Soil Science MCQ Question and Answer | Agriculture MCQ Question

The vertical section of the soil that depicts all of its horizons is known as the Soil Profile.
The soil profile extends from the soil surface to the parent rock material. It allows for examining the structure of the soil. A soil profile is divided into layers which are termed Soil horizons. The main soil horizons are A, B, C, D, E and O.

The total mean mass of the atmosphere is 5.1480 × 1018 kg with an annual range due to water vapour of 1.2 or 1.5 × 1015 kg depending on whether surface pressure or water vapour data.
50% of the atmospheric mass lies within 5.6 km from the earth’s surface.
About 80% of the total mass lies in the troposphere which is the lowest layer of our atmosphere.

Ingenious rocks which are formed on the surface of the Earth by the crystallization of magma are called Extrusive rocks. These are fine-grained textures because their rapid cooling at or near the surface did not provide enough time for large crystals to grow.
Some examples of extrusive rocks are Basalt, Rhyolite and Andesite.

CEC of Vermiculite is the highest of the given options and it is about 120 - 150 cmol/kg.
CEC (cation exchange capacity) is the measure of its ability to absorb cations from the solution. It has been defined as the number of cations that are available at a given pH for exchange with other cations.
Vermiculite is the name of a group of hydrated laminar minerals (aluminum-iron magnesium silicates) that look like mica. It is a hydrous phyllosilicate mineral that undergoes significant expansion when heated.

The carbon to nitrogen ratio is a ratio of the mass of carbon to the mass of nitrogen in a substance.
Sawdust is the by-product of woodworking operations composed of small chippings of wood.
The C : N ratio of saw dust is 225 : 1.

The most electronegative element of the periodic table is Flourine. Its electronegativity value is 3.98.
Electronegativity is a chemical property that describes the tendency of an atom or a functional group to attract electrons toward itself. It is affected by both its atomic number and the distance that its valence electrons reside from the charged nuclei.

In remote sensing, Infrared radiation is utilized for photography. The wavelength used for photography range from about 700 nm to about 900 nm.
Remote sensing is the process of detecting and monitoring the physical characteristics of an area by measuring it's reflected and emitted radiation at a distance. Special cameras collect remotely sensed images, that help researchers “sense” things about the Earth.

True soil is composed of mineral and organic particles in adequate proportions for the growth and development of plants.
The inorganic particles present in the soil originated from the process of weathering of rocks, i.e. continuous degradation of the rocks.
Large quantities of soil colloids are the finer size fractions of the soil i.e. clay and organic matter that makes the soil sticky.
The formation of the thinner soil leads to a steeper slope because the soil tends to be washed down the slopes by the rain from the slopes.

If any rock contains Iron (Fe), Manganese (Mn) and Sulphur (S) then both the reactions like Oxidation and Reduction can be seen in such rocks. It causes chemical alterations in the rocks.
Oxidation is the reaction of rock minerals with oxygen to make them resistant to weathering by causing rusting.
Reduction of the rocks is the process of removal of oxygen, which mostly occurs in the waterlogged condition where there is less oxygen available.

1N NH₄ OAC (ammonium acetate) is the extract used for the determination of CEC, Cation exchange capacity.
In this method, the soil is leached with an excess of neutral, in 1 N ammonium acetate solution to remove the exchangeable cations and to saturate the exchange material with ammonium. Sodium is a saturated cation and is moved by an ammonium cation. The CEC is calculated based on the concentration of sodium ions in the extract.