Soil is mainly composed of:
a) Minerals, organic matter, water, and air
b) Only minerals
c) Only organic matter
d) Only water and air
Which soil type has the highest water retention capacity?
a) Sandy soil
b) Loamy soil
c) Clay soil
d) Silt soil
Which nutrient is essential for plant root development?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Magnesium
The pH of neutral soil is:
a) 3
b) 5
c) 7
d) 10
Which microorganism helps in nitrogen fixation?
a) Fungi
b) Rhizobium
c) Virus
d) Protozoa
What is the process of removing excess salts from soil called?
a) Aeration
b) Leaching
c) Composting
d) Tilling
Which soil is best suited for agriculture?
a) Sandy soil
b) Loamy soil
c) Clay soil
d) Gravel soil
What is the role of earthworms in soil?
a) Decreasing soil fertility
b) Increasing aeration
c) Absorbing minerals
d) Producing harmful bacteria
Which crop requires acidic soil for better growth?
a) Rice
b) Wheat
c) Sugarcane
d) Cotton
Which soil component improves its water-holding capacity?
a) Sand
b) Humus
c) Gravel
d) Rocks
Which macronutrient is essential for leaf development?
a) Nitrogen
b) Potassium
c) Phosphorus
d) Zinc
Which farming practice prevents soil erosion?
a) Deforestation
b) Crop rotation
c) Overgrazing
d) Excess irrigation
Which element is required for chlorophyll formation in plants?
a) Iron
b) Calcium
c) Sulfur
d) Boron
The process of breaking down organic matter into simpler substances is called:
a) Nitrogen fixation
b) Decomposition
c) Photosynthesis
d) Transpiration
What is the main cause of soil erosion?
a) Overuse of fertilizers
b) Water and wind
c) Plant growth
d) Earthworms
Which nutrient deficiency causes yellowing of leaves?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Calcium
Which type of farming helps in soil conservation?
a) Slash-and-burn
b) Terrace farming
c) Monocropping
d) Deforestation
Which of the following is an organic fertilizer?
a) Urea
b) Compost
c) Ammonium nitrate
d) Superphosphate
Which soil horizon is rich in organic matter?
a) A-horizon
b) B-horizon
c) C-horizon
d) R-horizon
Which practice improves soil fertility naturally?
a) Chemical fertilization
b) Crop rotation
c) Overgrazing
d) Deforestation
Which gas is essential for plant root respiration?
a) Nitrogen
b) Oxygen
c) Carbon dioxide
d) Hydrogen
The presence of which mineral makes soil red in color?
a) Magnesium
b) Iron
c) Phosphorus
d) Potassium
Which soil type is ideal for growing cotton?
a) Black soil
b) Sandy soil
c) Laterite soil
d) Clayey soil
What is the function of mycorrhiza in soil?
a) Improves soil erosion
b) Helps in nutrient absorption
c) Reduces oxygen in soil
d) Increases soil acidity
Which soil nutrient helps in flowering and fruit development?
a) Nitrogen
b) Phosphorus
c) Potassium
d) Calcium
Which soil pH is best for most crops?
a) 4-5
b) 5.5-7.5
c) 8-9
d) 10-11
Which soil component prevents compaction and improves aeration?
a) Clay
b) Silt
c) Sand
d) Humus
What is the role of gypsum in soil?
a) Increases soil acidity
b) Improves soil structure
c) Reduces nitrogen content
d) Prevents plant growth
Which method is used to test soil fertility?
a) Electrical testing
b) Chemical analysis
c) Temperature measurement
d) Visual inspection
Which technique is used for growing crops without soil?
a) Crop rotation
b) Hydroponics
c) Monoculture
d) Plowing
