United States
Environmental Protection
Agency
Environmental Research
Laboratory
Corvallis OR 97330
EPA-600, 3-80-016
iry 1980
Research and Development
vvEPA
Sulfuric Acid Rain
Effects on Crop
Yield and Foliar
Injury
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate further development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment.Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. "Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ECOLOGICAL RESEARCH series. This series
describes research on the effects of pollution on humans, plant and animal spe-
cies, and materials. Problems are assessed for their long- and short-term influ-
ences. Investigations include formation, transport, and pathway studies (o deter-
mine the fate of pollutants and their effects. This work provides the technical basis
for setting standards to minimize undesirable changes in living organisms in the
aquatic, terrestrial, and atmospheric environments.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/3-80-016
January 1980
SULFURIC ACID RAIN EFFECTS ON CROP YIELD AND FOLIAR INJURY
by
Jeffrey J. Lee and Grady E. Neely
Terrestrial Division
Corvallis Environmental Research Laboratory
Corvallis, Oregon 97330
and
Shelton C. Perrigan
Crop Science Department
Oregon State University
Corvallis, Oregon 97331
ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
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DISCLAIMER
One of the principal reasons for the preparation of this report for the
Environmental Protection Agency was to supply scientifically valid information
which could be incorporated into the EPA S02-Particulate Matter Criteria
Document, presently in the final stages of preparation. A strict requirement
pertaining to that document is that any scientific information used there must
be published (or at least in press) by January 1, 1980. Because of this
demanding time constraint, it was necessary that the authors prepare this
report in a shorter time than would ordinarily be attempted, and that it be
published by EPA without undergoing peer review. We feel that early publica-
tion of these results in order to stimulate the broadest scientific discussion
prior to completion of the criteria document justified waiving our normally
more rigorous prepublication review requirements. Publication, however, does
not signify that the contents necessarily reflect the views and policies of
EPA, nor does mention of trade names or commercial products constitute
endorsement or recommendation for use.
11
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FOREWORD
Effective regulatory and enforcement actions by the Environmental Protec-
tion Agency would be virtually impossible without sound scientific data on
pollutants and their impact on environmental stability and human health.
Responsibility for building this data base has been assigned to EPA's Office
of Research and Development and its 15 major field installations, one of which
is the Corvallis Environmental Research Laboratory.
The primary mission of the Corvallis Laboratory is research on the
effects of environmental pollutants on terrestrial, freshwater, and marine
ecosystems; the behavior, effects and control of pollutants in lakes and
streams; and the development of predictive models on the movement of pollu-
tants in the biosphere.
This report describes the effects of simulated sulfuric acid rain on the
yields of several crops. Data on foliar injury are also presented. This
study was undertaken as part of an evaluation of the effects of acid rain on
agro-ecosystems.
Thomas A. Murphy, Director
Corvallis Environmental Research Laboratory
iii
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ABSTRACT
A study was undertaken to determine the relative sensitivity of major
United States crops to sulfuric acid rain. Potted plants were grown in field
chambers and exposed to simulated sulfuric acid rain (pH 3.0, 3.5, or 4.0) or
to a control rain (pH 5.6). At harvest, the fresh and dry weights of the
marketable portion were determined for 28 cultivars. Of these, yield produc-
tion was inhibited for 5 cultivars, stimulated for 6 cultivars, and ambigu-
ously affected for 2 cultivars. The results suggest that the likelihood of
yield being affected by acid rain depends on .the part of the plant utilized.
Plants were regularly examined for foliar injury associated with acid
rain. Of the 35 cultivars examined, the foliage of 31 was injured at pH 3.0,
28 at pH 3.5, and 5 at pH 4.0. Foliar injury was not generally correlated
with effects on yield.
This report covers work performed from February through November, 1979.
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CONTENTS
Foreword iii
Abstract iv
Tables v
1. Introduction 1
2. Conclusions and Recommendations . .• 2
3. Experimental Procedures 3
4. Results and Discussion 8
References 18
TABLES
1. Chemical Analyses of Soil Mixes 5
2. Chambers Used in Crop Survey 6
3. Chemical Analysis of Irrigation Water 6
4. Harvest Criteria 6
5. Experimental Conditions of Crops Surveyed 7
6. Yield of Marketable Portion of Crops 13
7. Relative Ratings of Maximum Acid Rain Injury of Leaves 14
8. Estimated Fraction of Leaf Area at Final Harvest Showing Injury
Associated with Acid Rain Treatment. . 15
9. Yields from Successive Harvests of Red Clover and Alfalfa 16
10. Classification of Results by Foliar Injury and by Yield 17
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SECTION 1
INTRODUCTION
Acid precipitation occurs over a large area of the United States. The
increased concentrations of sulfuric and nitric acids in precipitation are
derived primarily from the air pollutants sulfur doxide (S02) and oxides of
nitrogen (NO ). All states east of the Mississippi River and some western
states regularly receive precipitation which is more acidic than the expected
value of pH 5.6 for carbonic acid rain which is formed by dissolution of
atmospheric C02-1-8 In the northeastern United States, pH 3.5 is typical of
summer rains, although more acidic rains do occur.5 With the increasing use
of fossil fuels, precipitation will probably be at least as acidic in the
future.
The regions impacted or susceptible to acid rain encompass vast acreages
of fertile farmland. The potential effect on crops has been identified as a
major concern.9'10 Although some studies have been performed,11-21 there is
little documentation of acid rain effects on crop foliage or yield. Specific-
ally, it is not known whether response to acid rain is common or rare among
crops; whether this response is generally stimulatory or inhibitory in terms
of yield; or what plant characteristics might correlate with differences in
yield response. To provide partial answers to these questions, we conducted
an experimental survey to provide a comparison of the relative foliar and/or
yield sensitivities of several crops to simulated sulfuric acid rain.
