Mycorrhizae in a Wastewater-irrigated

8/11/2019 Mycorrhizae in a Wastewater-irrigated

1/10

Plant and Soil 121, 187-196 (1990).

~) Kluwer Academic Publishers. Printed in the Netherlands'. PLSO 8243

Vesicular-arbuscular mycorrhizae in a wastewater-irrigated oldfield

ecosystem in Michigan

G .R. S A FIR , J .O . SIQ U EI RA ~ an d T .M. BU RT O N

Department o f Botany and Plant Pathology and the Department o f Zoology Michigan State University

East Lansing M I 48824 USA . IOn sabbatical leave.from ES A L Lavras -MG Brazil

Received 16 May 1989. Revised Augus t 1989

Key words: Glomu s, i rrigat ion, mycorrhizal fungi, soi l microorganisms, wastew ater disposal

bstract

The incidence of vesicular-arbuscular mycorrhizae (VAM ) in wastewater i rrigated and non-irrigated

oldfield soils in Michigan was studied. Soil and root samples were taken monthly from field plots on the

second and third years o f consecutive irrigation w ith municipal wastew ater at rates of 0, 5 and 10 cm wk J.

The oldfield ecosystem contained a high V AM fungal spore pop ulat ion density, but low species diversity.

The most co mm on V AM fungal species were

Glomus mosseae

and

G. fasciculatum.

Both spore density and

roo t coloniza tion were higher in irrigated than in non-irrigated plots. Irrigation effects were largest early in

the growing season. In addit ion to increasing VAM incidence, wastewater i rrigat ion shifted VAM fungal

species composit ion. Irrigat ion favored G. mosseae over G. fasciculatum. Bioassays using either Sorghum

vulgate

o r

Daucus carota

an oldfield native species, indicated that the VAM systems were still functioning

after the third year o f consecutive wastewater i rrigat ion. The da ta f rom experiments using nutrient solutions

at was tewater concentrat ions suggest that the effects of wastewater i rrigation on VA M are due to the effects

of both water and nutrients. Since VA M are a very importan t com ponen t of the plant s w ater and nutrient

uptake system and equally importan t in structuring plant com munit ies under l imit ing growth condit ions, i t

is suggested that the st imulatory effect of wastewater i rrigat ion on VA M in an oldfield ecosystem enhances

the ecos ystem s ability to fun ction as a living filter for w astew ater clean up.

Introduction

Soil and its vegetation act as a wastewater filter

and can provide a desirable al ternative for disposal

of secondary treated wastewater (Bower and

Chaney, 1974). Applicat ion of was tew ater to ei ther

natural or agricultural eco systems often increases

plant biomass production (see overview by Brock-

way

et al.

and other individual papers in D Itri ,

1982). Howev er, this increased biom ass prod uction

has to be balanced against possible contamination

of aquatic and groundwater systems, especial ly

with ni trate and chloride (Burton, 1978; Burton

and King, 1981), possible problems with increased

Michigan Agricultural Experimental Station Journal Article

No 13137.

187

spread of human pathogens (Kowal et al. 1981;

Kristensen and Bonde , 197 7; Shuval, 1977), and

possible deleterious effects on the plant com-

munities within natural e cosystem s including

changes in species comp osit ion (Burton a nd H ook ,

1982) and injury and vegetation decline if

wastewater is applied in excess (Burton, 1982).

Other adverse effects of wastewater applicat ion on

vegetat ion may result from over fert il izat ion (Baier

and F ryer, 1973; Nea ry et al. 1975), increased

disease incidence (Epstein and Safir, 1982 ) and

depression of biological nitrogen fixation in

legumes (Tesar et al. 1982). Despite these pote ntial

problems, reuse of wastewater is a widespread

pheno men on worldwide (Heaton, 1981) and offers

substantial advantages o ver discharge into aquatic

ecosystems, especially in low precipitation areas of


2/10

188 Safir et al.

the world . An a rea of concern to us tha t has been

la rge ly over looked i s the potent ia l impac t of

was tewate r nut r ients , toxins , pa thogens and ant i -

mic robia l agents , such as chlor ine , on the des i rable

mic robiologica l processes in the so i l ecosys tems. Of

par t icula r in te res t i s the impac t on ves icula r-

a rbusc u l a r myc or rh i z a e (VAM).

VA M a re wi del y r ec ogn i z e d as c omp one n t s o f a ll

t e r res t r ia l ecosys tems (Saf i r , 1987) , and known to

be essentia l to above- (Allen and Allen, 1984) and

be low-ground processes in o ldf ie ld ecosys tems

(Crowel l and Boerner , 1988) . S ince VA M for-

mat ion and func t ion a re sens i t ive to so i l mois ture

(Nelso n, 1987) and fert i l i ty (H ay ma n, 1982), the

e ffect of was tewate r i r r iga t ion on na tura l ly occur-

ing VA M is of in teres t . In th i s paper , we repor t the

e ffec t s of three consecut ive yea rs of was tewate r

i r r iga t ion on the incidence of VAM fungi and

VA M infec t iv i ty in an o ldf ield ecosys tem in

Michigan.

