JAMB Agricultural Science questions: Soil fertility, manures and fertilisers

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

1. Question 1· Soil fertility, manures and fertilisers· JAMB

   Liming an acidic soil helps to

   • Aadd nitrogen
   • Blower the soil pH
   • Craise the soil pH
   • Dkill soil organisms

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2. Question 2· Soil fertility, manures and fertilisers· JAMB

   Repeated use of ammonium sulphate fertiliser tends to make the soil

   • Amore alkaline
   • Bmore acidic
   • Csaline
   • Dwaterlogged

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3. Question 3· Soil fertility, manures and fertilisers· JAMB

   Bush fallowing restores soil fertility by

   • Acontinuous cropping
   • Badding chemical fertiliser
   • Cburning crop residues every year
   • Dletting natural vegetation add organic matter over time

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4. Question 4· Soil fertility, manures and fertilisers· JAMB

   A bag of NPK 15:15:15 fertiliser contains

   • A15 kg of nitrogen only
   • Bnitrogen and phosphorus only
   • C15 different nutrients
   • Dequal percentages of nitrogen, phosphorus and potassium

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5. Question 5· Soil fertility, manures and fertilisers· JAMB

   Which of the following is an organic manure?

   • AUrea
   • BSingle superphosphate
   • CFarmyard manure
   • DMuriate of potash

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6. Question 6· Soil fertility, manures and fertilisers· JAMB

   Growing legumes in a rotation improves soil fertility because legumes

   • Ahave deep roots that loosen soil
   • Badd phosphorus to the soil
   • Cprevent all weeds
   • Dfix atmospheric nitrogen through bacteria in their root nodules

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7. Question 7· Soil fertility, manures and fertilisers· JAMB

   Green manuring involves

   • Aapplying urea
   • Bspreading animal dung
   • Cploughing in a growing crop, usually a legume, to enrich the soil
   • Dburning crop residues

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8. Question 8· Soil fertility, manures and fertilisers· JAMB

   Compost is made by

   • Aallowing plant and animal wastes to decompose in a heap or pit
   • Bmixing fertilisers with sand
   • Cburning crop residues
   • Ddrying animal dung in the sun

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9. Question 9· Soil fertility, manures and fertilisers· JAMB

   Placing fertiliser in a band beside the crop row is

   • Afoliar application
   • Bbroadcasting
   • Cside placement
   • Dtop dressing by air

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10. Question 10· Soil fertility, manures and fertilisers· JAMB

    Applying too much nitrogen fertiliser to maize can cause

    • Aseed dormancy
    • Bearly maturity always
    • Cno growth
    • Dlodging and excessive leafy growth

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11. Question 11· Soil fertility, manures and fertilisers· JAMB

    The nutrient mostly responsible for vigorous leafy, green growth in crops is

    • Anitrogen
    • Bpotassium
    • Cphosphorus
    • Dcalcium

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12. Question 12· Soil fertility, manures and fertilisers· JAMB

    An NPK fertiliser labelled 20:10:10 contains

    • A20% nitrogen, 10% P₂O₅ and 10% K₂O
    • B20% potassium
    • Cequal NPK
    • Dno nitrogen

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13. Question 13· Soil fertility, manures and fertilisers· JAMB

    The conversion of ammonium compounds to nitrates by soil bacteria is

    • Anitrification
    • Bdenitrification
    • Cnitrogen fixation
    • Dammonification

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14. Question 14· Soil fertility, manures and fertilisers· JAMB

    Leguminous crops improve soil fertility by

    • Aremoving nitrogen
    • Bfixing atmospheric nitrogen through root nodule bacteria
    • Cadding potassium only
    • Draising soil temperature

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15. Question 15· Soil fertility, manures and fertilisers· JAMB

    Leaching is the

    • Aburning of vegetation
    • Baddition of nutrients
    • Cwashing down of soluble nutrients below the root zone
    • Dcompaction of soil

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16. Question 16· Soil fertility, manures and fertilisers· JAMB

    Phosphorus is needed by crops mainly for

    • Agreen leaf colour only
    • Broot development and seed formation
    • Cabsorbing water
    • Ddrought resistance only

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17. Question 17· Soil fertility, manures and fertilisers· JAMB

    Deficiency of nitrogen in crops is shown by

    • Apurple leaves only
    • Byellowing of older leaves and stunted growth
    • Cleaf scorch at the margins only
    • Dexcessive vegetative growth

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18. Question 18· Soil fertility, manures and fertilisers· JAMB

    Potassium deficiency in plants is shown by

    • Adeep roots
    • Bdark green leaves
    • Cfast growth
    • Dscorching of leaf margins

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19. Question 19· Soil fertility, manures and fertilisers· JAMB

    Potassium deficiency in crops shows mainly as

    • Ascorching of leaf margins
    • Bpurple colouring of leaves
    • Cstunted roots only
    • Ddark green leaves

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20. Question 20· Soil fertility, manures and fertilisers· JAMB

    Which of these fertilisers supplies only nitrogen?

    • Asingle superphosphate
    • Burea
    • Cmuriate of potash
    • DNPK 20:10:10

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