Soil Science - Study Mode
[#871] 1 meq of Calcium is how much Ca?
Correct Answer
(A) 20 mg
Explanation
Solution: 1 mEq of calcium = 0.5 mmol of elemental calcium = 20 mg of elemental calcium per mEq. Calcium can be measured by the amount of calcium salt or the amount of the elemental calcium in milligrams, in milliequivalents or millimoles.
[#872] Soil water potential per unit mass is expressed as
Correct Answer
(D) L 2 T -2
Explanation
Solution: Soil water potential is defined as "the amount of work that must be done per unit quantity of pure water to transport reversibly and isothermally to the soil water at a considered point, an infinitesimal quantity of water from a reference pool. Soil water potential is the sum of four different components: gravitational potential + the matric potential + the pressure potential + the osmotic potential. Soil water potential per unit mass is expressed as L 2 T 2 .
[#873] What are the main forces governing the formation of Metamorphic rock?
Correct Answer
(D) Both A and B
Explanation
Solution: Metamorphic rock arises from the transformation of existing rock into new types of rock in a process called metamorphosis. It makes up a large part of the Earth's crust and 12% of the Earth’s land surface. The main forces governing the formation of metamorphic rocks are both Heat and pressure. These rocks are subjected to high heat, high pressure and mineral-rich fluids.
[#874] PO 4 -3 is the principle phosphate anion, when soil pH is
Correct Answer
(C) > 9.0
Explanation
Solution: Phosphate is an anion, salt, functional group, or ester derived from phosphoric acid. The phosphate or orthophosphate ion [PO 4 ] -3 is derived from phosphoric acid by the removal of three protons. At soil pH around or more than 9, [PO 4 ] -3 is the principle phosphate ion available in the soil.
[#875] Which one of the following is an example of natural chelate
Correct Answer
(C) Citric acid
Explanation
Solution: Among the following options, Citric acid is an example of a natural chelate. The natural chelates are very small molecules and consequently pass through the plant's barriers including the cuticle, cell walls and cell membranes maximizing absorption and assimilation. Citric acid had typically been used to control free iron cations in spent HCl solutions by chelating to iron and preventing the precipitation of iron hydroxide or iron sulphide.