aterial and methods

Field studies

Thi s s t udy wa s c onduc t e d a t t he wa t e r qua l i t y

man agem ent fac i l i ty a t Michiga n S ta te Univers i ty ,

on a n a ba ndo ne d fa rm f i el d s it e t ha t ha d no t be e n

cul t iva ted for approximate ly 10 yea rs . S i te veg-

e t a t ion wa s dom i na t e d b y a mi x t u re o f qua c kgra s s

Agropyron repens) a nd go l de n rod Solidago

graminifolia a nd Solidago canadensis) with a

diverse mixture of other oldfie ld species. This fie ld

was divided into 24 x 27 m plots that received 0, 5,

a nd 10 c m wk - 1 o f c h l o r i na t e d mun i c i pa l

Table 1. Mean annual conc entration (mg L -~) of w astewater

applied to the oldfield site (from Hook and Burton , 1978)

Constituent Second year Third year

Nitrate -nitrogen 10.5 9.1

Ammonium-nitrogen 1.4 1.2

Total nitrogen 13.7 13.6

Total phosphorus 2.7 2.7

Potassium 10.0 10.5

Calcium 69.9 57.9

Magnesium 24.4 25.6

Sodium 86.5 97.1

Chloride I 12.0 120.0

pH = 7.5; alkalinity - equivalent

CaC O 3 =

150.

Table 2.

Average soil analyses/~g g d ry so il ~, for the top 30 cm

of soil of the oldfieldsite after two years of w astewater irrigation

(after Hook and Burton, 1978)

Constituent 0 cm wk -t 5 cm wk -~ 10 cm wk -~

Phosphorus (Bray) 18.1 11.0 17.5

Potassium (NH 4OA c) 135.8 75.1 73.6

Calcium (NH4O Ac) 806.8 932.4 944.8

Magnesium (NH4OA c) 89.3 130.6 160.4

Sodium (NH4OAc) 27.9 87.0 99.7

Chloride

K2 SO4)

9.6 32.2 32.7

NO3-nitrogen 1.3 1.9 2.3

(Kjeldahl)

was tewate r i r r iga t ion by spray . The was tewate r

or ig ina ted f rom the Eas t Lans ing, Michigan sewage

t rea tme nt fac i li ty f rom the f i rst of four lakes used to

s tore th i s was tewate r pr ior to i r r iga t ion (see Table

1 for chemica l ana lys i s of th i s was tewate r) . Spray

i r r i ga t i on c on t i nue d f rom Apr i l t o Oc t obe r e a c h

year.

Soi l chemis t ry for these p lo t s de te rmined a f te r

the f i rs t and second yea rs of i r r iga t ion , indica ted

tha t was tewate r i r r iga t ion inc reased ca lc ium, mag-

nes ium, sodium, and chlor ide in these so i l s (Table

2) . Mass ba lance budge ts f or the s i te a l so indica ted

tha t subs tant ia l am oun ts of N an d P were be ing

re ta ined by the vege ta t ion and soi l s (Burton and

Hook, 1982; Hook and Burton , 1978) .

Prec ip i ta t ion averaged 77c m year -~ wi th an

a ve ra ge snowfa l l o f 124c m ye a r -~ . Te mpe ra t u re

a ve ra ge d 8 .2 C wi t h a me a n mon t h l y l ow o f

- 5 . 5 C i n J a n u a r y a n d a m e a n m o n t h l y h i g h o f

27.6C in Ju ly . The average grow ing season in th is

pa r t o f Mi c h i ga n e x t e nds f rom Ma y 7 t o Oc t obe r 8

(154 days).

To eva lua te VAM inc idence , 20 so i l and root

s a mpl e s we re r e move d mon t h l y f rom Ma y t o

Oc t obe r , fo r a t wo ye a r pe r i od f rom e a c h o f si x

rand om ly ass igned 24 x 27 m plo ts tha t rece ived

0, 5 o r 10 cm wk - a of w as tewate r . Was tewate r i r -

r iga t ion had been appl ied in the yea r be fore sam-

pl ing and was appl ied a t the same ra te dur ing the

two years of sampl ing . They a re re fe rred to a s the

second and th i rd yea rs of consecut ive was tewate r

i r r iga t ion . P lo ts were not h a rves ted dur in g the sam-

pl ing pe r iod . Samples were taken to a depth of

25c m a nd 5c m se c t i ons we re s e pa ra t e d a nd

a na l yz e d fo r VAM spore numbe rs . F i f t e e n g ra m

samples f rom each 5 cm sec t ion were thoro ugh ly

mixed in 100 mL of d i s t il l ed wa te r and we t -s ieved

t h rough 40 a nd 325 -me sh s c re e ns (Ge rd e ma nn a nd


3/10

VA mycorrhizae in a waste-water irrigated oldfield 189

Nicolson, 1963) and the spores separated by

sucrose (density = 1.18gcm 3) centrifugation.

Spores were grouped by appearance and counted

under a dissecting microscope. These groups were

later classified to the species level as described in

Gerdemann and Trappe (1974) and Trappe (1977).