In this paper, we present the results on yield and on foliar injury
ratings. Future papers will discuss findings on other growth parameters and
present photographs showing the characteristics of foliar injury caused by
simulated sulfuric acid rain.
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SECTION 2
CONCLUSIONS
Data from a single growing season on the effects of simulated sulfuric
acid rain on the yield of potted plants suggest the following tentative
conclusions.
1. The yield of dicotyledons is more likely to be adversely affected by
acid rain than the yield of monocotyledons.
2. Among dicotyledons, the yields of root crops are most likely to be
adversely affected, followed by leaf, cole, and tuber crops. Legumes and
fruit crops may be stimulated by acid rain.
3. Grain crops are unlikely to be affected, while monocotyledenous
forage crops may be more productive under acid rain conditions.
4. Foliar injury is not correlated with yield effects.
RECOMMENDATIONS
Interpretations of the data in this report should be regarded as unproven
hypotheses. Additional comprehensive experimental studies under laboratory,
greenhouse, and field conditions are necessary before the effects of acid rain
on crops can be accurately assessed.
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SECTION 3
EXPERIMENTAL PROCEDURES
Sandy loam soil was obtained from the floodplain of the Willamette River,
Oregon. The low nitrogen, or LN, mix was produced by mixing a portion of this
soil with peat moss (7.7 kg per cubic meter of soil) and 6-20-20 fertilizer
(624 grams per cubic meter of soil). The high nitrogen, or HN, mix was
produced by mixing another portion of the soil with peat moss (7.7 kg per
cubic meter of soil) and 10-20-20 fertilizer (624 grams per cubic meter).
After the soil was pasteurized by exposure to aerated steam (75°C for 40
minutes), plastic pots were filled with the mixes. The results of chemical
analyses of samples of the amended and unamended soils are given in Table 1.
For one group of crops, seeds were sieved into 3 size classes and the
most common-sized seeds were planted in 6-liter plastic pots. Two potato
pieces each containing two eyes were planted in 15-liter pots. In most cases,
plants in this group were first exposed to simulated rain treatments within
one day of planting. A second group of crops was germinated in a greenhouse
and transplanted to 6-liter plastic pots for exposure to simulated rain treat-
ments.
Crops were grown in three types of exposure chambers (Table 2). All
plants of any given crop were grown in the same type chamber. To check for
seasonal variation, radishes were planted at different times during the
growing season. Possible differences associated with chamber type were
investigated by growing radish crops in all chamber types simultaneously.
Stainless steel nozzles were used to apply simulated rain at the average
rate of 6.7 mm/hr, 1.5 hours per day, 3 days per week, for a total of 30
mm/week. The simulate^, rain in eact^ chamber contained a sto^k solution
containing 11 |jeq/l Ca ,12 neq/1 _Na , 2 |jeq/l K , 5 peq/1 Mg ,11 peq/1
S04 , 12 |jeq/l N03, and 12 peq/1 Cl . These concentrations were an approxi-
mation of non-acid rain based on a 7-year average from a site in the north-
eastern United States, after elimination of estimated sulfuric and nitric acid
components.23 The control chambers received rain containing only the stock
solution equilibrated with atmospheric C02 to approximately pH 5.6. Acid rain
chambers received rain consisting of the stock solution to which had been
added sufficient H2S04 to lower the pH to 4.0, 3.5, or 3.0. Supplemental
irrigation with well water was provided according to individual pot needs, as
determined visually. Thus, soil moisture content was similar among pots.
Water volumes applied to each pot were recorded. A chemical analysis of
irrigation water is given in Table 3.
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Crops were harvested according to various criteria (Table 4). For most
crops, the fresh weight of the marketable portion was determined at time of
harvest. The dry weights of the roots, tops and marketable portions also were
measured. Data on the non-yield portions will be presented in future papers.
All crops in acid treatment chambers were regularly examined for acid
rain injury. If noticeable injury was present, control plants were checked
for the same characteristics. When only plants in the acid treatment chambers
showed a particular type of injury, we attributed the injury to acid rain.
The date on which injury was first noticed on a particular crop was recorded,
as was the date on which more than half the plants in a particular chamber had
acid injury on at least 10% of the leaf area. Just prior to havest, the
fraction of leaf area showing acid rain injury was estimated for each plant.
Area was estimated in graduations of 5%; therefore, the presence of any injury
was always recorded as at least 5%. For some crops, leaf senescence and/or
yellowing prevented these final estimates. For fescue, ryegrass, and blue-
grass, extremely slow regrowth toward the end of the growing season resulted
in insufficient tissue for accurate injury rating at the final harvest; thus,
injury ratings refer to the first of several harvests.
Details of the experimental conditions used for each crop are summarized
in Table 5.
