Common Weeds Found in Farm


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



A weed is any plant that grows in a place where it is not (expected to grow) wanted



  1. They compete with crops for space
  2. Weeds compete with crops for sunlight
  3. Weeds compete with the crop for nutrient
  4. Weeds harbour crop pests and pathogens
  5. Weeds compete with the crop for soil moisture
  6. It leads to a loss in crop yields
  7. Weeds compete with the crop for soil oxygen
  8. They reduce the quality of crops
  9. They reduce the income of farmers
  10. They cause a reduction in the taste of some grasses
  11. Some weeds are toxic to farm animals



  1. Weeds help in checking soil erosion
  2. Some weeds are useful as food for humans
  3. Some weeds serve as food for animals
  4. Certain weeds have medicinal values
  5. They can be used as green manure
  6. Some are used for making roots, mats and baskets
  7. Weeds are used for mulching
  8. Weeds are used for compost making



  1. What are weeds?
  2. List five beneficial effects of weeds



  1. Production of a large quantity of seeds
  2. Some weeds reduced by seeds
  3. Some weeds reduced by vegetative propagation
  4. Growth of large leaves within a short time
  5. Weeds growth is favoured during the rainy season
  6. Most weeds are wind-pollinated
  7. Production of a large quantity of pollen grains



Most seeds and fruits of weeds are generally dispersed by wind and animals. The mode of dispersal are;

  1. 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.

dandelion-seeds-blowing-in-the-wind-england common weeds in the farm agric science classnotesng

  1. 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.

  1. Dispersal of seeds by water

Water dispersed weeds have waterproof cuticles, air spaces within the fruit and are lightweight

  1. 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.

different seed dispersal common weeds in the farm agric science classnotesng


1. Guinea grass Panicum maximum
2. Bahama grass Cynodon dactylon
3. Carpet grass Axonopus compressus
4. Cogon grass Imperata cylindrica
5. Speargrass Heteropogon contortus
6. Wild sunflower Aspilia Africana
7. Centro Centrosema pubescens
8. Waterleaf Talinum triangulare
9. Wire/sida weed Sida acuta
10. Goat weed Ageratum conyzoides
11. Elephant grass Pennisetum purpureum
12. Giant star grass Cynodon plectostachyum
13. Pigweed Amaranthus spinosus
14. Tridax Tridax procumbens
15. Calapo Calapogonium mucunoides
16. Sunhemp Crotalaria juncea
17. Mucuna Mucuna utilis
18. Stylo Stylosanthes gracilis
19. Northern gamba Andropogon gayanus
20. Southern gamba Andropogon tectorum
21. Puero Pueraria phaseoloides
elephant_grass_common weeds in the farm agric science classnotesng
Elephant Grass
water leaf common weeds in the farm agric science classnotesng
Water Leaf


  1. List and explain different weed dispersal method
  2. 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.

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11 thoughts on “Common Weeds Found in Farm”

    1. There are many factors that can aid the rapid growth of weed either in our environment or anywhere and they are Favorable climate condition, weed species, soil fertility, cropping practices and what have you.

    1. The chemical method of weed control is the use of chemical (herbicides) to eradicate weeds where they are not wanted, this herbicide can be selective or non-selective herbicides.

  1. Aghedo Angela

    People normally say water leaf is a weed when it’s not planted on a farm land , An agricultural scientist once said it affects the growing of other planted crops in the farm land I want to know how , please.

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