Welcome to SS2 Third Term!
We are eager to have you join us in class!!
In today’s class, We will be discussing Common Weed found in Farm. We hope you enjoy the class!
- Meaning of Weeds
- Effects of weeds on crops and the Economy
- Various types of weeds and their botanical names
- Methods of weed control
MEANING OF WEEDS
A weed is any plant that grows in a place where it is not (expected to grow) wanted
ECONOMIC IMPORTANCE OF WEEDS
- They compete with crops for space
- Weeds compete with crops for sunlight
- Weeds compete with the crop for nutrient
- Weeds harbour crop pests and pathogens
- Weeds compete with the crop for soil moisture
- It leads to a loss in crop yields
- Weeds compete with the crop for soil oxygen
- They reduce the quality of crops
- They reduce the income of farmers
- They cause a reduction in the taste of some grasses
- Some weeds are toxic to farm animals
BENEFITS OF WEEDS TO FARMERS
- Weeds help in checking soil erosion
- Some weeds are useful as food for humans
- Some weeds serve as food for animals
- Certain weeds have medicinal values
- They can be used as green manure
- Some are used for making roots, mats and baskets
- Weeds are used for mulching
- Weeds are used for compost making
- What are weeds?
- List five beneficial effects of weeds
CHARACTERISTICS AND GROWTH HABIT OF WEEDS
- Production of a large quantity of seeds
- Some weeds reduced by seeds
- Some weeds reduced by vegetative propagation
- Growth of large leaves within a short time
- Weeds growth is favoured during the rainy season
- Most weeds are wind-pollinated
- Production of a large quantity of pollen grains
DISPERSAL OF WEED SEEDS AND FRUITS
Most seeds and fruits of weeds are generally dispersed by wind and animals. The mode of dispersal are;
- Dispersal of seeds by wind
Such weeds have feathery, winged or powdery seeds e.g. Tridax (PWD weed), goats weed, guinea grass, elephant grass and many other species of grasses.
- Dispersal of seeds by Animal
Animal dispersed weeds usually have sticky, hooked, edible or colourful fruits or seeds. The sticky and hooked types of fruits and seeds adhere to the coats of grazing animals and are carried from one place to another. Examples of such animals are; rabbits, rats squirrels, antelope and man. Pigweed and commelina spp are examples of such weed.
- Dispersal of seeds by water
Water dispersed weeds have waterproof cuticles, air spaces within the fruit and are lightweight
- Dispersal of seeds by an explosive mechanism
Few plants and all leguminous weeds are dispersed by explosive mechanism eg waterleaf, Centro, Pueraria, Calapo and mucuna.
COMMON WEEDS FOUND ON FARMS
|S/N||COMMON NAME||BOTANICAL NAME|
|1.||Guinea grass||Panicum maximum|
|2.||Bahama grass||Cynodon dactylon|
|3.||Carpet grass||Axonopus compressus|
|4.||Cogon grass||Imperata cylindrica|
|6.||Wild sunflower||Aspilia Africana|
|9.||Wire/sida weed||Sida acuta|
|10.||Goat weed||Ageratum conyzoides|
|11.||Elephant grass||Pennisetum purpureum|
|12.||Giant star grass||Cynodon plectostachyum|
|19.||Northern gamba||Andropogon gayanus|
|20.||Southern gamba||Andropogon tectorum|
- List and explain different weed dispersal method
- List five weeds and their botanical names
We have come to the end of this class. We do hope you enjoyed the class?
Should you have any further question, feel free to ask in the comment section below and trust us to respond as soon as possible.
In our next class, we will be talking about Weed II as we look into the economic importance of weeds. We are very much eager to meet you there.