Soil Science MCQ Question and Answer | Agriculture MCQ Question

Physiological Wilt is associated with Osmotic stress.
Wilting of the plants when caused by drought or waterlogged soil is considered physiological wilting.
Osmotic stress leads to efflux or influx of water from or into the cell. It is triggered by water and electrolyte imbalance typically caused by dehydration.
Hyperosmotic stress causes shrinking and hypoosmotic stress causes swelling and ultimately damages the cells of the plants.

Soil test refers to one or more of a wide variety of soil analysis conducted for one of several possible reasons. It analyses soil samples to determine nutritive content, composition and other properties such as acidity, pH, texture, etc.
A soil test should be repeated every 4 yr to assess the nutrient availability and fertility of the soil.

Bronzing is associated with Fe levels greater than 300 ppm in the leaf blade of Rice at tillering. Iron toxicity is a syndrome disorder associated with a large concentration of reduced iron in the soil solution.
Bronzing is restricted to the upper leaf surface and appears as reddish-brown flecking that may uniformly cover the entire leaf surface or parts of it. Affected leaves eventually turn yellow and drop.

Organic manures that have the lowest C/N ratio are Groundnut cake from all the given options whereas compost, FYM, and Biogas slurry are highly rich in C/N ratio.
However, the C/N ratio of any substance is the amount of carbon about the amount of nitrogen present.
Groundnut cake is the residue of oil extraction from groundnut. The NPK ratio of this cake is 7.3 : 1.5 : 1.3 respectively. Its C/N ratio is less in comparison to the other options provided Although it helps in maintaining the C : N ratio in the soil.

VAM (Vesicular Arbuscular Mycorrhizal) is a fungus that can dissolve the phosphates found in abundance in the soil, thus it helps in increasing the available form of phosphates in the soil.
It also makes the plant's disease and pest resistant, also much hardy to resist the harsh weather conditions.

Root growth is particularly affected by the availability of Phosphorus. It helps in encouraging plants to put down a dense collection of new roots and strengthen roots as they develop.
The root is the most important plant part, it serves as the base of any plant, provides anchorage to the plant, along with the absorption of nutrients and water and conduction of these to the stem, also storage of reserve foods. Thus if roots are strong plants can sustain any harsh effects.

Flavonoids and Isoflavonoids are the chemicals responsible for the host-specificity of Rhizobium.
Rhizobium is a genus of gram-negative soil bacteria that fix atmospheric nitrogen. The symbiotic association between rhizobium and legume is a highly specific interaction between the two partners. Host specificity is evident at the early stages of infection and results from multiple interactions involving signaling among bacteria and host plants.

In a muck soil or soil having higher organic matter content, deficiency of Copper (Cu) is encountered first.
A muck soil is usually a peat deposit that has drained and cultivated and in which the surface layer has undergone considerable oxidation and disintegration of the original peat fibres.n it is sapric soil that is naturally waterlogged or artificially drained.

Denitrification is the process that is also known as "Dissimilatory Nitrate Reduction." Which refers to the conversion of nitrate by using it as an electron acceptor.
Denitrification is a microbially facilitated process where nitrate is reduced and ultimately produces molecular nitrogen (N₂) through a series of intermediate gaseous nitrogen oxide products. Complete denitrification serves as an efficient N-removal pathway in the environment.

To prepare 250 mL 0.5N NaOH solution,
$${\text{No}}{\text{.}}\,{\text{of}}\,{\text{moles}}\left( {\text{n}} \right) = \frac{{{\text{Molarity}} \times {\text{V}}\left( {{\text{ml}}} \right)}}{{1000}}$$
Given, volume of the solution = 250 ml
M = 0.5 M
Therefore, No.of moles (n)
$$\eqalign{ & = \frac{{0.5 \times 250}}{{1000}} \cr & = \frac{{125}}{{1000}} \cr & = 0.125{\text{ mol}} \cr} $$
Molar mass of NaOH = 40g
Mass of NaOH required in grams
$$\eqalign{ & = 0.125 \times 40 \cr & = 5\,{\text{g}} \cr} $$