Agriculture Reference
In-Depth Information
Managing a garden for wildlife will help to conserve
biodiversity both in the garden itself and in the wider
area (see Chapter 3). See 'Sustainable Gardening' on
the companion website.
Organic gardening
There are many different ways of gardening that
make use of the principles of horticulture outlined
in the following chapters. One particular philosophy
of growing that demonstrates the wide range of
approaches is that of growing 'organically'. Most
of the topic deals with the nature of plants and
soils common to all growers, but those growing
'organically' will focus on some specific parts of the
text and not make use of others such as the use of
artificial fertilizers and pesticides. The degree to which
the gardener adopts an 'organic' approach can range
from the strict adherence to the 'organic' philosophy
to those who are just inclined to 'no chemicals' but are
less concerned about obtaining organically acceptable
plants, propagation material, manures and so on.
Organic gardeners
view their activities as an
integrated whole and try to establish a sustainable
way forward by conserving non-renewable resources
and eliminating a reliance on external inputs. The soil
is managed with as little disturbance as possible to
the balance of organisms present. Organic growers
maintain
soil fertility
by the incorporation of animal
manures (see p. 163), composted material (see
p. 160) and green manuring (p. 165). The intention is
to ensure plants receive a steady, balanced release
of nutrients through their roots: 'feed the soil,
not the plant'. Besides the release of nutrients by
decomposition (see p. 158), the stimulated earthworm
activity incorporates organic matter improving soil
structure which can eliminate the need for cultivations
(see 'no dig' methods p. 150). Emphasis is placed
on the
balanced nutrition
of the plants because of
its role resisting pests and diseases (p. 192) - for
example, excess nitrogen feed leads to soft growth
that is vulnerable to diseases, strong growing plants
can grow away from pest attacks.
The main cause of an imbalance of soil organisms is
considered to be the use of
quick-release fertilizers
and
pesticides
. The greater number of soil species
(biodiversity) that is encouraged prevents the increase
of pests and diseases. Pests and diseases are
managed 'organically' by this approach along with the
use of resistant cultivars (p. 190), physical barriers,
pesticides derived from plant extracts (p. 203), by
careful rotation of plant species (p. 193) and by the
use of naturally occurring predators and parasites
(p. 195-6). Weeds are controlled by using a range of
Figure 1.13
A range of rocks sold for garden use
cleaned and sterilized before use (see
p. 130), if reducing waste is not possible.
Hard landscaping materials such as slabs,
rocks, building materials and timber can be
reused, which also avoids further damage to
habitats (Figure 1.13). Limestone pavement,
for example, is a natural rock formation which
provides a habitat for many rare species and
was previously used for rock gardens. Although
it is now legally protected in Britain and Ireland,
removal still occurs.
Z
Recycle
items that cannot be reused, although
many horticultural plastics such as seed trays
and polystyrene can only be landfi lled or
incinerated. Garden waste can be composted
at home (see Chapter 13), which avoids energy
being used for collection and disposal as well
as providing a valuable soil improver. Organic
waste in landfi ll produces methane which is
25 times stronger than carbon dioxide as a
greenhouse gas.
X
Timber
for garden structures should be produced
from sustainable sources such as those certifi ed by
the Forestry Stewardship Council (FSC).
X
Peat alternatives
should be used wherever
possible and never use peat as a soil improver or
mulch. If possible, choose plants that have been
grown in peat-free composts.
X
Never collect plants from the wild
and ensure
that purchased plants are sustainably sourced.
X
Check that imported rare plants
have appropriate
CITES certifi cates.
X
Avoid planting invasive species
especially near
or in ponds and waterways.
