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Abstract
Companion planting is a legitimate horticultural practice that uses ecological principles of beneficial plant relationships to enhance
establishment and survival of desired plants. The concept has been mythicized by nonscientists who have assigned zodiac, occult, or
other pseudoscientific qualities to plants, which creates confusion for home gardeners. This publication explains the science behind
companion planting, while debunking the misconceptions found in numerous popular gardening books and websites. Gardeners who
use companion planting in a scientifically sound manner can improve plant health and productivity, decrease damage from insects and
disease, and decrease the need for pesticides and fertilizers—all part of IPM (Integrated Pest Management) and PHC (Plant Health
Care) strategies.
Popularized Forms of Companion Planting
Gardeners often hear about “companion planting” as they
prepare their vegetable gardens and flower beds. Popular books,
charts, and online resources about companion plants are readily
available, but most lack any credible, supporting science.
• Folklore companion plants (Figure 1, top left). Many
centuries ago, plants were associated with the four elements
(earth, air, fire, and water) and signs of the zodiac. One of
the outcomes of this belief system is the practice of planting
together those species that “love” each other (Jeavons 2012;
Riotte 2004), and “snuggle for protection” (Hemenway
2001). Assigning human characteristics and emotions to
other species, which is called anthropomorphism, allows
people to feel more connected to the rest of the living world.
• Companion plants determined through sensitive
crystallization (Figure 1, bottom left). This is one of several
pseudoscientific practices included in biodynamics, which is
a form of organic agriculture developed almost a century
ago (Chalker-Scott 2013). Sensitive crystallization involves
interpreting patterns that plant extracts make as they dry,
allowing practitioners to declare which plants are
compatible with one another (Philbrick and Gregg 1966;
Riotte 2004).
• Permaculture companion plants (Figure 1, right).
Permaculture is a philosophical belief system that includes
both scientific and pseudoscientific practices. Practitioners
believe that plants do not necessarily compete with one
another (Holmgren 2002), so lists of recommended plants
include invasive species (Mollison 1994). For example,
companion planting includes the use of Scotch broom (a
listed noxious weed in some states, including Washington;
https://www.nwcb.wa.gov/weeds/scotch-broom) and other
related broom species as nitrogen-fixing companion
plantings for fruit trees. Not only does the broom compete
for water and nutrients but it produces vast numbers of seed
that only add to the spread of this noxious weed.
Popularized versions of companion planting are complicated,
contradictory, and confusing. The science behind companion
planting is substantial, enlightening, and more practical than any
myth-based information.
GARDENING WITH
COMPANION PLANTS
HOME GARDEN SERIES
PAGE 2
Figure 1. A sampling of companion plant charts available online (top left).
Biocrystallization of grape juice from integrated, organic, and biodynamic
viticulture (bottom left). WSDA noxious weed Cytisus scoparius planted as a
companion plant at a permaculture farm (right). Photo credits: (top left)
screenshot captured from amazon.com/companion+plants+chart; (bottom left)
Jürgen Fritz through Wikimedia Commons; (right) Linda Chalker-Scott.
Science-Based Companion Planting
From a scientific perspective, companion planting unites two
fields of study: agriculture and ecology. Agricultural research
has provided us with the practices of polyculture and
intercropping, which involve planting mutually beneficial
species. Ecological studies have described naturally occurring,
beneficial associations among plants in nonagricultural
environments. Together, these two sciences define symbiotic
relationships among plants and their associated, beneficial
insects and microbes.
In the scientific literature you will find a variety of phrases used
interchangeably with companion planting. They include:
• intercropping—Generally used to describe relatively simple
systems, where one or a few species are used in alternate
rows; agricultural terminology (Figure 2, top left).
• plant association—Plant species that are often found
together in natural environments; ecological terminology
(Figure 2, bottom left).
• nurse plant (or pioneer species)—A plant that enhances
survival of newly germinated seedlings by providing shade,
blocking wind, or otherwise moderating the microclimate;
ecological terminology (Figure 2, top right).
• polyculture—More complex than intercropping, as it
involves multiple species; often used to describe hedgerows,
windbreaks, and other multispecies plant systems;
agricultural and ecological terminology (Figure 2, bottom
right).
