Soil Science MCQ Question and Answer | Agriculture MCQ Question

Tourmaline is the one mineral among the given options that is the main source of boron in soils.
Tourmaline is a crystalline silicate mineral group in which boron is compounded with elements such as aluminum, iron, magnesium, sodium, lithium or potassium.
It occurs as long, slender to thick prismatic and columnar crystals that are usually triangular in cross-section.

Among the following given options, Sulphur is not a micronutrient, whereas copper, zinc and Iron are micronutrients, required in very small amounts by plants for their functioning and growth.
Sulphur is a macronutrient, required in large proportions by plants for adequate growth and development. It is used in the formation of amino acids, proteins, and oils. It is also necessary for chlorophyll formation, promotes nodulation in legumes and helps activate specific enzymes and vitamins.

The neutralizing value is the percentage of the material that can neutralize acid expressed as the calcium carbonate equivalence (CCE) of the product.
The neutralizing values of the following liming materials are such that:
CaO > Ca(OH)₂ > CaMg(CO₃)₂ > CaCO₃
Calcium oxide has the highest value i.e. 178.5, followed by 135 of calcium hydroxide, then 108.5 of calcium magnesium carbonate and lastly 100 of calcium carbonate.

The term Catena was introduced by Geoffrey Milne in 1935.
This term describes the soil topography units and the lateral variation in soils over a hillslope. The concept of a catena was developed to analyze the regular variation of soils across a slope.
A mature catena is in equilibrium as the processes of deposition and erosion are in balance.

Nutrient use efficiency (NUE) shows the ability of crops to take up and utilize nutrients for maximum yields. It involves three major processes in plants: uptake, assimilation, and utilization of nutrients. Nutrient Use Efficiency of Micronutrients is 2% - 5%.
The seven micronutrient elements are boron, zinc, iron, copper, molybdenum, manganese and chlorine.

Gapon’s equation is a widely used equation to describe the CEC of soils. CEC is the cation exchange capacity of the soil and it is a measure of how many cations can be retained on the soil particle surface.
The Gapon exchange equation is commonly used to study binary heterovalent exchange reactions. The Gapon equation help to maintain the ratio of sodium to calcium on the soil colloid surface content.

Halloysite is an aluminosilicate clay mineral with its main constituents as Oxygen, Silicon, and hydrogen. It typically forms by hydrothermal alteration of alumino-silicate minerals.
Halloysite was first described in 1826 and named after the Belgian geologist Omalius d’Halloy.
Layer spacing of Halloysite is 10.25.

Important criteria for classifying soil at the family and suborder levels is the Soil temperature regime.
Soil taxonomy is a hierarchical soil classification system with six categories or levels, theses are order, suborder, great group, subgroup, family and series.
Soil taxonomy is a morphogenetic soil classification system using diagnostic horizons and features to infer pathways of soil genesis and formation.

Ballast elements are those elements that refuse to attribute any useful metabolic function to these elements as they are available in large amounts in plant tissues and the plants can be grown perfectly normally without them.
Aluminium (Al) and Silicon (Si) are such elements that are present in abundance in plants and their absence may not harm the growth of the plants thus called Ballast elements.

Unsaturated hydraulic conductivity refers to a measure of soil water-retaining ability when soil pore space is not saturated with water. And it is maximum in Clayey soil.
In unsaturated soil, some of the pores become air-filled and the conductivity decreases.