Soil Science - Study Mode

[#151] Dyer's regent is
Correct Answer

(C) 1% citric acid

[#152] Rhizobia is what type of organism?
Correct Answer

(B) Heterotrophic

Explanation

Solution: Rhizobia are heterotrophic soil bacteria with diverse lifestyles. These are aerobic bacteria and are a genus of gram-negative, rod-shaped, nitrogen-fixing bacteria. It can form nodules on legume roots and fix atmospheric nitrogen for the host plant.

[#153] Entropy is highest for which form of matter?
Correct Answer

(C) Gas

Explanation

Solution: Entropy is the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work. The amount of entropy is also a measure of the molecular disorder, or randomness, of a system. Entropy is highest for Gas as because the gas particles move freely, therefore the degree of randomness is the highest.

[#154] Night soil contains
Correct Answer

(D) 5.5% N

Explanation

Solution: Night soil is nothing but Human excreta, collected from cesspools, privies, pail closets, pit latrines, and septic tanks. It was produced as a result of a sanitation system in areas without sewer systems or septic tanks and sold as a fertilizer. Night soil is very rich in essential plant nutrients. It contains about 5.5% Nitrogen, along with other compounds like phosphorus, potassium, etc.

[#155] Leaching requirement when expressed as ratios of
Correct Answer

(D) Both B and C

Explanation

Solution: The concept of 'Leaching requirement' was first developed by the US Salinity Laboratory, California. It has been defined as the fraction of the irrigation water that must be percolated out of the bottom of the root zone to prevent average soil salinity from rising above some level. It can be expressed as EC DW /EC IW as well as Depth of DW/depth of IW . Where, EC = salinity of the soil EC IW = salinity of Irrigation water