In the third year of consecutive application, root

samples were taken from 20 plants, separated by

species, in three 2 2m random sections from

each plot. Quackgrass

Agropyron repens)

the

predominant species, was sampled on a monthly

basis, while other species were sampled only in

September. Roots were separated from soil,

washed, cleared, and stained according to Phillips

and Hayman (1970). For colonization assessment

stained segments were mounted on microscope

slides, scanned for VAM fungal structures, and

rated as 3, 2 and 1 according to the intensity of

fungal structures in the root as follows. Rating 3

when fungal structures were present in at least

130 mm/200 mm of root; 2 if they were present in

60-129mm/200mm and 1 if present in 1-59mm/

200 mm of root. The data were subjected to a one

way ANOVA and the means for each sampling

time separated by the Student-Newman-Keuls'

multiple range test at the 0.05 level.

Greenhouse experiments

To evaluate the effects of wastewater application

on VAM infectivity and effectiveness of oldfield

ecosystems, VAM formation potential and effects

on plant growth were assessed using sorghum

Sorghum vulgare) (routinely used for infection

studies) and Queen Anne's lace Daucus carota), a

mycorrhizal oldfield species, as test plants. Both o f

these species are easily produced from seeds.

Quackgrass was not used for these studies because

of the difficulty n obtaining uniform plant material

for propagation. The first experiment was conduc-

ted for 10 weeks in waxed cups containing 800 g of

soil collected from each irrigation treatment (0, 5

and 10cmwk-I), by the end of the third consecu-

tive year of irrigation. In addition soil from the

highest irrigation level (10cmwk -t ) and a sandy

loam soil (with pH = 7.7 and 8 ppm of P) were

autoclaved and included as treatments. Each treat-

ment had 8 replications. In the second experiment,

sorghum remained untreated or was inoculated

with VAM fungi and planted in either 10 cm wk -I

irrigated or greenhouse autoclaved soil. Highly in-

fective VAM fungus inoculum (a mixture of

Glomus mosseae and Glomus asciculatum) originat-

ing from sudangrass greenhouse pot cultures, was

applied at a rate of 200 g of soil inoculum per 800 g

of either field or greenhouse soil. Each treatment

had 6 replications and the experiment was conduc-

ted for 10 weeks. A third set of experiments was

conducted using the same treatments as the second

experiment, except that the oldfield native plant

Queen Anne's lace

D. carota)

was used as a test

plant. At the end of each experiment plants were

harvested and shoot dry weights were determined.

Roots were separated from the soil for assessment

of VAM colonization as previously described.

In additional greenhouse experiments, nutrient

solutions were adjusted to simulate wastewater (ac-

cording to Table 1) using the following salts:

(NH4)2NO3, KNO3, NaH2PO4, NaC1, CaC12

2H20, Ca(NO3) '4H20, MgSO4 7H20, CaSO4,

CaCO3, MnSO4.4H2 and FeSOa'7H20. Pre-

germinated seeds of

D. carota

were planted in

waxed cups containing 800 g of oldfield soil, to

which the following treatments were applied: 1)

water-stressed control (100mL of distilled water);

2) water irrigated (190mL of distilled water); 3)

simulated wastewater (100 mL of nutrient solution)

and; 4) water and nutrient (190mL of nutrient

solution). These treatments were applied in the pres-

ence and absence of VAM inoculum

G. mosseae

and

G. fasciculatum)

as previously described.

Simulation treatments had 8 replications and were

applied 5 times per week to approximate the 5 cm

irrigation rates. After 12 weeks growth, plants were

harvested and dry weight and root colonization

assessed as previously described. Every experiment

was repeated once. All the data were subjected to

statistical analysis and significant effects separated

by the Student Newman-Keuls multiple range test

at the .05 probability level.

esults

Incidence of VAM

The oldfield site from Michigan had spore

population densities as high as 25 spores/g soil

(Table 3, 4). The predominant fungal species


4/10

190

Safir

et al.

Table 3

Effect of waste water irrigati on on soil spore density for the three predo min ant VAM fungal species in a oldfield ec osystem

in Michigan. Data (number of spores/15 g soil) for the second consecutive year of irrigation in the 0- -1 0c m top soil layer

Sampling G fasc icu latum G mosseae G constr ic tum

time

0 5 cm wk -~ 10 cm wk ~ 0 5 cm wk -~ 10 cm wk -t 0 5 cm wk -~ 10 cm wk -~

Ma y 109 be 331 a 392 a 41 cd 154 b 111 b 29 d 84 c 57 cd

June 134 b 203 ab 282 a 49 cd 188 ab 170 ab 47 c 22 c 38 c

July 167 b 161 b 417 a 53 cd 127 b 411 a 43 b 21b 54 b

August 132 c 169 b 163 b 60 cd 170 b 282 a 40 cd 47 cd 50 cd

Septemb er 98 cde 160 bcd 207 b 105 ode 270 b 353 a 56 de 32 de 58 de

October 107 c 151 b 164 b 66 cd 223 a 281 a 57 cd 57 cd 55 cd

Means in the same line (month) followed by the same letters are not statistically different by the Student-N ewman-Keuls multiple range

test at .05 level.

