Soil Science MCQ Question and Answer | Agriculture MCQ Question

Diamond is the mineral substance placed at number 10 on Mohs scale.
The Mohs hardness scale was developed in 1822 by Frederich Mohs. This scale is a chart of the relative hardness of the various mineral (1-softest to 10-hardest).
Diamonds also show a variation in hardness (the octahedral faces are harder than the cube faces). Mohs hardness is a measure of the relative hardness and resistance to scratching between minerals.

The term specific gravity refers to the ratio of the density of a solid or liquid to the density of water at 4 degrees Celsius. The term can also refer to the ratio of the density of a gas to the density of dry air at standard temperature and pressure.
The approximate specific gravity of Sulphuric acid (AR grade) is 1.84.

The most widely used source of nitrogen in agriculture in India is Urea.
Urea is a source of nitrogen, an essential nutrient crucial for crop growth and development.
Urea is the most important nitrogenous fertilizer in the country because of its high Nitrogen content i.e. 46%.

CEC is cation exchange capacity is a measure of the soil’s ability to hold positively charged ions.
If the contents of exchangeable ions (cmol kg^-1) determined in soil are
Na⁺ = 5
K⁺ = 5
Ca²⁺ = 10
Mg²⁺ = 2
H⁺ = 1
Al⁺³ = 1
Cl^- = 1.6
HCO^-₃ = 0.4
Summing up all the values of positive ions, we get the value of CEC of soil i.e. 24 cmol (P⁺) kg^-1

The nutrient concentration range in which added nutrients will not increase yield but can increase nutrient concentration is referred to as Luxury consumption.
It is often used to describe nutrient absorption by the plant that does not influence yield. It occurs when soil nutrient levels are above optimum and plants take up more of a nutrient than needed for functioning and production.

The equation introduced by Mitscherlich has been generally used to express nutrient-yield relationships as follows: $${\bf{y = A}}\left( {{\bf{1 - }}{{\bf{e}}^{{\bf{ - eb - ex}}}}} \right)$$
Bray has modified the mitscherlich equation to $${\bf{log}}\left( {{\bf{A - y}}} \right){\bf{ = logA - }}{{\bf{C}}_{\bf{1}}}{\bf{b - cx}}$$
Where A = % theoretical maximum yield, y = actual yield obtained in q ha^-1, b = native soil test value in kg ha^-1, x = fertilizer nutrient applied in kg ha^-1, c₁ and c = constants i.e., the efficiency of soil and fertilizer nutrients respectively.

A soil profile is a vertical section of soil, standard to a depth of 1.5 - 2.0 meters. Most soils have layers, parallel to the soil surface, called horizons. The horizons are the result of soil formation and geological processes.
The soil profile is a cross-section of the soil that reveals its horizons (layers). Soil generally consists of visually and texturally distinct layers, which can be summarised from top to bottom as A, B, C, E and O horizons.

This is the correct answer. Urea-form contains approximately 40% nitrogen (N). Urea-form is a type of nitrogen fertilizer commonly used in agriculture to supply plants with nitrogen, which is an essential nutrient for their growth and development.

Therefore, the correct answer is Option D: 40%. Urea-form contains approximately 40% nitrogen.

In the case of Zn deficiency of paddy, around 25 kg of zinc sulphate should be applied in one hectare of soil or dip roots of rice seedlings in a 2 - 4% zinc sulphate suspension before planting to overcome the deficiency.
Zinc is an essential plant nutrient required for several biochemical processes in the rice plant, including chlorophyll production and membrane integrity.

Ammonium nitrate is a fertilizer that has a risk of fire or even explosion. It exploded abroad on a ship docked near Texas City, Texas in 1947.
It can explode on its own if its temperature is raised to 400 degrees Fahrenheit, as it belongs to a chemical class known as oxidizers.