WAEC Agricultural Science questions

291 questions with answers and explanations. Tap an option to check yourself.

1. Question 281· Weeds and weed control· WAEC

   A weed is best described as

   • Aa crop that fails
   • Bany wild plant
   • Ca plant with thorns
   • Da plant growing where it is not wanted

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2. Question 282· Weeds and weed control· WAEC

   A useful feature of some weeds is that they

   • Aharbour pests
   • Breduce crop yields
   • Cserve as food or medicine
   • Dcompete for nutrients

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   Explanation and discussion

3. Question 283· Weeds and weed control· WAEC

   Which of these is a cultural method of weed control?

   • Aspraying herbicides
   • Bmulching
   • Cusing weevils
   • Dburning with chemicals

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   Explanation and discussion

4. Question 284· Weeds and weed control· WAEC

   Some weeds reduce crop quality at harvest by

   • Aadding nitrogen to the soil
   • Bmixing their seeds with the harvested grain
   • Cprotecting crops from pests
   • Dimproving soil structure

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5. Question 285· Weeds and weed control· WAEC

   Spear grass is difficult to control because it

   • Anever produces seeds
   • Bhas no roots
   • Cspreads by underground rhizomes
   • Dgrows only in water

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   Explanation and discussion

6. Question 286· Weeds and weed control· WAEC

   A herbicide that kills only certain kinds of plants is

   • Aselective
   • Bnon-selective
   • Cpre-emergence
   • Da fumigant

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   Explanation and discussion

7. Question 287· Weeds and weed control· WAEC

   Weeds increase the cost of crop production because

   • Athey are sold
   • Bthey add fertiliser
   • Cextra labour or chemicals are needed to control them
   • Dthey protect crops

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   Explanation and discussion

8. Question 288· Weeds and weed control· WAEC

   Guinea grass is regarded as a weed when it

   • Ais fed to cattle
   • Bgrows where it is not wanted in a crop field
   • Cis used for thatching
   • Dgrows in pasture

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9. Question 289· Weeds and weed control· WAEC

   Using a cover crop such as Centrosema helps to

   • Aencourage weeds
   • Bsuppress weeds and protect the soil
   • Cdry the soil
   • Dattract pests

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10. Question 290· Weeds and weed control· WAEC

    Striga (witchweed) is a parasitic weed of

    • Acocoa
    • Bcereals such as sorghum and maize
    • Ccassava
    • Doil palm

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11. Question 291· Weeds and weed control· WAEC

    Spear grass (Imperata cylindrica) is difficult to control mainly because it

    • Aspreads by underground rhizomes
    • Bproduces no seeds
    • Cgrows only in water
    • Dis a parasite

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    Explanation and discussion