mycorrhizae in a wastewater-irrigated
TRANSCRIPT
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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
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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
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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
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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
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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.
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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
Auto c la ve d 3 .2 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
Auto c la ve d 5 .7 b 0 .0 b
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.
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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
G. fasc i cu la tum.
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
G. fasc i cu la tum.
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
-
8/11/2019 Mycorrhizae in a Wastewater-irrigated
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.
Brit. Mycol. Soc. 55, 158-161.
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.
-
8/11/2019 Mycorrhizae in a Wastewater-irrigated
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.
Brit. Mycol. Soc. 83, 193-202.
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.