PAGE 3
Figure 2. Intercropping coconut and Tagetes erecta (marigold) in Kerala, India
(top left). Desert oasis plant association along streambed (bottom left). Nurse
log in the forest (top right). A polycultural landscape mixing vineyards and
annual crops with woody hedgerows and trees in Charente, France (bottom
right). Photo credits: (top left) Ezhuttukari through Wikimedia; (bottom left)
Linda Chalker-Scott; (top right) Linda Chalker-Scott; (bottom right) JLPC through
Wikimedia.
Whenever a plant begins to grow in the garden, it alters its
environment physically, chemically, and biologically (Table 1).
Some of these changes—reduced soil water, nutrients, and
sunlight, for instance—make it more difficult for neighboring
plants to grow. But other alterations—increased shade,
decreased evaporation and wind—may enhance the germination,
growth, and survival of some species. In ecology, pioneering
species are those that pave the way for plants less adaptable to
extreme environmental conditions (Close et al. 2005).
Pioneering species may be nitrogen-fixers (like beans, peas, and
other legumes), shade providers, or serve as habitats for
microbes and insects. Complex associations of plants, insects,
and microbes can have positive, negative, or minimal effects on
one another. When we are able to tease out the positive
associations, we can use the information for planting and
maintaining our gardens.
All of the benefits of companion plants described in Table 1
have been documented through research and used in the
management of agricultural, ornamental, and restoration
landscapes.
PAGE 4
Table 1. Environmental modifications made by plants.
Physical alterations
Examples
• Compaction reduction
All plants will reduce soil compaction, through insulation above or root support
below
• Wind block
Taller shrubs and trees can redirect wind
• Shade
The amount of shade provided depends on plant size, persistence of leaves, and
other morphological characteristics
• Temperature moderation
Low-growing species, such as ground covers, protect soil from temperature
fluctuations
• Moisture conservation
Increased shade and temperature moderation help conserve soil moisture
• Structural support
Sturdy, upright species provide vertical space for climbing plants
• Erosion control
Roots of all plants help reduce erosion from water runoff; low growing species,
such as ground covers, reduce erosion due to wind
Chemical alterations
• Increased organic matter
All plant material left on soil will be naturally incorporated into the soil profile
• Nitrogen fixation
Nitrogen-fixing species including legumes, alder, and hundreds of other species*
• Nutrient availability
Increasing densities of plants will decrease nutrient levels
• Water availability
Increasing densities of plants will decrease water availability
• Salt accumulation
Salsola soda, Portulaca oleracea, and other species found in high-salt
environments take up salt, allowing more sensitive plants to grow*
• Heavy metal accumulation
A variety of plants can take up and retain heavy metals*
• Volatile organic compounds (VOCs)
Many plants can produce VOCs which can have attractant or repellent effects on
other species*
Biological alterations
• Weed control
Dense plantings can reduce or eliminate weeds (Breitenmoser et al. 2022)
• Pest control
A diverse planting palette can interfere with pest feeding and reproduction, and
provide habitat for natural predators of pest insects*
• Disease control
Plant diversity decreases likelihood of disease spread, as many pathogens are host
specific*
• Mycorrhizal enhancement
Many desirable plant species, especially woody species, are colonized by
beneficial mycorrhizal fungi*
*See additional information in text.
PAGE 5
Chemical Alterations
1. Nitrogen fixation
While gardeners know about the value of nitrogen-fixing
vegetables like peas and beans, they are often unaware that many
other species besides legumes can add nitrogen to the soil
(Tedersoo et al. 2018). Nitrogen-fixing trees, shrubs, perennials,
and annuals (Figure 3) can transfer nitrogen to the soil
microbiome in a process called rhizodeposition (Fustec et al.
2010). Some nitrogen-fixers pull double duty, both increasing
the nitrogen levels of the soil as well as attracting pollinators
(Abad et al. 2019).
Though this process does not directly supply other plants with
nutrients, many of the beneficial bacterial and fungal species that
are recipients also colonize and benefit plant roots. There is also
some evidence that fine roots of neighboring plants can take up
nitrogen as well if they are in the right place at the right time
(Paula et al. 2015). Nitrogen-fixing species enrich the soil by
improving its microbiome; they do not deliberately provide
nitrogen to other plant species nor do nitrogen-fixing companion
plants always improve the health and survival of other plants
(Milne et al. 2021). Furthermore, yields of the nitrogen-fixing
species can suffer if they are not competitive with the other crop
plants (Monti et al. 2016).
