Agriculture Reference
In-Depth Information
2
1
Figure 1.11
Plastics waste at a nursery
Figure 1.12
Encephalartos ferox
protected to some extent by CITES (Convention on
Trade in Endangered Species) which monitors and
issues quotas for imports and exports of threatened
species. CITES produces a checklist which can be
downloaded from its website, most of the plants
listed are orchids, cacti, cycads (Figure 1.12), some
succulents and some carnivorous plants.
'greenhouse gas' emissions incurred in their production
and supply. Fossil fuels are used directly for cultivation,
heating and transport of produce and plants. They
are also used indirectly to supply energy for lighting,
refrigeration, water treatment and manufacture of
materials such as plastics, fertilizers and pesticides.
Issues such as the sale of all-year-round produce which
involves heating and lighting in winter and long distance
transport ('air' and 'road miles') are all hotly debated.
Growers can reduce their 'carbon footprint' by reducing
their energy use or using alternative 'green' energy. For
example, combined heat and power generated from
green waste can be used for tomato production in the
winter and wood chip burners are used by
Alstromeria
growers to heat their greenhouses in areas where gas
is not readily available. Some major greenhouses are
located beside power stations to make use of 'waste'
heat. A new greenhouse production area generates all
its energy from crop waste and exports the remainder
to the National Grid. A successful scheme in Suffolk
uses 'waste' carbon dioxide produced in an adjacent
factory to boost photosynthesis (see p. 113) in its
greenhouse-grown tomatoes, thus reducing the amount
lost to the atmosphere.
Waste
is an issue because of the damage to the
environment from landfill and the energy used
to collect, dispose of and recycle it. Horticulture
uses many types of plastic from trays and pots
(see Figure 1.11) to the polythene used to cover
polytunnels, fleece to insulate crops and packaging for
sale of fruits and vegetables, cut flowers and plants.
Growing also generates green wastes such as plant
material, including unsaleable produce which is not
harvested, and composts.
Removal of rare species from the wild
is a result
of our demand for new and ever more interesting
plants. In particular, overcollection of wild bulbs has
been an issue in recent years. Many of these are now
Sustainable gardening practices
Gardeners can help reduce their environmental impact
in many ways including the following:
X
Cut down on water
use by planting drought-
tolerant plants and mulching (see p. 160). Use
rainwater to water plants (purifi cation of mains
water is energy intensive) or reuse household
water where appropriate. Water only when
necessary and do this effi ciently, that is, thoroughly
and less frequently (see Chapter 12).
X
Reduce energy use
by, for example, heating and
lighting in glasshouses or power tools such as air
blowers outdoors. Insulate greenhouses as an
alternative to heating. Source garden materials and
plants locally if possible to reduce fossil fuels used
in transport.
X
Limit the use of fertilizers, pesticides
and other
garden chemicals and use manures correctly.
Only treat pests and diseases when necessary
and follow the instructions carefully using only
approved products. Incorrect and excessive use
might kill benefi cial insects and pollute soil, ponds
and groundwater.
X
Waste management
- good practice can be
summarized as
Reduce
,
Reuse
,
Recycle
.
Z
Reducing waste
is the most sustainable
approach to waste
management - for
example
, by avoiding excessive packaging.
Z
Reuse
items such as plastic pots and trays
(Figure 1.11), which should be thoroughly
