Soil Science MCQ Question and Answer | Agriculture MCQ Question

Bentonite is a mineral having wall-building property, thus used in drilling oil wells. The bentonite in the flush fluid lubricates and cools the cutting tools while protecting against corrosion. As the drilling fluid generates hydrostatic pressure in the borehole, it hinders fluid and gas penetration.

The chlorites are a group of phyllosilicate minerals common in low-grade metamorphic rocks and altered igneous rocks. Chlorite forms blue-green crystals resembling mica.
The general formula for chlorite is (Mg, Fe)₃(Si, Al)₄O₁₀(OH)₂·(Mg, Fe)₃(OH)₆. This formula emphasizes the structure of the group, as TOTO, and consists of alternating TOT layers and O layers. It is a 2 : 2 type.

The lithosphere is the rigid, outermost shell, rocky part of our earth. It is composed of the crust and the portion of the upper mantle. It extends to a depth of about 60 miles. It is broken into about a dozen separate, rigid blocks, or plates.
The lithosphere is mainly made up of Igneous rocks, made up by the cooling of magma.

Water at wilting coefficient is held with a force of 15 atm (atmospheres). The wilting coefficient of soil water is defined as the percentage water content of a soil when the plants growing in that soil are first reduced to a wilted condition from which they cannot recover in an approximately saturated atmosphere without the addition of water to the soil.

Legumes are the plants that form roots nodules in association with the rhizobium bacteria. The free-living soil bacteria grows near the roots of the legumes and is unable to fix nitrogen in a free condition.
The formation of nodules is more sensitive to soil acidity than other aspects of plants. Legumes fail to develop nodules if pH is less than 5.

Soil organic matter is the organic component of soil, consisting of three primary parts including small fresh plant residues and small living soil organisms, decomposing (active) organic matter and stable organic matter (humus).
Humin is the insoluble component of soil organic matter. It is a carbon-based macromolecular substance. Humins make up about 50% of the organic matter in the soil.

Muck is sapric soil that is naturally waterlogged or artificially drained. These soils are deep, dark coloured, and friable. Muck soil is used for growing specialty crops such as onion, carrots, celery and potatoes.
Muck soil contains about 20 - 50% organic matter. Muck farming on drained swamps is an important part of agriculture.

The connotation of ‘Fol’ (Folia, leaf) formative is the Mass of leaves.
This is one of the types of Sub order out of 47 sub-order of the soils, the sub-order indicates genetic homogeneity. Climatic environment, vegetation and wetness help in determining the genetic processes.

The “Von Bemmelen factor” is based on the assumption that organic matter contains 58% of organic carbon. The literature indicates that the proportion of organic C in soil organic matter for a range of soils is highly variable.
The value of the Von Bemmelen factor is 1.724.

Puddled soil is the soil in which the structure has been destroyed by the physical impact of raindrops, tillage when wet, or trampling by animals.
Puddled soil comes under the massive grade of soil structure. Puddling of some heavy–textured soils leads to an increase in total soil volume and a decrease in bulk density.