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प्रश्न
The organic horizon is generally absent from agricultural soils because tilling, e.g., plowing, buries organic matter. Why is an organic horizon generally absent in desert soils?
उत्तर
Organic horizon is generally absent in deserts because of the low content of organic matter due to scarcity of plant and animal remains or excreta.
संबंधित प्रश्न
Read the given statements and select the correct option.
- Hydrophytes possess aerenchyma to support themselves in water.
- Seeds of Viscum are positively photoblastic as they germinate only in presence of light.
- Hygroscopic water is the only soil water available to roots of plants growing in soil as it is present inside the micropores.
- High temperature reduces use of water and solute absorption by roots.
Read the given statements and select the correct option.
- Loamy soil is best suited for plant growth as it contains a mixture of silt, sand, and clay.
- The process of humification is slow in the case of organic remains containing a large amount of lignin and cellulose.
- Capillary water is the only water available to plant roots as it is present inside the micropores.
- Leaves of shade plant have more total chlorophyll per reaction centre, low ratio of chl a and chl b are usually thinner leaves.
The plant of this group are adapted to live partly in water and partly above substratum and free from water
Ophrys an orchid resembling the female of an insect so as to able to get pollinated is due to phenomenon of
In a fresh water environment like pond, rooted autotrophs are
Strong, sharp spines that get attached to animal’s feet are found in the fruits of
Sticky glands of Boerhaavia and Cleome support
Sandy soil is not suitable for cultivation. Explain why?
Describe the mutual relationship between the fig and wasp and comment on the phenomenon that operates in this relationship.
What is thermal stratification? Mention their types.
What is myrmecophily?
Explain Raunkiaer classification in the world’s vegetation based on the temperature.
Explain different types of hydrophytes with examples.
What are the advantages of seed dispersal?
Describe the dispersal of fruit and seeds by animals.
