Soil Science MCQ Question and Answer | Agriculture MCQ Question

Rhizobium lupini belongs to the Lupine group of crops as this was isolated from lupine nodules. Lupine is the genus of 200 species of herbaceous and woody plants.
Rhizobium trifoli belongs to Trifolium (clover) group of crops. It is the microsymbiont of Trifolium species, which are valuable agricultural forage legumes.
Rhizobium japonicum is a species of legumes-root nodulating, microsymbiotic nitrogen-fixing bacteria. It is associated with soybean species.
Rhizobium meliloti is found in association with alfa alfa crop plantation. These are aerobic, gram-negative, and diazotrophic species of bacteria. It fixes atmospheric nitrogen into ammonia for their legume symbionts, such as alfa-alfa.

Urea is a source of nitrogen, an essential nutrient crucial for crop growth and development. It is a widely used nitrogenous fertilizer because of its high N content is 46%.
It contains 46% nitrogen. It is the most widely used fertilizer in the country and is good for crop growth and development.

The effective particle diameter for Ion exchange is < 20μ.
Ion exchange is a reversible chemical reaction wherein an ion (an atom or a molecule that has lost or gained an electron and thus acquired an electrical charge) from a wastewater solution is exchanged for a similarly charged ion attached to an immobile solid particle.

Photorespiration is a respiratory process in many higher plants by which they take up oxygen in the light and give out some carbon dioxide, contrary to the general pattern of photosynthesis.
In photorespiration, peroxisomal glutamate: glyoxylate aminotransferase (GGAT) catalyzes the reaction of glutamate and glyoxylate to produce 2-oxoglutarate and glycine.
Amino acids produced during photo respiration are Glycine.

Water-logged soil condition is suitable for denitrification.
When oxygen is limited as in waterlogged conditions, some bacteria use nitrate to support respiration. Thus, denitrification occurs in anaerobic conditions with the presence of denitrifying microorganisms, soluble C compounds and oxidized forms of N.

From the top 25% of effective root zone depth, 40% of total water extraction takes place by roots.
The amount of water that a crop can extract from its root zone and its magnitude depending on the type of soil and the rooting depth.
As a rule of thumb about 70% of the moisture extracted by the root is obtained in the top half of the root zone, about 20% from the third quarter and about 10% from the soil in the deepest quarter of the root zone.

Aromaticity is the property of conjugated cycloalkenes whose primary function is to enhance the stability of the corresponding organic compound. The aromaticity of the compound is mainly because of the delocalizing ability of electrons present in pi orbitals.
Aromaticity is observed to be highest in Humin. Humin is a carbon-based macromolecular substance.

Wind-blown materials, comprised primarily of silt with some fine sand and clay, are called Loess. It is a fine layer rich in mineral material.
Loess is periglacial or aeolian sediment, defined as an accumulation of 20% or less of clay and a balance of roughly equal parts sand and silt, often loosely cemented by calcium carbonate. It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs.

The area (Mha) under physical degradation (Waterlogged) in India is 11.6.
6.41 Mha is degraded land due to water logging and the remaining 4.75 Mha is under sub-surface waterlogging.
Water logging occurs when the soil profile or the root zone of a plant becomes saturated. In rain-fed situations, this happens when more rain falls than the soil absorb or the atmosphere can evaporate.

Boron is extracted with a pressurized and conventional boiling hot water extraction method. this method is inexpensive and rapid to predict Boron availability in arid soils.
The easily hydrolyzable and oxidizable fractions of organic nitrogen present in a soil sample can be extracted using alkaline KMnO₄, which is a mild oxidizing agent. In this method, a known amount of soil sample is boiled with a measured quantity of alkaline KMnO₄.
Total Sulphur in soils was determined by the method of Steinbergs and soluble sulphate by extraction with 0.15% calcium chloride. Since calcium is the primary cation on the adsorbed complex of soils, the CaCl₂ solution is better able to extract other absorbed cations than would solutions containing other cations.