Figure 3. Nitrogen-fixing plants include trees (alder; top right), shrubs (tree
lupine; center right), perennial flowers (mixed sweet peas; bottom right), and
annual vegetables (peas; left) for use in gardens and landscapes. Photo credits:
(top right) Linda Chalker-Scott; (center right) Linda Chalker-Scott; (bottom right)
Acabashi through Wikimedia; (left) Karolina Grabowska through Pexels.
PAGE 6
2. Salt and heavy metal
accumulation
Salty garden soils, such as those found in arid or marine
environments, can benefit from the addition of salt-tolerant
species. Strawberries (Karakas et al. 2021), peppers (Colla et al.
2006), tomatoes (Albaho and Green 2000; Graifenberg et al.
2003; Green et al. 2000; Karakas et al. 2016), and other
vegetables grown in moderately salty soils may do better when
grown with salt-tolerant companion plants such as Portulaca
oleracea, Salsola soda, and Suaeda salsa (Figure 4). These
plants take up both sodium and chloride, reducing the impact to
less tolerant species.
Just as plants adapted to saline soils can be used to remove
dissolved salts, plants adapted to high levels of toxic heavy
metals (Figure 5) can detoxify, or phytoremediate, soil
contaminated with such chemicals. Such species have been of
great interest to scientists (Rascio and Navari-Izzo 2011), who
suggest that plants hyperaccumulate heavy metals as a defense
mechanism against natural enemies, such as herbivores. While
little research has been published with direct relevance to
gardens and landscapes, we generally understand that many
wetland species, such as Salix and Populus, are
phytoremediators.
3. Volatile organic compounds
(VOCs)
Many plants release aromatic chemicals, also known as volatile
organic compounds (VOCs) and “essential oils,” that are
intercepted by other plants or animals (Figure 6). Some animals,
including pollinators, cats, and humans, find the scents of certain
mints attractive; others are repelled by the odors. Researchers
have identified many of these compounds and found them to be
repellent to insect pests in laboratory experiments (Dieudonné et
al. 2022; Pouët et al. 2021), decreasing feeding behavior and
ultimately the insects’ ability to reproduce and survive (Ameline
et al. 2022; Borges et al. 2022; Dardouri et al. 2021).
Pest-repelling properties of mints and other aromatic species
have long been a staple of popular companion planting wisdom,
but field research has not borne out this belief for mint or any
other aromatic species (Finch et al. 2003; Laffon et al. 2022).
The failure of lab success to translate to practical application is
not surprising: VOCs in the atmosphere dissipate quickly with
increased distance from the plant that releases them. Aromatic
plants in closed systems such as greenhouses (where VOCs
could accumulate) might be useful as pest repellents (Nyalala
and Grout 2007), but gardens and landscapes are unlikely to be
affected.
VOCs are also discussed later in this publication in context of
how they can influence the presence of beneficial and pest insect
species.
Figure 4. Salt-tolerant succulent with ants feeding on nectar. Photo credit:
gordontour through Flickr.
Figure 5. Many wetland species, such as Salix hastata, are aesthetically
appealing as well as useful in absorbing heavy metals. Photo credit: Maja Dumat
through Flickr.
PAGE 7
Figure 6. Common garden plants that produce essential oils: peppermint (top
left), rosemary (bottom left), garlic (right). Photo credits: (top left) wonderferret
through Flickr; (bottom left) Loadmaster (David R. Tribble) through Wikimedia;
(right) Jozefsu through Wikimedia.
Biological Alterations
1. Enhance biodiversity
The biggest change that additional plant species bring to a
garden or landscape is an immediate increase in plant diversity.
While the addition of only one companion plant may not have a
positive outcome in reducing a particular pest, multiple
companion species increase the odds of successful pest control
(Sutter et al. 2022). Increased plant diversity attracts more
herbivores, which in turn attract other species that eat or
parasitize them: this creates a more complex food web. A
complex food web is more resilient than a simple one (Figure 7);
it can more easily tolerate and recover from disruptions.
PAGE 8
Figure 7. Simple and complex food webs. A simple food web will be seriously
disrupted by the removal of any one of its components (top). A more complex
food web is better able to tolerate removal of some components (bottom).
