Soil-Nutrient Interactions Practice Questions
20 free Soil-Nutrient Interactions practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
Soil serves as a source of nutrients for plants mainly by:
- A Providing sunlight
- B Supplying mineral ions
- C Producing atmospheric oxygen
- D Generating heat
Correct answer: Supplying mineral ions
Soil contains essential mineral ions required for plant growth. These nutrients are absorbed by plant roots.
Which form of nitrogen is commonly absorbed by plants from soil?
- A Nitrogen gas
- B Ammonium and nitrate ions
- C Nitric oxide gas emissions
- D Nitrous oxide
Correct answer: Ammonium and nitrate ions
Plants absorb nitrogen mainly as nitrate (NO3-) and ammonium (NH4+) ions. These forms are available in soil.
Soil pH affects plant nutrition by influencing:
- A Light absorption capacity
- B Nutrient availability
- C Photosynthesis rate
- D Respiration
Correct answer: Nutrient availability
Soil pH affects the solubility and availability of nutrients. Extreme pH can limit nutrient uptake.
Which soil type generally retains nutrients best?
- A Sandy soil
- B Rocky soil
- C Gravel soil
- D Clay soils
Correct answer: Clay soils
Clay soil has high cation exchange capacity. It retains nutrients better than sandy soil.
Which process converts atmospheric nitrogen into usable form in soil?
- A Photosynthesis process
- B Respiration
- C Transpiration
- D Nitrogen fixation
Correct answer: Nitrogen fixation
Nitrogen fixation converts atmospheric nitrogen into ammonia. This makes nitrogen available to plants.
Which microorganisms help in nitrogen fixation in soil?
- A Various soil fungi
- B Algae species
- C Rhizobium bacteria
- D Virus particles
Correct answer: Rhizobium bacteria
Rhizobium bacteria fix nitrogen in root nodules of legumes. They convert nitrogen into usable forms.
Which nutrient deficiency is commonly seen in acidic soils?
- A Iron deficiency
- B Excess nitrogen levels
- C Calcium deficiency
- D Potassium excess
Correct answer: Calcium deficiency
Acidic soils often lack calcium availability. This leads to deficiency symptoms in plants.
Which factor affects nutrient uptake by plant roots?
- A Soil aeration
- B Soil pH
- C Water availability
- D All of the above
Correct answer: All of the above
Nutrient uptake depends on multiple factors. Soil aeration, pH, and water availability all influence it.
Which nutrient is mobile in soil and easily leached away?
- A Calcium
- B Iron
- C Nitrogen
- D Phosphorus
Correct answer: Nitrogen
Nitrogen, especially in nitrate form, is highly mobile. It can be easily leached from soil.
Which process involves the movement of nutrients from soil to root surface?
- A Diffusion and mass flow
- B Transpiration flow
- C Photosynthetic activity
- D Cellular respiration
Correct answer: Diffusion and mass flow
Nutrients reach roots by diffusion and mass flow. Water movement helps transport dissolved ions.
Which element is required for chlorophyll synthesis but is not a part of chlorophyll?
- A Iron
- B Magnesium
- C Zinc
- D Calcium
Correct answer: Iron
Iron is essential for chlorophyll synthesis. However, it is not a structural component of chlorophyll.
Which soil condition leads to poor nutrient availability?
- A Neutral pH
- B Balanced moisture
- C Waterlogged soil
- D Proper aeration
Correct answer: Waterlogged soil
Waterlogged soil lacks oxygen. This reduces root respiration and nutrient uptake.
Which nutrient interaction leads to competition between ions?
- A Antagonism
- B Synergism
- C Fixation
- D Assimilation
Correct answer: Antagonism
Antagonism occurs when one nutrient interferes with the uptake of another. This affects plant nutrition.
Which of the following improves soil fertility?
- A Crop rotation
- B Overuse of chemicals
- C Continuous monoculture
- D Soil erosion
Correct answer: Crop rotation
Crop rotation improves soil fertility. It helps maintain nutrient balance and reduces depletion.
Which nutrient is essential for root nodulation in legumes?
- A Nitrogen
- B Phosphorus
- C Sulfur
- D Calcium
Correct answer: Calcium
Calcium is essential for root hair curling and for forming the infection thread that lets Rhizobium bacteria enter root cells and establish nodules; this calcium-dependent signaling step is a key part of legume-rhizobium symbiosis. Nitrogen, phosphorus, and sulfur support general plant growth but are not specifically required for triggering nodule formation.
Which nutrient is least mobile in soil?
- A Nitrogen
- B Potassium
- C Phosphorus
- D Molybdenum
Correct answer: Phosphorus
Phosphorus is relatively immobile in soil. It often remains fixed and less available to plants.
Which factor increases nutrient leaching from soil?
- A High rainfall
- B Low rainfall
- C Low temperature
- D Dry conditions
Correct answer: High rainfall
High rainfall increases leaching. Nutrients are washed away from the root zone.
Which nutrient is required for enzyme activation in plants?
- A Potassium
- B Nitrogen
- C Phosphorus
- D Calcium
Correct answer: Potassium
Potassium activates many enzymes. It plays a role in metabolism and stomatal regulation.
Which soil property helps retain nutrient ions?
- A Soil bulk density
- B Cation exchange capacity
- C Soil drainage capacity
- D Soil parent material composition
Correct answer: Cation exchange capacity
Cation exchange capacity (CEC) measures a soil's ability to hold and exchange positively charged nutrient ions such as potassium, calcium, and magnesium, keeping them from leaching away. Properties like bulk density, drainage capacity, and parent material composition influence soil structure but do not directly determine how well a soil retains these nutrients.
Which of the following best describes soil-plant nutrient interaction?
- A Plants create their own nutrients
- B Soil supplies and regulates nutrient availability
- C Plants grow independently without soil
- D Nutrients are entirely synthesized inside plant leaf tissue
Correct answer: Soil supplies and regulates nutrient availability
Soil supplies essential nutrients and regulates their availability. Plants absorb these nutrients through roots.