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Table 1. Chemical Analysis of Soil Mixes
Salts
Soil Mix mmhos/cm
Unamended 0.43
Low Nitrogen (LN) 1.35
High Nitrogen (HN) 1.80
Organic
Matter
%
0.81
1.46
1.76
Total
N %
0.06
0.07
0.08
P
ppm
13
29
29
S04-S
ppm
5.7
48.9
54.9
B
ppm
0.16
0.20
0.20
K
ppm
99
179
204
Ca
meq/
100 g
13.6
10.8
10.9
Mg
meq/
100 g
6.2
5.4
5.6
Na
meq/
100 g
0.29
0.26
0.27
CEC
meq/
100 g
20.2
20.5
21.2
Free
CaC03
%
16.7
16.8
17.0
PH
6.3
5.8
b.8
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Table 2. Chambers Used in Crop Survey
Type
Large Round
Small Round
Square
(LR)
(SR)
(SQ)
Diameter
or Length
Meters
4.6
3.0
2.4
Height
Meters
2.4
2.4
2.1
Covering
Krene
Krene
Teflon
Total
Number
4
8
20
Number per
Treatment
1
2
5
Pots per
Crop per
Treatment
14a
14
25
10 pots per treatment for potato.
Table 3. Chemical Analysis of Irrigation Water
PH
Calcium
Magnesium
Sodium
Potassium
Phosphorus
Kjeldahl-Nitrogen
Nitrate-Nitrogen
Cobalt
Copper
Iron
Molybdenum
Zinc
Aluminum
Silica
7.46
19.0 rag/1
6.1 "
9.2 "
1.7 "
0.25 "
0.07 "
2.20 "
0.39 "
0.02 "
0.23 "
0.20 "
0.16 "
0.15 (l
31.2 "
Table 4. Harvest Criteria
Maturity or senescence of control plants.
Size or maturity of marketable portion of control plants.
1.
2.
3.
4.
5.
Multiple harvests as marketable portions of plants became mature and/or
marketable.
Predetermined periodic harvests.
Premature harvests without usable measurement of yield.
-------
Table 5. Experimental Conditions of Crops Surveyed
Crop
Radish 1
Radish 2
Radish 3
Radish ,4
Radish 5
Beet
Carrot
Mustard Green
Spinach
Swiss Chard
Bibb Lettuce
Head Lettuce
Tobacco
Cabbage
Broccol i
Cauliflower
Potato
Green Pea
Peanut
Soybean 1
. 0
Soybean 3
Alfalfa
Red Clover
Tomato
Cucumber
Green Pepper
Strawberry
Oats
Wheat
Barley
Corn
Onion
Fescue
Orchardgrass
Bluegrass
Ryegrass
Timothy
*See Table 2 fc
5i* Plant.*; wpre
Cultivar
Cherry Belle
Cherry Belle
Cherry Belle
Cherry Belle
Cherry Belle
Detroit Dark Red
Danvers Half Long
Southern Giant Curled
Improved Thick Leaf
Lucullus
Limestone
Great Lakes
Burley 21
Golden Acre
Italian Green Sprouting
Early Snowball
White Rose
Marvel
Tennessee Red
OR- 10
narK ^ "''
Norman (G-00;
Vernal
Kenland
Patio
5116 Cresta
California Wonder
Quinalt
Cay use
Fieldwin
Steptoe
Golden Midget
Sweet Spanish
Alta
Potomac
Newport
Linn
Climax
ir chamber specifications.
• nr*nwn "fwim <:aoH in nntc i
Chamber
Type
LR
SR
LR
SR
SQ
SQ
SQ
SR
SR
SR
LR
LR
LR
LR
LR
LR
LR
LR
SQ
SQ
ff\
bQ
Of\
SQ
SR
SR
LR
LR
SR
LR
LR
LR
LR
LR
LR
SR
SR
SR
SR
SR
icori in i
Seed or .
Transplant
S
S
S
S
S
S
S
S
S
S
T
T
T
T
T
T
E
S
S
S
S
S
T
S
T
T
S
S
S
S
S
T
T
S
T
T
cwnnciivo r-hamh
Plants
per Pot
3
2
3
3
3
2
2
2
2
1
1
1
1
1
1
1
2
2
1
1
1
2
2
1
1
1
1
3
3
3
1
2
3
3
3
3
3
lov-c T- [
Soil
Hixc
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
LN
LN
LN
i u
LN
UN
1 U
LN
LN
LN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
HN
Ma nf- c i
Supplemental
Fertilizer
g/pot
0,5 Urea
1.0 Urea
0.5; 4.1
2.0 Urea
1.0 Urea
0.5 Urea
1.0 Urea
1.2 Urea
0.5 0-20-20
4.1 0-10-10
0.5; 4.1; 2.1
0.5; 4.1
0.5; 0.0; 2.1
1.0 Urea
0.5; 4.1
2.0; 4.1
0.5; 4.1
1.0; 8.2
LJO»~C\ c + a v»t &tf "in rt
Pesticide
Used6
D
D
D, M
D
D
D
D
D
D
D .
D
D
D
D
D
D
D
D
maanKrtiico
Planting
Date
4/19
5/25
9/26
9/26
9/26
7/26
7/26
5/25
5/25
5/25
8/31
8/31
5/02
2/21
2/21
2/21
4/19
4/19
7/26
7/26
f\ /rtr:
9/Ob
9/05
Q /nc.
y/ob
5/25
5/25
5/16
7/17
5/16
(g)
4/19
4/19
4/19
7/23
4/19
6/14
6/14
5/25
6/14
6/14
anH tfancr
Date
of First
Exposure
4/20
5/26
9/26
9/27
9/27
7/26
7/26
5/26
5/26
5/26
9/14
9/14
6/13
4/20
4/20
4/20
4/20
4/20
7/26
7/26
1 U/ U£
o /i T
9/ 1 1
Q /I T
y/ 1 1
5/26
5/26
6/29
7/18
6/28
4/20
4/20
4/20
4.20
7/23
4/20
7/07
7/07
5/26
7/07
7/07
plantar! tn n
Harvest,
Criteria
2
2
2
2
2
2
1
2
2
2
2
5
1
2
3
3
1
2
5
5
5
2
2
3
5
1
3
1
1
1
5
1
4
2
2
4
2
rttc ncoH ir
Final
Harvest
Date
5/21
6/21
10/31
10/31
10/31
9/25
11/01
6/26
6/29
8/07
11/03
11/15
8/08
7/17
6/10
6/11
8/15
6/22
9/26
10/24
10/03
10/02
10/25
10/01
9/24
10/16
8/06
7/37
7/31
9/05
5/17
11/20
9/25
11/07
11/16
9/19
* oYnncur
chambers. E: Potato eyes planted in pots used in exposure chambers.
jSee Table 1 for soil specifications.