Table 4 Effect of wastewa ter irrigation on soil spore density for the three predo min ant VAM fungal species in an oldfield e cosystem

in Michigan. Data (number of spores/15 g soil) for the third year o f consecutive irrigation in the 0- -1 0 cm t op soil layer

Sampling

G fasc ic ula tum G mosse ae G c ons t ri c tum

time

0 5 cm wk t 10 cm wk -t 0 5 cm wk -~ 10 cm wk -~ 0 5 cm wk -~ i0 cm wk t

May 31 b 33 b 18 c 22 c 81 a 28 b 2 d 5 d 10 d

June 13c 44a 23b 7c 75a 29b 4c 4c 7c

Jyl y 8 c 19 b 15 b 8 c 35 a 23 a 6 c 2 c 4 c

August 17 c 34 a 20 bc 14 c 38 a 17 c 6 c 18 c 7 d

September 19 c 30 b 20 d 22 cd 60 a 28 bc 6 f 16 de 11 e

October 11 c 28 a 20 a 10 c 87 a 23 a 2 d 12 b 6 c

Means in the same line (month ) followed by the same letters are not statistically different by the Stude nt-Newman-Ke uls multiple range

test at .05 level.

recovered were identified as

Glomus mosseae

Glomus fasc iculatum

and

Glomus constric tum. A

fourth species

Sclerocyst is rubiformis

was found in

low numbers and for th is reason was not con-

s idered fur ther . Spore nu mbers were higher in the

second Table 3) than in the th ird year of consecu-

tive wastew ater irrigation Table 4), even in non-

irrigated plots .

In the second year of consecut ive i r r igat ion

Table 3) , the numbers of

G. mosseae

and G.

fasc iculatum

spores were higher in i r r igated than in

non- ir r igated plots .

G. constric tum

was only sig-

nif icant ly af fected by i r r igat ion in May of the

second year . In non- ir r igated plots ,

G. fasciculatu m

had higher spore numbers in June and July , while

in i r r igated plots , a t bo th 5 and 10 cm wk -t , spore

numbe rs were higher ear l ier in the growing season

and decreased toward the end o f the season. G.

mosseae

d id no t change th ro ughou t the s eason in

non- ir r igated plots , but increased la te in the season

in irrigated plots .

G. constric tum

had a lower spore

dens i ty than the other VAM fungus species and

was less affected by either sampling time or irri-

gat ion t reatment .

In the th ird year of consecut ive i r r igat ion Table

4), 5 cm wk - ~p lo ts had m ore o f

G. mosseae

and G.

fasc iculatum spores than the 10c mw k -~ plots a t

most sampling t imes . G. constric tum spore numbers

were s ignif icant ly dif ferent in Au gust and Septem-

ber whe n 5 cm wk -~ plots had more spores tha n

ei ther non- ir r igated or 10 cm wk-~ t reatments .

Despi te the monthly var ia t ion, i r r igated plots

had h igher num bers o f

G. mosseae

and G.

fasc iculatum

populat ion dens i t ies than non-

ir r igated ones for both

G. mosseae

and G.

fasc iculatum

dur ing both sampling years but to a

lesser extent in the third yea r Fig. 1).

G. constric-

turn

however responded very l i t t le to i r r igat ion.

Spore numbers were also affected by soil depth.

Spores were concentrated in the upper 15 cm o f soi l

and their distribution in the soil profile was dif-

ferent ial ly af fected by i r r igat ion an d sampling t ime

Figure 2). In Ma y, i r r igated plots had an average

of 4 .6 t imes more spores th an non- ir r igated ones in


5/10

VA mycorrhizae in a waste-water irrigated oldfield 191

4 0 0

0 G f s c i c u l t u m

6 oo

0 )

tO

iI~ 2OO

1o

0 5 10

G. m o s s e e

0 5 10

I ] Second year

[]

Third year

G. c o n s r r i c t u m

o 5 lO

I r r i g a t i on T r e a t m e n t s c m / w k

Fig. 1.

Overal l e ffec ts of wastew ater i r r iga t io n levels on the sp ore

de ns i t i e s of

G. fascicu latum, G. mosseae

a n d

G. constrictum

in a n

oldf ie ld so i l dur in g the s e c ond a nd th i rd ye a r s of c onse c ut ive

irr iga t ion.

5.0

o

t~ 4.0

I f :

E

~ 3.0

Z

ca

~ 2.0

September

,~/

, h , L 115 0 ,

5 10 2 25

S o i l Dep t h cm

Fig. 2.

Effe ct of wa s te wa te r i r riga t ion on V AM spore de ns i ty a t

inc re a s ing so i l de pth a t the be ginning a nd a t the e nd of the

g r o w i n g s e a s o n d u r i n g t h e s e c o n d y e a r o f c o n s e c u t i v e

wa s te wa te r a ppl ic a t ion . Each data point r e pre se nt s the r a t io of

m e a n spore de ns i ty for i r r iga ted 5 a nd 10 c m w k - t p lo t s ) ove r

non- i r r iga te d p lo t s .

the 0-5 cm soil layer. This rat io dropped to less

than 2.0 at higher depth 20-25 cm). By September

this trend reversed, i .e . irrigation favored fungal

spore production at deeper layers in the profile.

