Soil Science - Study Mode

[#461] Which of the following condition is suitable for denitrification?
Correct Answer

(A) Water-logged soil

Explanation

Solution: Water-logged soil condition is suitable for denitrification. When oxygen is limited as in waterlogged conditions, some bacteria use nitrate to support respiration. Thus, denitrification occurs in anaerobic conditions with the presence of denitrifying microorganisms, soluble C compounds and oxidized forms of N.

[#462] From top 25% of effective root zone depth how much quantity of total water extraction take place by roots
Correct Answer

(A) 40%

Explanation

Solution: From the top 25% of effective root zone depth, 40% of total water extraction takes place by roots. The amount of water that a crop can extract from its root zone and its magnitude depending on the type of soil and the rooting depth. As a rule of thumb about 70% of the moisture extracted by the root is obtained in the top half of the root zone, about 20% from the third quarter and about 10% from the soil in the deepest quarter of the root zone.

[#463] Aromaticity is highest in
Correct Answer

(C) Humin

Explanation

Solution: Aromaticity is the property of conjugated cycloalkenes whose primary function is to enhance the stability of the corresponding organic compound. The aromaticity of the compound is mainly because of the delocalizing ability of electrons present in pi orbitals. Aromaticity is observed to be highest in Humin. Humin is a carbon-based macromolecular substance.

[#464] Wind blown materials, comprised primarily of silt with some fine sand and clay, are called
Correct Answer

(B) Loess

Explanation

Solution: Wind-blown materials, comprised primarily of silt with some fine sand and clay, are called Loess . It is a fine layer rich in mineral material. Loess is periglacial or aeolian sediment, defined as an accumulation of 20% or less of clay and a balance of roughly equal parts sand and silt, often loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs.

[#465] Area (Mha) under physical degradation (water logged) in india is
Correct Answer

(B) 11.6

Explanation

Solution: The area (Mha) under physical degradation (Waterlogged) in India is 11.6 . 6.41 Mha is degraded land due to water logging and the remaining 4.75 Mha is under sub-surface waterlogging. Water logging occurs when the soil profile or the root zone of a plant becomes saturated. In rain-fed situations, this happens when more rain falls than the soil absorb or the atmosphere can evaporate.