Soil Science MCQ Question and Answer | Agriculture MCQ Question

The textural triangle describes the relative proportions of sand, silt, and clay in various types of soils. A soil texture triangle is used to classify the texture class of soil. the sides of the soil texture triangle are scaled for the percentages of sand, silt and clay.
The textural triangle that is followed in India is ISSS (Indian Society of Soil Science)

Kaolinite is a clay mineral of the chemical formula Al₂O₃ 2SiO₂ · 2H₂O that has a structure of a 1 : 1 uncharged dioctahedral layer where each layer consists of a single silica tetrahedral sheet and single alumina octahedral sheet.
Under an electron microscope, the shape of Kaolinite is Hexagonal (book-like) and non-idiomorphic crystal forms are associated with rhombohedral blocky alunite.

Beijernick, a Dutch microbiologist and botanist was the one who isolated bacteria from root nodules for the first time.
He discovered new types of bacteria from soil and described biological nitrogen fixation.
He was the first to recognize that viruses are reproducing entities that are different from other organisms.

Indian agriculture is operating at a negative balance of plant nutrients 8 - 10 mt.
The nutrient balance is defined as the difference between the nutrient inputs entering a farming system (mainly livestock manure and fertilizers) and the nutrient outputs leaving the system (the uptake of nutrients for crop and pasture production).
Nutrient balances provide information about environmental pressures. A nutrient deficit (negative value) indicates declining soil fertility.

According to USDA land capability classification, the land is classified under 2 broad groups that are (i) Arable land (cultivable) and (ii) non-arable land (Noncultivable).
Land Capability Classification (LCC) is an exercise for interpretative, grouping, and grading soils according to their potentialities and limitations. It helps to organize significant soil factors for conservation.

Mineralization releases nutrients in soils that are tied up in Organic matter.
Mineralization is the conversion of a nutrient from the organic (i.e. bound to carbon and hydrogen) form to the inorganic form. The process occurs when organic materials, such as soil organic matter, manure, plant residue, or biosolids, are decomposed by soil microorganisms.
Mineralization is the main organic matter conversion process, which leads not only to the preservation of organic matter in the soil but also to its sequestration.

'Hartig net' is seen after infection of Ectomycorrhizae.
Hartig net is a network of inward-growing hyphae that extends into the root penetrating between the epidermis and cortex of ectomycorrhizal plants. This network is a site of nutrient exchange between the fungus and the host plant.
The Hartig net is one of the three components required for ectomycorrhizal roots to form as part of ectomycorrhizal symbiosis with the host tree or plant.

Seeds of pulses are inoculated with bacteria to increase Nitrogen supply.
Pulses belong to the legume family and nitrogen fixation is the main and distinguishing feature of the pulse family.
Nitrogen fixation is the process whereby legume crops and specific rhizobium bacteria associate symbiotically to produce nitrogen from the soil air and make it available to be absorbed and used by the plant.

The occurrence of quartz in high amounts makes a rock Acidic.
Rocks are referred to as acidic if they contain more than 20% of free quartz. It is based on the idea that high silica rocks are acidic whereas the rocks with low silica content are basic.
Typical acidic rocks are granite or rhyolite.

Siderite is a mineral composed of Iron(II) carbonate, the chemical formula of siderite is FeCO₃.
It is valuable iron material, as it contains 48% iron and contains no Sulphur or phosphorus.
It crystallizes in the trigonal crystal system and is rhombohedral in shape, typically with curved and striated faces.