Image credits: (top) courtesy of Wikimedia; (bottom) Siyavula Education
through Flickr.
When more plant species are added to a system, the system
becomes more biodiverse by providing new habitat and
resources for insects, birds, reptiles, mammals, and other plants
(Chalker-Scott 2018, 2015a). The other biological alterations
that companion plants create are all related to improved
biodiversity.
2. Attract and support beneficial
insects and birds
• Provide alternative food and shelter for generalist predator
insects and parasitoids (Balzan 2017; Hatt et al. 2019;
Saldanha et al. 2019; Wang et al. 2020). These “insectary
plants” support beneficial insects such as hoverflies
(Gospodarek 2021), lady beetles (Gospodarek 2021; Wang
et al. 2020), and predatory bugs (Chailleux et al. 2022;
Zuma et al. 2022).
• Improve yield and quality of crops such as strawberry by
attracting additional pollinators (Griffiths-Lee et al. 2020).
• Provide habitat for predacious insects (Gontijo et al. 2018)
and insectivorous birds through addition of vertically
structured landscapes (Figure 8; Chalker-Scott 2015a).
Figure 8. This structurally diverse landscape provides habitat for beneficial
species. Photo credit: Linda Chalker-Scott.
3. Reduce plant damage by
repelling or disrupting the
behavior of harmful insects
Probably the best-known example of repellent companion
planting is the use of French marigolds (Tagetes patula) in
annual beds and vegetable gardens. While this species has been
found to have a negative effect on pests such as codling moths, it
also discourages the moths’ natural enemies and other beneficial
insects (Laffon et al. 2022). These marigolds do not distinguish
between pest and beneficial insect species.
To improve our understanding of repellent species, researchers
have proposed the “disruptive crop hypothesis” which states that
the presence of nonhost plants in a given area disrupts the ability
of specialist herbivorous insects to discover their appropriate
PAGE 9
host plants for feeding or egg-laying (Mansion-Vaquie et al.
2020). Insects spend more time searching for their host, and as a
result, spend less time on host plants overall when their search is
disrupted, all the while consuming valuable metabolic resources
without feeding or reproducing.
The disruptive crop hypothesis seems to support the idea that
VOCs can attract or repel pests—but field research indicates that
neither aroma nor taste influences the ability of herbivorous
insects to find their host (Finch and Collier 2012; Finch et al.
2003). Instead, it is the presence of green objects—nonhost
leaves or otherwise—that disrupts host searching (Figure 9).
Insects seek out green surfaces on which to land and at that point
rely on the smell of plant chemicals to verify their choice (Finch
and Collier 2012, 2000; Nottingham 1988).
Figure 9. A selection of sticky cards that can attract and trap herbivorous
insects. Screenshot captured from amazon.com/green+sticky+cards.
A concept called “push-pull intercropping” suggests that crops
can be interplanted such that one nonhost species repels (or
pushes) the pest insect while another attracts (or pulls) the pest,
leaving the host species less damaged. However, insects are not
repelled from landing on nonhost plants nor do VOC-emitting
“trap crops” attract insects more than five meters away (Finch
and Collier 2012). Instead, research suggests that the number of
green objects surrounding the host plants is the major factor that
prevents insect pests from finding their host plants (Collier and
Finch 2003). The visual miscues provided by nonhost plants
force insects to choose between appropriate (host) and
inappropriate (nonhost) leaves on which to land: for
intercropping to be effective, insects must land on the nonhost
plants (Finch and Collier 2012). Thus, perimeter plantings of
nonhost plants around crops are less effective with increased
distance from the perimeter (Conboy et al. 2019), but
intercropped rows can be effective (George et al. 2019).
Many pest insects not only damage crops directly but carry
bacterial, fungal, and viral diseases. Intercropping susceptible
crop plants with nonhost plants has been found to reduce the
spread of aphid-borne viruses (Waweru et al. 2021). Similarly,
organisms associated with protecting pest insects can be lured
away from the host species of concern, leaving the pests open to
predators and parasitoids. An example of this was seen with
apple aphids, who are protected by black garden ants that eat the
honeydew. When bean plants were planted within the orchard,
the ants preferred to visit the bean aphids; apple aphid
populations were nearly eradicated (Pålsson et al. 2020).
