Soil Science MCQ Question and Answer | Agriculture MCQ Question

A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum temperature of 35°C. these organisms play important role in the decomposition of organic matter and the mineralization of nutrients. Bacteria such as mesophiles are used in cheese making due to their role in fermentation.

Among the following Iodine is not a Beneficial element.
There are 17 essential elements for the growth and development of plants and iodine is not one of them. However, Iodine influences plant growth and development and can modulate the plant transcriptome. It exerts a beneficial effect on plants, even when used in tiny amounts.

The excreta of earthworms generally have 25% of calcium. It contains NKP, micronutrients, beneficial soil microbes also plant growth hormones and enzymes.
The excreta of the earthworm is known as vermicompost and is the product of the decomposition process using various species of worms.
Vermicompost contains water-soluble nutrients and is an excellent, nutrient-rich organic fertilizer and soil conditioner. It is used in gardening and sustainable, organic farming.

Nutrients that affect growing tips most are Calcium and Boron.
Plants responding to calcium deficiency exhibit discolouration and upward rolling of leaves and ultimately necrosis. Whereas Boron deficiency exhibit minor chlorosis, upward curling, thickening of leaves, distorted meristems and strap-like leaves.

Plants absorb nutrients mostly through Roots.
Plants take up essential elements from the soil through their roots. Nutrient uptake in the soil is achieved by cation exchange, where root hairs pump hydrogen ions into the soil through proton pumps. These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root.

Nitrogenase is the enzyme responsible for breaking down the N ≡ N bonds.
It is the enzyme produced by cyanobacteria and rhizobacteria and is responsible for the reduction of nitrogen to ammonia. Nitrogenases are the only family of enzymes known to catalyze this reaction, which is the key step in the process of nitrogen fixation.

The law of the minimum was given by Liebig in 1862.
This law states that the growth is dictated not by total resources available, but by the scarcest resource which is also referred to as a limiting factor. It was found that increasing the number of plentiful nutrients did not increase the plant growth, only by increasing the amount of the limiting nutrient, did the growth of the crop was improved.

Most of the microorganisms function at their best within the neutral pH range i.e. of 6.0 - 7.5. The pH is important for the proper functioning of organisms as the enzymes that catalyze the chemical reactions of life require a specific pH to function. Moreover, the increase and decrease in pH can cause denaturation of biochemical like proteins and make them non-functional, resulting in cell death.

Azomethine H is a colorimetric reagent for the determination and detection of Boron.
It forms an orange complex with boron in an aqueous solution. The molar absorptivity of this complex is 1.01 × 10⁴ at 415 nm which can be further detected in the range of 1 - 6 micrograms per ml.

Entisols are the young soils with no horizon. These are the most abundant soil order, occupying about 16% of the global ice-free land area.

Vertisols are clay-rich soil. The high content of clay minerals shrinks and swells as they change water content.

Spodosols are acid soils with the leached upper horizon and are characterized by an accumulation of humus that is complexed with aluminium and Iron.

Oxisol is highly weathered tropical and subtropical soil. These are found primarily in the intertropical regions of the world.