In addition to effects on total spore number,

irrigation altered VAM fungal community struc-

ture in the oldfield soil Fig. 3). The calculated ratio

between numbers of G. mosseae/G fascicula tum

spores indicated very little effect of sampling time

O

=

t 2

8

c

May

a irrigated -0 - Non-irrigated

qr i ..Q I O O 8

Second Year Third Year

I i I I J L I I I I I

J u l Sept May Jul Sept

S a m p l i n g T i m e

Fig. 3.

R a t i o o f m e a n s p o r e n u m b e r s f o r

G. mosseae

M O S )

ve r sus

G.fasciculatum

FAS) in i r r igate d a nd n on- i r r iga te d p lo t s

t h r o u g h o u t t h e g r o w i n g s e a s o n i n t h e s ec o n d a n d t h i rd y e a r o f

c onse c ut ive wa s te wa te r i r r iga t ion .

in non-irrigated plots, but a considerable effect in

irrigated plots. In the second year of wastewater

application, the G. mosseae/G fasciculatum spore

number ratio increased from 0.36 early in the

season May) to 2.0-2.5, late in the season Septem-

ber and October). In the third year, however, this

ratio was not as high as was found in the second

year, but was much less affected by the sampling

time.

Since plant species composition differs in ir-

rigated and non-irrigated plots, individual species

can not be compared, except for quackgrass, which

3.0

ca

t-

e -

i-

._o

C

2

O

tJ

2.5

2 0

1 5

1 . 0

o . o f

A I r r i g a t e d , ~

- - - 0 - - - N o n - i r r i g a t e d / /

/ /

/ / /

I I

May June July

S a m p l i n g T i m e

Au;ust I

September

Fig. 4. V A M r o o t c o l o n i z at i o n r a t i n g o f q u a c k g r a s s Agropyron

repens)

a f te r the th i rd ye a r o f c onse c ut ive wa s te wa te r i r r iga t ion

a nd f rom non- i r r iga te d p lo t s in a n o ldfie ld e c osys te m dur ing the

growing se a son.


6/10

192

Safir

et al.

was present in both situations. The overall species

root colonization means for non-irrigated and ir-

rig ate d plots we re 1.6 + 0.4 and 2.5 +__ 6, respec -

tively. T he m onthly colonization rating, for qu ack-

grass from non-irrigated and irrigated plots are

given in Figu re 4. Irrigated plots were mo re heavily

colonized from May to July, but no differences

were evident late in the growing season. Althou gh

non-irrigated plots reached the same colonization

levels as irrigated ones late in the season, higher

VAM formation earlier in the season may be of

great advantage for plant nutrient uptake and

growth.

Effects on V A M formation and funct ion

The greenhouse assays using sorghum

demonstrated that three years of consecutive

wastewater irrigation had no significant effect on

either VAM formation or plant growth (Table 5).

However, when 10c mw k -~ irrigated soil was

autoclaved to eliminate VAM propagules, plant

growth was significantly reduced. Re-infestation of

the same soil with mixed VAM inoculum, restored

its infectivity and greatly increased sorghum and D.

carota growth. This suggests that wastewater ir-

rigation for three consecutive years at rates as high

as 10c mw k -~ had no adverse effects on VAM

formation and function.

Simulation experiments using

D carota

showed

significant plant growth responses (Figure 5). R oot

colonization was at the same level as those o f D.

carota

inoculated plants in E xperiment 3 (Table 5)

and was no t affected by any of the treatments. Plant

dry weight was lower when nutrients alone (N UT )

were applied in the absence of VAM, but was im-

proved by joint application of nutrients and water

(DW + NUT). VAM fungus inocula tion im-

proved plant growth in comparison to non-m ycorr-

hizal plants in every treatment. Its effects were

more pronounced when either distilled water

(DW), nutr ien ts (NUT) or both (DW + NUT)

were applied. Plant grow th in these treatments was

equally high and significantly greater tha n every

non-inoculated treatment. Simulated wastewater

(DW + NUT) improved p lant growth in com-

parison to the control (CON) plants whether they

Table 5.

I n f e c t i v i t y a n d p l a n t g r o w t h p r o m o t i o n o f w a s t e w a t e r - i r r i g a t e d a n d n o n - i r r i g a t e d o l d f i e l d s o i l s f r o m M i c h i g a n u n d e r