"Where more than one number is given, first number refers to grams of urea; second to 0-10-10;'third to 10-20-20.
J): Oiazonon, M: Maneb.
See Table 4 for harvest criteria.
Transplants obtained from commercial grower.
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SECTION 5
RESULTS AND DISCUSSION
The yield results are summarized in Table 6. For each crop, the fresh
and dry weights of the marketable portions of plants receiving the pH 5.6 rain
(the controls) are given on a per pot basis. The mean yields of crops
subjected to simulated acid rain are presented as ratios to the control mean,
as is the standard error. Provided that the F-test from a one way analysis of
variance was significant at the 0.10 level, two-sided t-tests were used to
determine which treatment means were significantly different from the control.
Foliar injury results are summarized in Tables 7 and 8. Injury ratings,
made for all crops during the growing season, are given in Table 7. Yellowing
and/or senescence of control leaves of several crops prevented estimating the
leaf area exhibiting acid rain injury at harvest; results for those crops for
which estimates could be made are given in Table 8. Since foliar injury was
rated in discrete steps, a rating of 5% indicated that a plant showed some,
possibly minute, acid rain injury.
DICOTYLEDONS
As a group, dicotyledons were more susceptible to foliar injury by simu-
lated sulfuric acid rain than were monocotyledons. Although stimulation of
yield was observed for both monocotyledons and dicotyledons, inhibition of
yield was observed only for dicotyledons. The various groups of dicotyledons
are discussed in descending order of adverse effects on yield and ascending
order of positive effects.
Root Crops
All three root crops (radish, beet, carrot) had foliar injury associated
with pH 3.0 treatments; radish and beet were also injured at pH 3.5 (Table 7).
Since root crops frequently are marketed with leaves attached, this type of
disfiguration could adversely affect marketability. For radish, injury at
harvest ranged up to 25% of the leaf area; this was the crop most susceptible
to foliar injury (Table 8). Beet showed less leaf injury at harvest (Table
8), but was one of only five crops injured at pH 4.0 (Table 7). Since all
mature beet leaves developed a mosaic pattern which may have partially masked
acid rain injury, the results in Table 8 for beet may be underestimates.
In terms of yield, carrot was the most sensitive root crop, followed by
radish and beet (Table 6). Although there was no apparent acid rain foliar
injury, the yield of carrots at pH 4.0 was, on average, only 73% of that of
the control plants.
8
-------
Radish was grown in five independent studies. Plants grown earlier in
the year (Radish 1 and 2) were somewhat more susceptible to foliar injury than
those grown toward the end of the growing season (Radish 3, 4, and 5 in Tables
7 and 8). These differences may have been associated with the high temper-
atures (up to 40°C) which occurred during the earlier period. No such
temporal differences in effect on marketable yield were apparent.
In one radish study (Radish 5) plants in all five control chambers were
heavily damaged by slugs and twelve-spotted beetles, while plants in the
acid-treatment chambers were, at most, only slightly damaged. The yield of
the control plants consequently might have been somewhat reduced, resulting in
artificially high yield ratios for the acid-treatment plants. However, ratios
among acid treatments (e.g., pH 3.0 to pH 3.5) in this study were similar to
those for the other radish studies.
Although the reason for different degrees of pest damage is not clear, it
does suggest varying responses of faunal populations to different levels of
rain acidities. Less slug damage to acid-treated crops was also observed a
year earlier with radish and onion. Control chambers were in different loca-
tions during the two seasons, thus eliminating chamber location as a possible
cause for slug damage.
Leaf Crops
The foliage of Swiss chard, mustard greens, and spinach was injured by
acid rain to the extent that marketability was affected. Lettuce (bibb and
head) and tobacco were less severely affected. Cabbage was the least sensi-
tive to acid rain (Tables 7 and 8). The only crop to have less yield due to
exposure to acid rain, as measured by weight of foliage, was mustard greens
(Table 6). However, Mohamed11 found that acid rain at approximately pH 4
inhibited potted lettuce plants.
Cole Crops
Acid treatments of pH 3.0 and pH 3.5 caused foliar injury of broccoli and
cauliflower. Cabbage leaves were injured only at pH 3.0 (Tables 7 and 8).
Only radish was more extensively injured than cauliflower at pH 3.0 (Table 8).
The waxy foliage of these cole crops afforded, at most, partial protection
from acid rain injury.
Only broccoli showed significant yield effects; at pH 3.0 yield was lower
than the control (Table 6). In a field study in New York State, Mohamed found
that cabbage (cv. King Cole) was inhibited by exposure to acid rain (pH 3.0)
during the first week after seedling emergence.11
Tuber Crop
The one tuber crop studied (potato) had a mixed response to simulated
acid rain. Fc-liar injury was observed for the pH 3.0 and 3.5 treatments
(Table 7). Yield, however, was inhibited by pH 3.0 rain, and simulated by pH
3.5 and 4.0 rain; the stimulatory effects at pH 3.5 and 4.0 were, however,
significant only for fresh weight (Table 6).
