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AGR 3102
PRINCIPLES OF WEED SCIENCE
Weeds of Orchards and Plantation Crops
Objective: To study the morphological characteristics and identify weed species found
in orchards and plantations
Materials
A4 papers or sketch book
Specimens (as displayed) and camera (optional)
Introduction
Plantation crops and orchards are commonly big and tall perennial trees. These crops,
when mature, normally have their canopy providing shades to the ground surface.
Weeds in such areas are normally less or non existence because light (important for
plant growth) penetration to the ground is less available. Therefore, in these cropping
areas, weeds can only be found during the early stages of planting and crop growth
(i.e. nursery or young plant plantation), where crops are still relatively small and
ground hasn’t fully covered by the canopy. It is during the early stage of crop growth
where weeds cause a lot of problems through competition, interference and
parasitism, which required high attention and careful management. In addition,
plantation and orchard weeds also grow readily in replanting areas, where sunlight
can penetrate to the ground surface.
Since the plantation and orchard crops are big perennial tress, weeds that often cause
competition problems are also strong woody and/or large herbaceous species.
Sometimes, several small herbaceous, aggressive grasses and creeping plants are also
found. These weeds need to be controlled early throughout the area by circle weeding
around each crop up to 1-2 m diameters.
Laboratory Works
Observe, identify, draw, and record the characteristics and their taxonomic naming for
each specimen on display. Scientific name should comprise of family, genus, and
species. Use this record for later practical.
Questions to Answer
1.
How many species are grasses, sedges, herbaceous or woody plants?
2.
Give examples of orchard crops and plantation crops in Malaysia?
3.
Give the scientific name of some grasses, sedges, herbaceous or woody
weeds?
4.
List all weed species on display that are also used/can be potentially used
as cover crops in plantation?
AGR 3102
PRINCIPLES OF WEED SCIENCE
Weeds of Landscape and Water Bodies
Objective: To study the morphological characteristics and identify weed species found
in landscape and water bodies
Materials
A4 papers or sketch book
Specimens (as displayed) and camera (optional)
Introduction
Weeds are often the most visible landscape pests. And they are a major problem for
homeowners and landscape managers. Weeds are a concern principally because they
compete with desirable plants fro space, light, nutrients, and water. Apart from that,
they also detract from the appearance and function of landscape, which can greatly
reduce the aesthetic value in the infested area such as the beauty and scenery, as well
as causing danger, injury, and hinder recreational activities, etc.
Plants are natural and important components of the aquatic environment. Microscopic
plants (algae) form the base of the aquatic food chain. Larger algae and plants provide
habitat for fish and food organisms, and all plants produce oxygen as they
photosynthesize during the daylight hours. However, excessive growths of these
plants can have a detrimental effect on a body of water and its inhabitants. Many
shallow, nutrient-rich ponds, lakes, and drainage ditches provide ideal conditions for
abundant aquatic weed growth.
Laboratory Works
Observe, identify, draw, and record the characteristics and their taxonomic naming for
each specimen on display. Use this record for later practical. Scientific name should
comprise of family, genus, and species.
Questions to Answer
1.
Name the weeds of landscape areas and aquatic environment, and relate each
species with one obvious observable characteristic.
2.
Are weeds of landscape areas differ from those weeds of the plantation or
orchard?
3.
Some modifications area normally found in aquatic weeds. What are the
modifications which you observed?
AGR 3102
PRINCIPLES OF WEED SCIENCE
Weeds of Field Crops
Objective: To study the morphological characteristics and identify weed species found
in the field/farm
Materials
A4 papers or sketch book
Specimens (as displayed) and camera (optional)
Introduction
There are many weed species which grow in the field/farm areas, competing with the
crops for nutrient, space, water, gasses etc. In fact, in field crops, weeds have a very
vigorous growth, relatively have short-life span, diverse and abundant. This is because
of the nature of the cropping systems which often changes according to the crop
planted. In addition, a short planting period for most of the field crops, which
regularly changes the surrounding environment, further encourages the diversity of
weed growth. As usual, each weed species differs morphologically with others, which
can be used for its identification.
Laboratory Works
Observe, identify, draw and record the characteristics and their taxonomic naming for
each specimen on display. Scientific name should comprise of family, genus, and
species. Use this record for later practical.
Questions to Answer
1. What types of weed are normally found in the field crops?
2. How many families and genus of the field crop weeds are displayed for you to
study and identify?
3. How should the scientific name of a plant be written?