g r e e n h o u s e c o n d i t i o n s

S o il o r i g in T r e a t m e n t P l a n t d r y w t R o o t

c oloniz a t ion

Experiment t - sorghum -

Non-irr iga ted f ie ld soi l

5 cm wk -~ ir r iga ted f ie ld soi l

10 cm w k -~ ir r iga ted f ie ld soi l

10 cm wk- t i r r iga ted f ie ld soi l

G r e e n h o u s e V A M c o n d u c t i v e s o i l

Experiment 2- sorghum -

10 cm wk - t i r r iga ted f ie ld soi l

10 cm wk -1 ir r ig a ted f ie ld soi l

G r e e n h o u s e s o il

G r e e n h o u s e s o i l

Experiment 3 - Daucus carota -

10 cm wk -I i r r iga ted f ie ld soi l

10 cm wk- i i r r iga ted f ie ld soi l

10 cm wk -1 ir r iga ted f ie ld soi l

G r e e n h o u s e

No ne 7.0 a b 1.6 a b

No ne 6.6 a 1.2 a

No ne 6.5 a 1.7 a

Auto c la ve d 4 .0 b 0 .0 b


Au tocl ave d 5.1 b 0.0 b

VA M inocu la ted a 10.5 a 1.8 a


VA M inoc ula te d a 11 .9 a 2 .0 a

No ne 0.87 b 1.5 a

Autoc la ve d 0 .45 c 0 .0 c

Aut ocla ved an d 1.33 a 1.0 b

V A M i n o c u l a t e d a

Autoc la ve d a nd 1 .05 b 1 .0 b

V A M i n o c u l a t e d

a Inoc ula te d w i th h ighly infe c t ive so i l inoc u lum f rom po t c u l ture c onta in in g a m ixtu re of Glomus mosseae a n d Glomusfasciculatum.

b Me a ns fo l lowe d by the s a m e le t t er s a re not s t a t i s ti c a l ly d i f f e re n t w i th in e xpe r im e nts by the S tude n t -Ke uls ' m ul t ip le r a nge t e s t a t . 05

level.


7/10


8/10

194

Saf ir

et al.

numbers for the predominate species. Irrigat ion

favored

G. mosseae

over

G. fasc i cu la tum.

After

September of the second year of consecutive irri-

gation the relative density of

G. mosseae

was twice

as high as that of


This trend con-

t inued during the third year, however, the numbers

of spores were reduced. Populat ion shifts between

these two fungi have been reported to occur in

other systems (Visser et al. 1984; W acker , 1988),

and is probably due to changes in the edaphic

environment. Hayman and Mosse (1979) reported

that l ime and phosphate amendments induced a

greater reduction in the populat ion of indigenous

fungi than of introduced G. mosseae and G.

f a s c i c u l a t u m in grassland soils in Wales. VAM

fungi do not exhibit habitat specificity, but may

have a narrow range of tolerance to environmental

conditions. G. mosseae is well known for its prefer-

ence for neutral to alkaline soils (Siqueira

et al.

1984), while

G. fasc i cu la tum

seems to tolerate a

broad er pH range. In fact, ei ther l ime or Ca 2

applicat ion has been shown to increase root

colonization by G. mosseae (Hepper and O shea ,

1984; Siqueira et al. 1984). Wastewater has a high

pH and base content and i ts applicat ion to the

oldfield ecosy stem increases Ca 2 an d Mg 2 levels

in the soil (Table 2), thus favoring G. mosseae over


Greenhouse experiments indicated that both ir-

rigated an d no n-irrigated field soils were very infec-

t ive and had an effective VA M native populat ion,

because plant growth dropped significantly when

VAM was el iminated by autoclaving soil . Growth

prom otion effects were restored b y the reinfestat ion

of autoclaved soil with a mixed inoculum of G.

mosseae and G. fasc i cu la tum. This suggests that

after three years of consecutive wastewater i rri-

gation no anti-VAM fungal factor had buil t up in

the soil and that the native VAM fungi were func-

tioning. It also suggests that application of

chlorinated wastew ater by spray irrigat ion does not

lead to reduction in VAM populat ions, due to

chlorination effects. Although

D. caro ta

is not the

predominant species in our oldfield irrigated plots,

the fact that i t showed a high degree of mycorrhizal

dependency indicates the importance of VA M in

this system. The experiment with simulated

wastewater suggests that the wastewa ter i rrigat ion

effects on VA M formation as reported here, and

biomass product ion (Burton and Hoo k, 1982) are

due to both nutrients and the water supply. The

3.5-fold increase in D. carota growth due to

inoculat ion with G. rnosseae and G. fasc i cu la tum

when water and nutrients were applied (Fig. 5), is

evidence of the importance of VAM in oldfield

irrigated ecosystems.

Urban and industrial disposal on land has been

of majo r concern among environm ental ists because

of their potential to harm the ecosystem. For in-

stance, the percent of VAM colonization in barley

was reduced by 6-fold due to land sludge appli-

cat ion (Boyle and Paul , 1988). Because formation

and function o f VAM are greatly affected by soil

nutrient status, especially P and N availability

(Hayman, 198 2), and because considerab le

amounts of these nutrients were applied in the

wastewater, between 150-270 kg ha- ~y r - 1 of N and

30-7 0kg ha - l y r - l o f P (Burton and Hoo k, 1982),

i t was expected that wastewater i rrigat ion would

reduce VAM in the oldfield ecosystem. Instead, it

favored root colonization and increased VAM

spore popula t ion densities in the top soil layer and

also deeper in the soil profile. S uch effects were also

found in a 50 year old beech-maple stand in north-

western Michigan with effluent irrigation up to

7.6 cm wk-~ (O tto, 1980). Below-gr ound activity, is

of importance to any system acting potential ly as a

living filter fo r wastew ater disposal. Since VAM are

crucial comp onents of such a system in terms o f i ts

nutrient and water uptake capacity, and equally

important in structuring plant communit ies under

l imit ing condit ions for ad equate growth (Allen and

Allen, 1984), the st imulatory act ion o f wastewater

on V AM in oldfield ecosystems ma y enhance the

efficiency of these sites as living filters for

wastewater clean up. This suggests a need for ad-

ditional long term studies.

cknowledgments

Here we would l ike to thank Ms Barbara Car-

penter for technical assistance on this project, and

CNPq-Brazil for the scholarship to J O S.