-------
Legumes
Acid rain treatments of pH 3.0 and pH 3.5 injured the foliage of all
eight legume cultivars (Table 7). Of the three legumes grown to harvest
(green pea, alfalfa, and red clover), only alfalfa yield was affected by acid
rain; the yield of alfalfa plants receiving treatments of pH 3.5 and pH 4.0
was greater than the yield of control plants (Table 6).
The yield responses of red clover and alfalfa were consistent among the
successive harvests (Table 9). Although not statistically significant,
alfalfa yields tended to be lower at pH 3.0. Greater yields at intermediate
pH values (Table 9) suggest competition between stimulatory and inhibitory
effects of acid rain.
Fruit Crops
Acid rain severely injured the leaves of tomato, cucumber, and green
pepper at pH 3.0; less severe injury occurred at pH 3.5 (Table 7). Although
the leaves of green pepper were also injured at pH 4.0 (Table 7), this injury
was not identifiable at final harvest (Table 8). Strawberry leaves sustained
only minute injury (Table 7) which was not identifiable at final harvest
(Table 8).
The yield of crops grown to harvest (that is, all except cucumbers)
frequently was greater for plants receiving acid rain than for control plants.
In no case did acid rain cause as ignificantly smaller yield than did control
rain (Table 6). However,.at pH 3.0 injury to tomato fruits was severe enough
to adversely affect marketability. In contrast to our results, Mohamed11
found yields lower than control for green peppers (cv. Stoddans Select) and
tomatoes (cvs. Tiny Tim' and New York) subjected to pH 3.0 simulated rain.
MONOCOTYLEDONS
Monocotyledons were generally less susceptible to acid rain injury of
foliage than were dicotyledons. No significant adverse effects on yield were
found. Groups of monocotyledons are discussed in increasing order of stimula-
tory effects on yield.
Grain Crops
Small grain crops (oats, wheat, barley) were the crops least sensitive to
acid rain. The yields of grain (Table 6) were not affected by the acid treat-
ments, and no foliar injury was apparent (Table 7).
Corn was harvested when the plants were tall enough to interfere with
spray from the nozzles (approximately 1 m). Although the foliage was injured
(Table 7), the total above ground weight (stems plus leaves) of plants
receiving pH 3.0 rain was apparently larger than the control plants. The
difference, however, was only marginally significant (Table 6).
10
-------
Bulb Crop
Onion bulbs grown under acid treatments did not differ significantly from
controls. There was, however, a suggestion of heavier bulbs for the acid-
treated plants (Table 6); stimulation of these specialized leaves would be
consistent with the results for corn, orchardgrass, and timothy. No foliar
injury was identified (Tables 7 and 8).
Forage Crops
Acid rain
bluegrass, rye,,
4.0 (Tables 7 and 8).
ain at pH 3.0 and 3.5 caused foliar injury of fescue, orchardgrass,
ryegrass and timothy. Bluegrass was only slightly injured at pH
7 and 8).
Although injured by acid rain, orchardgrass and timothy were signifi-
cantly more productive under the pH 3.0 treatment than under the control rain.
While not significantly different from the control, the results at pH 3.5 also,
suggested higher productivity (Table 6). In contrast, Crowther and Ruston12
found that adding dilute sulfuric acid at pH values above 2.0 to soil had no
effect on the productivity of timothy during the first year of exposure; in
the third season productivity was inhibited at pH 3.4 and lower.
Acid rain effects on yield were indicated for fescue, although no treat-
ment produced significant differences. No effects were found for bluegrass or
ryegrass productivity'(Table 6).
Summary of Results on Foliar Injury and Yield
A total of 35 cultivars, including 4 soybean cultivars, was examined for
foliar injury associated with acid rain. Of these, 31 were injured at pH 3.0,
28 at pH 3.5, and 5 at pH 4.0 (Table 7).
Data on both foliar injury and on yield were obtained for 28 crops,
resulting in 84 crop-treatment combinations (28 crops times 3 acid treat-
ments). Table 10 shows the results of classifying these combinations by
effects on foliar injury and effects on yield.
Of the 84 crop-treatment combinations, 32 showed no effect on either
yield or foliar injury. Foliar injury without yield effects was found for 30
combinations and yield effects without foliar injury for 6 combinations.
Yield effects with foliar injury occurred for 16 combinations.
Foliar injury was observed on a total of 46 of the 84 combinations. All
but 5 of these were at pH 3.0 or 3.5. Yields higher than the control were
found for 7 of these 46 crop-treatment combinations, and lower yields for 9 of
46 (Table 10). Thus, apparent foliar injury was not necessarily indicative of
lower yield.
In 11 of the 84 crop-treatment combinations (6 at pH 3.0; 3 at pH 3.5; 2
at pH 4.0), the acid-treated plants had Tower yields than the controls. For
another 11 crop-treatment combinations (5 at pH 3.0; 3 at pH 3.5; 3 at pH
4.0), the yields of acid-treated plants were higher than the controls. The
11
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numbers of combinations having foliar injury were similar for both the stimu-
lated and inhibited groups (Table 10). Therefore yield could be affected
without apparent foliar injury. Moreover, acid rain effects could not be
characterized as generally stimulatory or generally inhibitory of yield.
However, results of this study indicate this is a possibility for specific
groups of crops, as discussed above.
