Soil Science - Study Mode

[#261] Silica: sesquioxide (R 2 O 3 ) ratio for tropical ecoregion is
Correct Answer

(D) < 2

Explanation

Solution: Sesquioxide ratio is the ratio of the number of molecules of silica to the number of molecules of alumina and iron oxide. The more highly weathered soils or their clay fractions in warm temperate, humid regions and especially those in the tropics, generally have a low ratio. The ratio is < 2 for tropical ecoregion.

[#262] Stokes law, v = kr 2 , value of k in 20°C in aqueous medium is
Correct Answer

(B) 34,700

Explanation

Solution: Strokes law is derived by George Gabriel Strokes in 1851. It is the basis of the falling-sphere in which the fluid is stationary in a vertical glass tube. A sphere of known size and density is allowed to descend through the liquid. Strokes law states that the force that resists the sphere's fall in a viscous fluid is directly proportional to the viscosity of the sphere, the radius of the sphere, and the viscosity of the fluid. The value of k in 20°C in an aqueous medium is 34,700.

[#263] The number of functional plant nutrient is
Correct Answer

(A) 16

Explanation

Solution: The number of functional plant nutrients is 20 . Plants require various nutrients for their growth and development. The essential nutrients for plants can be broadly categorized into macronutrients and micronutrients. Macronutrients are required by plants in relatively large quantities, while micronutrients are needed in smaller amounts. The macronutrients essential for plant growth include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). Additionally, plants require micronutrients such as iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), boron (B), molybdenum (Mo), chlorine (Cl), and nickel (Ni), among others. In total, there are 20 functional plant nutrients that are essential for plant growth and development. Therefore, Option B: 20 is the correct number of functional plant nutrients.

[#264] In India, which fertilizer manufactured first?
Correct Answer

(C) SSP

Explanation

Solution: In India, SSP is the fertilizer that was manufactured first. SSP is single super phosphate and is the first commercial mineral fertilizer and it led to the development of the modern plant nutrient industry. The industry made a very humble beginning in 1906 when the first manufacturing unit of SSP was set up in Ranipet near Chennai with an annual capacity of 6,000MT.

[#265] Micronutrients are analyzed by
Correct Answer

(A) AAS

Explanation

Solution: Micronutrients are analyzed by AAS. AAS (Atomic Absorption Spectrometry) is a laboratory instrument that measures the concentration of microelements in soil, fertilizer and plant sample solutions. It is so sensitive that it can measure down the concentration of elements to parts per billion in any soil sample.