Increased biodiversity through companion planting can lead to
unexpected and unwanted results. For instance, providing
additional food resources for lady beetles can reduce their
consumption of aphids (Wang et al. 2020). Likewise,
populations of beneficial parasitoids can be reduced by
companion plants that attract predators of the parasitoids
(Saldanha et al. 2019). Enhanced structural diversity of
vegetation may, in some cases, interfere with the ability of
nonflying predators to reach their prey (Gontijo et al. 2018).
These drawbacks are minimal, however, compared to the
significant reductions in many pest species when gardens and
landscapes are home to a wide diversity of annual, perennial,
and woody plants.
4. Provide mycorrhizal inoculants
and their associated benefits
Increasing research on belowground plant relationships has
revealed that many plants share indirect connections among their
roots, primarily through mycorrhizal relationships (Figure 10).
The benefits of mycorrhizae are well known (Chalker-Scott
2017), and they can colonize woody plants, perennials, grasses,
and even annuals. Once established in a root system,
mycorrhizae provide enhanced uptake of water and nutrients,
and in doing so can improve plant resistance to drought stress
and diseases. The importance of mycorrhizal interconnections in
establishing new plants has long been recognized in ecological
restoration research (McGee 1990). However, many crop plants
have been regarded as nonmycorrhizal until recently.
Conventional agriculture is still dominated by monocultural
crops planted in annually tilled soils. These conditions are not
ideal for mycorrhizae (Chalker-Scott 2017), so it is not
surprising that they are rarely associated with annual crop plants.
When “nonmycorrhizal” crops are intercropped with other
species, they can become mycorrhizal (Kellogg et al. 2021). This
phenomenon may help account for reports that intercropped
species may be more productive in the presence of the
companion plant (Hata et al. 2019) rather than suffering from
increased competition for underground resources.
PAGE 10
Figure 10. Mycorrhizal fungi associated with oak roots. Photo credit: Linda
Chalker-Scott.
Using Evidence-Based
Companion Planting
Strategies in Home
Gardens and Landscapes
• When creating buffer strips, hedgerows, or other plantings
that will act as refuges for beneficial wildlife, select a wide
variety of species. Limiting companion plants to just a few
species can result in little to no biological control activity
(Lérault et al. 2021; Lopez and Liburd 2022).
• Be aware that perennial companion plants will take a year or
two to establish. Thus, their optimum benefits may not be
realized until that time (Montoya et al. 2020). Annual
companion plants should be used if immediate benefits are
desired.
• If you are growing perennial crops, avoid using annual
companion plants that require yearly soil disruption. Crop
growth and yield can be negatively affected (LaMondia et
al. 2002).
• Dense ground covers function as living mulches and will
reduce weeds (Breitenmoser et al. 2022). To reduce possible
competition with other plants, use living mulches on
pathways, between rows in vegetable gardens and orchards,
and other locations that are not densely planted. Living
mulches play a crucial role in protecting soil from erosion as
well as biological and chemical degradation, and this
improvement may outweigh any drawbacks from
competition (Adamczewska-Sowińska et al. 2022).
• To reduce competition among desirable plants, choose
species whose roots are less likely to interfere with one
another. Intersperse large taproot vegetables like carrots and
radishes with those whose root systems are shallow and
widespread, like corn, onions, and lettuces.
• To reduce possible predation among beneficial insects (such
as lady beetles), use a wide variety of companion plants that
will provide floral resources as a supplemental food source
for predacious insects (Liang et al. 2022).
• Do not use invasive species or even aggressive native
plants. Some companion plants can be overly competitive
for other resources like sunlight, resulting in reduced growth
and vigor of other species (Urli et al. 2020).
• Use nitrogen-fixing species to improve overall soil
microbiome health and reduce the need for nitrogen
fertilizers (Akinnifesi et al. 2010).
• Experiment with different densities of species to determine
satisfactory yields from each (Gospodarek 2021).
• Be cautious when using strong water sprays on plants, as
this can dislodge predatory insects as well as their prey
(Chailleux et al. 2022).
• Avoid using broad-based insecticides, as they will kill pest
predators and parasitoids along with the pest. Proper
companion planting will reduce the need for pesticides in
general (Balmer et al. 2013).
• A well-chosen organic mulch can improve plant growth and
productivity better than the use of nitrogen-fixing
companion plants (Milne et al. 2021). A combination of
organic mulch and companion plants has also been found to
be more effective than companion planting alone (Waiganjo
et al. 2007).