References

Allen E B and Allen M F 1984 Competiti on between plants of

different successional stages: Mycor rhizae as regulators Can


9/10

V A m y c o r r h i z a e i n a w a s t e - w a t e r i r r i g a t e d o l d f i el d 195

J. Bot. 62, 2625-2629.

Anderson R C, Libert A E, Dickman L A and Ka tz A J 1983

Spatial variation in vesicular-arbuscular mycorrhiza spore

density. Bull. Torrey Bot. Club 110, 519-524.

Baier D C and Fryer W B 1973 Undesirable plant response with

sewage irrigation. Irr. Drain. Div. Am. Soc. Civil Eng. 99,

133-141.

Bower H and Chaney R L 1974 Land treatmen t of wastewater.

Adv. Agron. 26, 133-176.

Boyle M and Paul E A 1988 Vesicular-arbuscular mycorrh izal

associations with barley on sewage-amended plots. Soil Biol.

Biochem. 20, 945-948.

Burton T M (Ed.) 1978 The Felton-Herron Creek: Mill Creek

Pilot Watershed Studies. EPA-905/9-78--002. U.S. Environ-

mental Protection Agency, Great Lakes National Program

Office, Chicago, IL, 214 p.

Burton T M 1982 Studies of land applicati on in old growth

forests in southern Michigan. In Land Treatment of

Municipal Wastewater: Vegetation Selection and Manage-

ment. Ed. F M D Itr i. pp 181-193. Ann Ar bor Sci. Publishers

Inc., Ann Arbor, MI.

Burton T M and Hook J E 1982 Oldfield and grass management

studies on the water quality management facility at Michigan

State University. In Land Treatment of Municipal

Wastewater: Vegetation Selection and Management. Ed. F M

D ltri. pp 107-133. Ann Arbo r Sci. Publishers, Inc., Ann

Arbor, MI.

Burton T M and King D L 1981 The Michigan State University

water quality management facility - A lake-land system to

recycle wastewater. In Municipal Wastewater in Agriculture.

Eds. F M D Itri, J A Martinez and M A Lambarri. pp

249-269. Academic Press, New York.

Crowell H F and Boerner R E F 1988 Influences of mycorrhizae

and phosphorus on belowground competition between two

oldfield annuals. Environ. Exp. Bot. 28, 381-392.

Dickman L A, Liber ta A E and Anderson R C 1983 Ecological

interaction of little bluestem and vesicular-arbuscular

mycorrhizal fungi. Can. J. Bot. 62, 2272-2277.

D Itri F M (Ed.) 1982 Land Treatment of Municipal

Wastewater: Vegetation Selection and Management. Ann

Arbor Sci. Publishers Inc., Ann Arbor, MI, 218 p.

Epstein L and Safir G R 1982 Plant diseases associated with

municipal wastewater irrigation. In Land Treatment of

Municipal Wastewater: Vegetation Selection and Manage-

ment. Ed. F M D Itri. pp 195-203. Ann Arbor Sci. Publishers

Inc., Ann Arbor, MI.

Gerdemann J W and Nicolson T H 1963 Spores of mycorrhizal

Endogone species extracted from soil by wet-sieving and

decanting. Trans. Brit. Mycol. Soc. 46, 235-244.

Gerdemann J W and Trappe J M 1974 Endogonaceae in the

pacific northwest. Mycologia Mem. 5, 1-76.

Hayman D S 1982 Influence of soils and fertility on activity and

survival of vesicular-arbuscular mycorrhiza l fungi.

Phytopathol. 72, 1119-1125.

Hayman D S 1970 Endogone spore numbers in soil and VAM

in wheat as influenced by season and soil treatment. Trans.

Brit. Mycol. Soc. 54, 53-63.

Hayman D S and Mosse B 1979 Improved growth o f white

clover in hill grasslands by mycorrhizal inoculation. Ann.

Appl. Biol. 93, 141-148.

Heaton R D 1981 Worldwide aspects of municipal reclamation

and reuse. In Municipal Wastewater in Agriculture. Eds. F M

D Itri, J A Martinez and M A Lambarri. pp 43-74. Academic

Press, New York.

Hepper C M a nd O Sheia J 1984 Vesicular-arbuscular mycor-

rhizal infection in lettuce

Lactuta sativa)

in relation to

calcium supply. Plant and Soil 82, 61-68.

Hook J E and Burton T M 1978 Land application of municipal

effluent on oldfields and grass lands. In The Felton-Herron

Creek: Mill Creek Pilot Watershed Studies. Ed. T M Burton.

pp 25-65. EPA-905/9-78-002. U.S . Environmental Protection

Agency, Great Lakes National Program Office, Chicago, IL.

Kowal N E, Pahren H R and Arkin E W 1981 Microbiological

health effects associated with the use of municipal wast ewater

for irrigation. In Municipal Wastewater in Agriculture. Eds.