Caution should be used in drawing conclusions from these data. They were
obtained by subjecting potted plants to simulated sulfuric acid rain in field
exposure chambers, rather than to ambient rain under field conditions. The
results pertain to a single growing season, a particular soil, and a partic-
ular location; thus, reproducibility of results has yet to be demonstrated.
Interactions with air pollutants, other contaminants, or various environmental
factors could affect the results. Interpretations of the data should be
viewed as hypotheses to be tested under different conditions.
12
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Table 6. Yield of Marketable Portion of Crops
to
FRESH WEIGHT OF
Crop
Radish 1
Radish 2
Radish 3
Radish 4
Radish 5
Beet
Carrot
Mustard Green
Spinach
Swiss Chard
Bibb Lettuce
Tobacco
Cabbage
Broccol i
Cauliflower
Potato
Green Pea
Alfalfa
Red Clover
Tomato
Green Pepper
Strawberry
Oats
Wheat
Barley
Cornc
Onion
Fescue
Orchardgrass
Bluegrass
Ryegrass
Timothy
From
Control
Plants
g/pot
43.23
42.12
47.74
26. 79.
18.07d
55.07
138.54
59.28
32.33
99.72
129.97
240.81
44.63
69.62
691 . 79
21.55
302. 88
193.12
113.04
410.11
YIELD PER POT
From Treatment Plants
Ratio to Control Yield
pH 3.0
0.44§
0.40§
0.24§
0.38§
0.59
0.57§
0.56§
0.70§
0.85
0.90
1.01
0.91
0.75§
1.03
0.92§
1.04
1.31§
1.05
1.72S
1.01
pH 3.5
0.83§
O.Slt
0.73§
1.03
1.41
1.02
0.55§
0.87*
0.99
1.04
1.02
1.47
0.92
1.46
1.11T
-0.98
1.01
1.20t
1.72§
1.12
pH 4.0
0.92
0.84*
1.14*
0.86
1.56
1.09
0.73t
0.83t
0.90
0.94
1.03
1.01
0.89
1.20
1.07*
1.05
0.95
1.05
1-51§
1.04
SEa
0.04
0.06
0.06
n OQ
Q
o.n
0.08
0.05
0.07
0.07
0.04
0.17
0.07
0.15
0.03
0.04
0.07
0.06
0.13
0.06
Sig'nb
Level
0. 000§
0.000§
0.000§
o.ooo§d
0.011T
0.001§
0.003§
0.388
0.561
0.932
0.131
0.063t
0.185
0.001S
0.674
0.001§
0.103*
0.001§
0.426
From
Control
Plants
g/pot
2.66
2.51
2.54
1.71 .
1.08d
10.38
13.36
7.30
3.58
16.66
6.13
27.64
29.89
6.07
6.36
149.53
4.21
28.72
31.05
12.72
31.41
29.30
34.71
35.56
29.11
25.25
22.47
12.81
20.24
21.07
DRY
WEIGHT OF YIELD PER POT
From Treatment Plants
Ratio to Control Yield
pH 3.0
0.45§
0.47§
0.31§
0.42§
0.64
0.55T
0.53§
0.69§
0.93
0.98
1.05
0.97
0.87
0.75§
1.01
0.86§
1.06
0.94
0.99
1.13
0.92
0.97
1.05
1.13*
1.10
0.96
1.23T
0.98
0.99
1 . 24f
pH 3.5
0.79§
0.83t
0. 77§
1.01
1.40
1.03
0.57§
0.90
1.03
1.04
0.97
0.97
1.19
0.88
1.39
1.05
0.97
I.31§
1.03
1.17t
1.00
0.98
1.06
0.95
1.14
1.07
1.10
0.94
0.98
1.09 -
pH 4.0
0.86T
0.86*
1.15*
0.87
1.52
1.10
0.69§
0.86*
0.98
1.03
1.07
1.03
0.92
0.91
1.27
1.05
1.06
1.17§
1.02
1.06
1.00
0.98
1.00.
0.99
1.09
0.92
1.00
1.00
0.96
0.86
SEa
0.04
0.05
0.05
0.11
0.08
0.06
0.08
0.06
0.03
0.03
0.13
0.06
0.13
0.03
0.06
0.05
0.04
0.06
0.05
0.06
0.05
0.05
0.06
0.04
0.07
0.05
0.03
0.07
Sig'nb
Level
0.000§
0.000§
0.000§
0.000|
0.012§
0.000§
0.002§
0.871
0.827
0.087*
0.443
0.378
0.078T
0.164
0.000§
0.547
0. 000§
0.911
0.207
0.500
0.976
0.727
0.085*
0.295
o.oist
0.097*
0.725
0.787
0.003§
.Standard error of the mean, divided by mean control yield.
^Significance level of F-test for treatment effects.
,For corn, data refer to total above ground (stem plus leaves) weight.
Unreliable data for control; see text.
*Significant effect with p S 0.10 for two-sided t-test.
tSignificant effect with p S 0.05 for two-sided t-test.
§Significant effect with p % 0.01 for two-sided t-test.