• Use a woody organic mulch, such as arborist wood chips, to
enhance mycorrhizal populations, improve overall soil
health, and control weeds. Arborist wood chip mulches also
house predatory spiders and insects, such as ground beetles
(Chalker-Scott 2015b).
• In vegetable gardens, try to intercrop different species so
that individuals of the same species are as far apart as
possible from each other. This will reduce the ability of pest
insects to infest an entire crop.
• Consider using green cards or other non-plant surfaces to
further confuse herbivorous insects (Martins et al. 2009). Be
aware this will also affect some desirable species, such as
butterflies and moths whose larval life cycle is spent on host
plants.
• Use diverse flowering species around greenhouses to
enhance beneficial species and reduce pest abundance. This
will reduce the likelihood of pests entering the greenhouse
accidentally and reduce the need for insecticide use in the
greenhouse (Li et al. 2020).
• Instead of using wooden planting structures for viny
vegetable and fruit support, consider using live stakes
instead. To keep the stakes at a manageable size, prune them
as needed but leave the prunings as a mulch. Not only will
live stakes enhance your garden’s biodiversity, but the
benefits of the additional mulch can result in substantial
increases in crop yield (Otu and Agboola 1994).
• Consider experimenting with companion plants that have
been identified as having natural insecticidal properties on
specific pests but whose effects on beneficial insects are
unknown (Amoabeng et al. 2019). Do you notice an
increase or decrease in the presence of beneficial insects as
well as pest species? Plants that have negative effects on
PAGE 11
beneficial species would not be good choices for companion
planting (as we have discovered with Tagetes patula earlier
[Laffon et al. 2022]), but a plant that discourages pests
without impacting beneficials would be desirable as a
companion plant.
The Three Sisters
One of the best-known examples of companion planting is the
combination of corn, beans, and squash (often called the “Three
Sisters”). These vegetables provide three different, important
functions to their assemblage: beans are legumes that fix
nitrogen, corn stalks provide physical structure for the beans to
twine around, and squash vines carpet the soil as a living mulch,
keeping the soil cool, moist, and shaded, while suppressing weed
growth. Popular books make claims, without evidence, that “The
Three Sisters produce more food, with less water and fertilizer,
than a similar area planted to any one of these three crops in
isolation” (Hemenway 2001). It is not surprising that the appeal
of the Three Sisters and other companion planting combinations
remains high among gardeners.
Photo courtesy of Wikimedia.
There are few peer-reviewed publications on the practical
benefits of the Three Sisters methodology. Some articles discuss
the history of the practice (Mt. Pleasant and Burt 2010; Ngapo et
al. 2021) and the importance of these crops to Indigenous
peoples (Kapayou et al. 2023). Those that contain experimental
field data comparing monocultures versus polycultures of these
three crops report:
• No significant differences in plant nutrient content
(Kapayou et al. 2023).
• No significant differences in soil characteristics (Kapayou et
al. 2023).
• Reduced yields of beans and squash in polyculture (Mt.
Pleasant and Burt 2010).
• Increased productivity in polyculture using land equivalent
ratios (LER) (Mt. Pleasant and Burt 2010; Zhang et al.
2014).
This last outcome has been used to promote the Three Sisters as
a superior method of producing corn, beans, and squash
together. The figure below explains LER graphically.
Diagram courtesy of Wikimedia.
“The land equivalent ratio is a concept in agriculture that
describes the relative land area required under sole cropping
(monoculture) to produce the same yield as under intercropping
(polyculture)” (Wikipedia 2022).
While this model is mathematically accurate, like any model it
will be altered by local conditions. The yield of the Three Sisters
crops will be different in the hot and dry Southwest than in the
relatively cooler and wetter Northeast. Productivity of each crop
would need to be found before LER could be determined for any
locality. Furthermore, the LER does not take into account the
costs and benefits associated with different cropping systems
(Khanal et al. 2021). It may be a useful model for farmers with
large acreage, but has little practical value in a home garden or
other limited space.
Though there may be historic or cultural reasons for planting a
Three Sisters polyculture vegetable garden, there is no
compelling, published evidence that it benefits plant productivity
or soil quality.
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By
Linda Chalker-Scott, Professor and Extension Specialist, Washington State University
EM128E
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