F M D Itri, J A Martinez and M A Lambarri. pp 271-342.

Academic Press, New York.

Kristensen K K and Bonde G J 1977 The current status of

bacterial and other pathogenic organisms in municipal

wastewater and their potential health hazards with regard to

agricultural irrigation. In Wastewater Renovation and Reuse.

Ed. F M D Itri. pp 387-419. Marcel Dekker, Inc., New York.

Levi Y, Dodd J and Krikun J 1983 Effect of irrigation, water

salinity and root stock on the vertical distribution of

vesicular-arbuscular mycorrhiza in citrus roots. New Phytol.

95, 397-403.

Miller M R 1987 The ecology of vesicular-arbuscular mycor-

rhizae in the grass- and shrublands. In Ecophysiology of VA

Mycorrhizal Plants. Ed. G R Safir. pp 135-170. CRC Press

Inc., Boca Raton, FL.

Neary D G, Scheineider G and White D P 1975 Boron toxicity

in red pine following municipal wastewater irrigation. Soil

Sci. Soc. Am. Proc. 39, 981-982.

Nelson C E 1987 The water relations of vesicular-arbuscular

mycorrhizal systems.

In

Ecophysiology of VA Mycorrhizal

Plants. Ed. G R Safir. pp 71-91. CRC Press Inc., Boca Raton,

FL.

Otto P C 1980 The Effects of Sewage Effluent on Acer sp.

Mycorrhizal and Related Soil Properties. MS Thesis, Ann

Arbor, University of Michigan. 65, 164 p.

Paula M A and Siqueira J O 1987 Efeitos da umidade de solo

sobre a simbiose endomicorrizica em soja: I. Colonizacao

radicular, esporulacao, nodulacao e acumulo de nitrogenio.

R. bras. Ci. Solo 1 I, 283-287.

Phillips J M and Hayman D S 1970 Improved techniques for

clearing roots and staining parasitic and vesicular-arbuscular

mycorrhizal fungi for rapid assessment of infection. Trans.


Read D J, Koucheki H K and Hodgson J 1976 Vesicular-

arbuscular mycorrhiza in natural vegetation systems. I. The

occurrence of infection. New Phytol. 77, 641-653.

Reid C P P and Bowen G D 1979 Effects of soil moisture on V/A

mycorrhiza formation and root development in Medicago. In

The Soil-Root Interface. Eds. J L Harley and R S Russell. pp

211-219. Academic Press, London.

Safir G R (Ed.) 1987 Ecophysiology of VA mycorrhizal plants.

CRC Press Inc., Boca Raton, FL, 224 p.

Safir G R, Boyer J S and Gerdemann J W 1971 Mycorrhizal

enhancement of water tr anspo rt in soybean. Science 172,

581-583.


10/10

196

VA mycorrh i zae in a was te -water i r r iga ted o ld f i e ld

Schenck N C and Siqueira J O 1987 Ecology ofV A mycorrhizal

fungi in temperate agroecosystems. In Mycorrhizae in the

Next Decade: Practical Application and Research Priorities.

Eds. D M Sylvia, L L Hung and J M Graham. pp 2-4.

University of Florida. Gainesville.

Shuval H I 1977 Public health imp lications of wastewater reuse

for municipal purposes. In Wastewater Renovation and

Reuse. Ed. F M D Itri. pp 349-386. Marcel Dekker, Inc., New

York.

Sparling G P and Tinker P B 1978 Mycorrhiza l infections in

penn ine grassland. I. Leve l of infections in the field. J. Appl .

Ecol. 15, 943-950.

Siqueira J O Hubbell D H a nd Ma hmu d A W 1984 Effect of

liming on spore germination, germ tube growth and root

colonization by vesicular-arbuscular mycorrhizal fungi. Plant

and Soil 76, 115-124.

Tom meru p I C 1984 Effect of soil water potential on spore

germin ation of vesicular-arbuscular mycorrhizal fungi. Trans.


Tesar M B, Knezek B D and Hoo k J E 1982 Management

studies of annu al grasses and peren nial legum es and grasses at

the Michigan State University Water Quality Management

Facility. In Land Management of Municipal Wastewater :

Vegetation Selection and Managem ent. Ed. F M D Itri. pp

79-105. Ann Arbor Sci. Publishers Inc., Ann Arbor, MI.

Trappe J M 1977 Three new Endogonaceae:

Glomus constrictus,

Sclerocystis clavispora, and Acaulospora scrobiculata.

Myc otaxo n 6, 359-366.

Visser S, Griffiths C L and Parkinson D 1984 Topsoil storage

effects on primary production and rates of vesicular-

arbuscular mycorrhizal development in

.4gropyron trachycan-

turn. Plant and Soil 82, 51-60.

Wacker T L 1988 The Role of Vesicular-Arbuscular Mycor-

rhizal Fungi in the Asparagus Asparagus officonalis L.)

Agroecosystem. MS Thesis, East Lansing, Michigan State

University, 101 p.

Walker C and K oske R E 1987 Taxonomic concepts in the

Endogonaceae. IV. Glomus fasciculatum redescribed.

Myco taxon 30, 253-262.

Mycorrhizae in a Wastewater-irrigated

Documents