chemical properties. Soil Sci. 130:271-

277.

Gamliel, A., E. Hadar, and J. Katan. 1993. Improvement of growth and yield

of Gypsophila paniculata by solarization or fumigation of soil or container

medium in continuous cropping systems. Plant Dis. 77:933-938.

Gamliel, A. andj. Katan. 1991. Involvement of fluorescent pseudomonads

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Gamliel, A., J. Katan, Y. Chen, and A. Grinstein. 1989. Solarization for the re

cycling of container media. Acta Hort. 255:181-188.

Gamliel, A. andJ.J. Stapleton. 1993. Effect of soil amendment with chicken

compost or ammonium phosphate and solarization on pathogen control,

rhizosphere microorganisms and lettuce growth. Plant Dis. 77:886-891.

GrunzweigJ. M.J. Katan, Y. BenTal, and H. D. Rabinowitch. 1998. The role

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in solarized soil. Plant and Soil 206:21-27.

Kaewruang, W., K. Sivasithamparam, and G. E. Hardy. 1989. Effect of solar

ization of soil within plastic bags on root rot of gerbera (Gerbera jamesonii

L.) Plant and Soil 120:303-306.

Kamra, A. and H. S. Gaur. 1995. Control of plant parasitic nematodes by so

larization of soil polyethylene bags. Ann. Plant Prot. Sci. 3:90-92.

Katan, J. 1987. Soil solarization, p. 77-105. In: I. Chet (Ed.). Innovative Ap

proaches to Plant Disease Control. Wiley, New York.

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