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Table 7. Relative Ratings of Maximum Acid Rain Injury of Leaves
Crop
Radish 1
Radish 2
Radish 3
Radish 4
Radish 5
Beet
Carrot
Mustard Greens
Spinach
Swiss Chard
Bibb Lettuce
Head Lettuce
Tobacco
Cabbage
Broccoli
Cauliflower
Potato
Green Pea
Peanut
Soybean 1
Soybean 2
Soybean 3
Soybean 4
Alfalfa
Red Clover
Tomato
Cucumber
Green Pepper
Strawberry
Oats
Wheat
Barley
Corn
Onion
Fescue
Orchardgrass
Bluegrass
Ryegrass
Timothy
Acid Rain Injury by pH of Treatment
3.0 3.5 4.0
+ (- + 0
++ + 0
+ + 0
+ + o
+ + o
+ + +
+ 00
++ + O
++ + o
++ + +
+ + o
+ + 0
+ + o
+ 00
+ + 0
++ + 0
+ + o
+ + 0
+ + 0
+ + +
+ + o
+ + 0
+ + 0
+ + 0
+ + 0
++ + o
++ + 0
++ + +
+ 00
000
000
000
+ 00
000
+ + o
+ + 0
+ + +
+ + 0
+ + o
++ At least half the plants had 10% or more of leaf area injured by acid rain
at some time during growth.
+ Acid rain injury noted, but at no time during growth did more than half of
plants show 10% or more of leaf area injured by acid rain.
o No apparent acid rain injury on leaves.
14
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Table 8. Estimated Fraction of Leaf Area at
Associated with Acid Rain Treatment
Final Harvest Showing Injury
Crop
Radish 1
Radish 2
Radish 3
Radish 4
Radish 5
Beet
Carrot
Mustard Greens
Spinach
Bibb Lettuce
Head Lettuce
Cabbage
Broccol i
Cauliflower
Green Pea
Alfalfa
Red Clover
Green Pepper
Strawberry
Corn
Onion
Fescue3
Orchardgrass
Bluegras|
Ryegrass
Timothy
Acid Rain Injury
3.0
17.5
15.4
11.4
7.9
11.6
5.0
0.0
10.4
11.8
5.0
4.6
4.3
5.0
14.6
5.0
4.3
5.0
5.0
0.0
5.0
0.0
7.9
6.1
5.0
5.0
4.3
Percent of
3.5
5.0
5.0
5.0
4.3
4.8
1.2
0.0
4.3
4.0
0.0
0.0
0.0
3.2
0.4
5.0
0.4
0.0
0.0
0.0
0.0
0.0
5.0
1.8
3.6
0.4
1.4
Leaf Area
4.0
0.0
0.0
0.0
0.0
0.0
0.2
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.0
0.4
0.0
0.0
by pH of Treatment
Maximum
25
20
15
10
15
5
0
15
15
5
5
5
5
30
5
5
5
5
0
5
0
10
10
5
5
5
Estimates made at first of multiple harvests, when foliar material was most
abundant.
15
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Table 9. Yields from Successive Harvests of Red Clover and Alfalfa.
Crop
Red Clover
(planted 5/25)
Alfalfa
(planted 5/25)
Harvest
Date
07/26
08/17
09/06
10/02
Total
07/26
08/27
10/03
Total
From
Control
Plants
g/pot
7.53
7.09
7.72
8.71
31.05
9.59
8.51
10.61
28.72
Dry Weight of Yield Per Pot From
Treatment Plants
Ratio to Control Yield
pH 3.0
0.84*
1.04
1.05
1.04
0.99
0.96
o.sit
1.03
0.94
pH 3.5
0.99
1.03
1.01
1.10
1.03
1.25§
1.31§
1.36§
1.31§
pH 4.0
1.11
0.92
1.04
1.01
1.02
1.12
1.06
1.31§
1.17§
SE9
0.07
0.05
0.07
0.05
0.04
0.06
0.06
0.07
0.05
Sig'nb
Level
0.046T
0.267
0.952
0.567
0.911
0.004§
0.000§
0.001§
0.000§
.Standard error of the mean divided by mean control yield.
Significance level of F-test for treatment effects.
^Significant effect with p ^ 0.10 for two-sided t-test.
tSignificant effect with, p ^ 0.05 for two-sided t-test.
§Significant effect with p S 0.01 for two-sided t-test.
16
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Table 10. Classification of Results by Foliar Injury and by Yield. Entries
are Number of Crop-Treatment Combinations in Each Category.
Foliar Injury:
++ At least half the plants had 10% or more of their leaf area injured
by acid rain at some time during growth.
+ Acid rain injury noted, but at no time did half the plants have 10%
or more of leaf area injured by acid rain.
o
Yield:
No apparent acid rain injury on leaves.
Yield of treatment plants greater than yield of control plants.
Yield of treatment plants not significantly different from yield of
control plants (p ^ 0.10).
Yield of treatment plants less than yield of control plants.
Foliar Injury
Total
Yield
o
Total
1
4
2
7
6
26
7
39
4
32
2
38
11
62
11
84
17
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REFERENCES
1. Cogbill, C. V. and G. E. Likens. 1974. Acid precipitation in north-
eastern United States. Water Res. Res. Khll33-1137.
2. Gambell, A. W. and D. W. Fisher. 1966. Chemical composition of rain-
fall, eastern North Carolina and southeastern Virginia. U.S. Geological
Survey Water Supply Paper 1535-K. 41 pp.
3. Haines, B. 1978. Acid precipitation in southeastern United States: a
brief review. Georgia J. Sci. 37:185-191.
4. Likens, G. E. and F. H. Bormann. 1974. Acid rain: a serious regional
environmental problem. Sci. 184:1176-1179.
5. Likens, G. E. , R. W. Wright, J. N. Galloway and R. J. Butler. 1974.
Acid rain. Sci. Am. 241:42-51.
6. Larson, T. V., R. J. Charlson, E. J. Knudson, G. D. Christian and H.
Harrison. 1975. The influence of a sulfur dioxide point source on the
rain chemistry of a single storm in the Puget Sound region. Water, Air,
and Soil Pollut. 4:319-328.
