Agriculture Reference
In-Depth Information
deals with the interrelationships between all three of
these groups, although it is the plants which are the
focus of horticulturists. Some of these interactions are
explored in Chapter 3.
Although the principles of ecology were developed in
relation to the natural world, they can also be applied
to artificial situations such as gardens. As in nature,
a garden is made up of
population
is of plants and
other organisms that form a
community
occupying
a particular
habitat
. The community together with its
non-living components form an
ecosystem
(p. 36). In
terms of plant choice, it is useful to have a knowledge
of the ecology of a plant's natural habitat, to try to
match this to the environment they experience in
the garden. Suitable levels of temperature, water
and light, soil type and pH need to be considered on
the basis of a plant's origin (Chapter 2). Ecologists
have categorized and described a range of global
geographical zones in which plants grow in the wild
called
biomes
(p. 37) that give a broad idea of a plant's
environmental requirements.
Choice of plant spacing directly relates to the
ecological concept of
competition
between plants
for essential environmental resources such as light,
water and nutrients. Gardeners need to choose
spacings suitable for individual plant species in, for
example, a border, taking into account future growth.
They can also space plants to harness the effects
of competition, or lack of it, for specific purposes
(p. 44).
Plants do not exist in isolation and their
interactions
with other organisms in the community are significant
for the well-being of the whole community. Some of
these organisms might be detrimental to plant health
(e.g. pests and diseases) but many will be beneficial,
such as natural pest predators and those which
recycle nutrients within the garden ecosystem. One of
the most important relationships between all garden
organisms is how they feed on each other. Complex
food chains
and
food webs
(p. 38) exist through
which energy and matter flow and these need to be
kept in balance to support the whole community.
Successful garden management takes account of
these interactions.
The ecological concept of
succession
(p. 40)
describes how plant communities change with time.
Gardeners need to manage this change whether
it is by controlling weeds on a newly prepared plot
or halting succession by interfering with natural
progression through, for example, pruning or
harvesting.
Finally, paying attention to the ecological processes in
gardens and using that knowledge to inform planting
Figure 1.8
A bumble bee feeding on a
Scabeous
fl ower
and management has an added advantage. Gardens
are becoming increasingly recognized as an important
habitat for wildlife
providing suitable habitats for
organisms to feed, shelter and breed. Again, an
understanding of the ecology of gardens helps us to
manage them appropriately to encourage wildlife (see
Figure 1.8), which has also been shown to be good for
our well-being too.
Beyond the garden gate, the importance of protecting
and maintaining ecosystems, both locally and globally,
is recognized because they provide humans with
many useful '
ecosystem services
'. These include
the supply of food, medicines and water, climate and
disease control, nutrient cycling and crop pollination,
flood control and prevention of soil erosion and
also cultural benefits both spiritual and recreational.
Gardeners as well as professional horticulturists,
whether producing food, providing amenity planting
on a large scale or simply growing plants in a
domestic garden, can contribute to maintaining these
ecosystem services through thoughtful design and
management.
Sustainability
There are many ways to define the word
'
sustainable
' but essentially this mean that, if an
action or process is sustainable, it provides the
best for the environment and people, socially and
economically, both now and indefinitely into the
future. Environmental sustainability means making
decisions and taking actions that do not degrade the
natural world irreversibly. The end result of most
environmentally unsustainable practices is
loss of
