Alluvial soils vary in nature from sandy loam to clay. They are generally
- A.poor in potash and rich in phosphorus.
- B.poor in both potash and phosphorus.
- C.rich in both potash and phosphorus.
- D.rich in potash and poor in phosphorus.
Correct answer
Explanation
The correct answer is D, rich in potash and poor in phosphorus. Alluvial soils, laid down by rivers, generally contain plenty of potash but lack phosphorus, and they are also often short of nitrogen and humus. They are the most widespread soils of India, covering the Indo-Gangetic-Brahmaputra plains, the river valleys and the eastern coastal deltas. Older alluvium on the higher ground away from rivers is called bhangar and often has kankar nodules, while the newer, finer and more fertile alluvium of the flood plains is called khadar, renewed by floods every year. With fertilisers and irrigation these soils support rice, wheat, sugarcane, pulses and oilseeds. Option A is wrong because it reverses the true position: alluvium is rich in potash, not poor in it. Option B is wrong because these soils are not poor in potash. Option C is wrong because they are not rich in phosphorus, which is usually deficient. Exam tip: alluvial soil = rich in potash, poor in phosphorus; bhangar = old alluvium, khadar = new alluvium.
Practice Questions
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- C.They travel through gaseous, liquid and solid materials.
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Show answer
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