7. Liljestrand, H. M. and J. J. Morgan. 1978. Chemical composition of acid
precipitation in Pasadena, Calif. Environ. Sci. Techno!. 1^:1271-1273.
8. McColl, J. G. and D. S. Bush. 1978. Precipitation and throughfall
chemistry in the San Francisco Bay area. J. Environ. Qual. 1_;352-357.
9. Galloway, J. N. , E. B. Cowling, E. Gorham and W. W. McFee. 1978. A
national program for assessing the problem of atmospheric deposition
(acid rain). A report to the Council on Environmental Quality. Natural
Resource Ecology Laboratory, Colorado State University, Ft. Collins.
10. Electric Power Research Institute (EPRI). 1979. Ecological effects of
acid precipitation. Report of workshop held at Gatehouse-of-Fleet,
Galloway, U.K., September 4-7, 1978. EPRI SOA77-403.
11. Mohamed, M. B. 1978. Response of vegetable crops to acid rain under
field and simulated conditions. Ph.D. Thesis, Cornell University.
12. Crowther, M. A. and A. G. Ruston. 1911. The nature, distribution, and
effects upon vegetation of atmospheric impurities in and near an indus-
trial town. Journ. Agr. Sci. 4:25-55.
19
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13. Evans, L. S. and G. S. Rayner. 1976. Acid rain research program:
annual progress report—September 1975-June 1976. Brookhaven National
Laboratories. BNL 50575. 67 pp.
14. Evans, L. S. , N. F. Gmur and F. DaCosta. 1977. Leaf surface and histo-
logical perturbations of leaves of Phaseolus vulgaris and Helianthus
annus after exposure to simulated acid rain. Amer. J. Bot. 64:903-913.
15. Evans, L. S., N. F. Gmur and J. J. Kelsch. 1977. Perturbations of upper
leaf surface structure by acid rain. Environ, and Exper. Bot. 17:145-
149.
16. Evans, L. S. 1977. Acid rain research program: annual progress report—
July 1976-Sept. 1977. Brookhaven National Laboratories BNL 50786. 104
pp.
17. Evans, L. S. and T. M. Curry. 1979. Differential responses of plant
foliage to simulated acid rain. Amer. J. Botany 66:953-962.
18. Ferenbaugh, R. W. 1976. Effects of simulated acid rain on Phaseolus
vulgaris L. (Fabaraea). Amer. J. Botany 63:283-288.
19. Irving, P. M. and J. W. Miller. 1977. Response of soybeans to acid
precipitation alone and in combination with sulfur dioxide. In: Radio-
logical and environmental research division annual report. Ecology.
January-December 1977. Argonne National Laboratory, Argonne, Illinois.
ANL-77-65, Part III, p. 24-27.
20. Irving, P.M. and J. E. Miller. 1978. Response of soybeans to acid
precipitation alone and in combination with sulfur dioxide. In: Radio-
logical and environmental research division annual report. Ecology.
January-December 1978. Argonne National Laboratory, Argonne, Illinois.
ANL-67-65, Part III, p. 17-20.
21. Irving, P.M. 1978. Induction of visible injury in chambergrown soybeans
exposed to acid precipitation. In: Radiological and environmental
research division annual report. Ecology. January-December 1978.
Argonne National Laboratory, Argonne, Illinois. ANL-78-65, Part III, p.
24-25.
22. Kratky, B. A., E. T. Fukunaga, J. W. Hylin and R. T. Nakano. 1976.
Volcanic air pollution: deleterious effects on tomatoes. J. Environ.
Qua!. 3:138-140.
23. Likens, G. E. and F. H. Bormann. 1972. Nutrient cycling in ecosystems.
In: Ecosystem structure and function, p. 25-47. Proc. 31st Annual
Biology Colloquium, Oregon State University Press, Corvallis, Oregon.
20
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TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/3-80-016
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
Sulfuric Acid Rain Effects on
Crop Yield and Foliar Injury
5. REPORT DATE
January 1980 issuing date
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
3. PERFORMING ORGANIZATION REPORT NO.
Jeffrey J. Lee, Grady E. Neely
Shelton C. Perrigan
9. PERFORMING ORGANIZATION NAME AND ADDRESS
10. PROGRAM ELEMENT NO.
Corvallis Environmental Research Laboratory, EPA
200 SW 35th Street
Con/all is, OR 97330
11. CONTRACT/GRANT NO.
12. SPONSORING AGENCY NAME AND ADDRESS
same
13. TYPE OF REPORT AND PERIOD COVERED
inhouse - final
14. SPONSORING AGENCY CODE
EPA/600/02
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A study was undertaken ^determine the relative sensitivity of major U. S.
crops to sulfuric acid rain. Plants were grown under controlled environmental
conditions and exposed to simulated acid rain of three sulfuric acid concen-
trations (pH 3.0, 3.5, 4.0) or to a control rain (pH 5.7). Qnjury to foliage
and effects on yield were common responses to acid rain. However, foliar
injury was not a good indicator of effects on yield. I
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRI
TORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Rainfall, pollution, sulfuric acid,
sulfates, ecology, soil chemistry,
agricultural products
Acid rain, agricultural
crops
02/D
06/F
18. DISTRIBUTION STATEMEN1
Release to public
19. SECURITY CLASS (ThisReport)
unclassified
21. NO. OF PAGES
26
20. SECURITY CLASS (Thispage}
unclassified
22. PRICE
EPA Form 2220-1 (Rev. 4-77)
21
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