Soil Science MCQ Question and Answer | Agriculture MCQ Question

PLFA is Phospholipid fatty acid analysis is used for estimation of microbial biomass and community composition, especially in sediments and soils but also to characterize bacterial communities in water.
Phospholipids can occur in many biological classes such as in plant roots, fungi, as well as in soil bacteria. A sampling of agricultural soils for analysis of chemical composition has long been practiced in crop production and while there has been recognition of the importance of the soil microbial.

With the increase in soil depth, CO₂ content Increases. Carbon dioxide content in soil is about 0.25% while carbon content in the atmosphere is only 0.04%. The soil can store more carbon when it is protected from microbial activity. Gases fill soil pores in the soil structure as water drains or is removed from a soil pore by evaporation or root absorption.

Soil porosity is the percent of total soil volume made up of pore space.
The total porosity is the total void space and as such includes isolated pores and the space occupied by clay-bound water.
$$\eqalign{ & {\text{Total porosity}} = \frac{{{\text{volume of voids}}}}{{{\text{total volume}}}} \times 100\% \cr & = \frac{{1.325}}{{2.65}} \times 100\% \cr & = 50\% \cr} $$

In complex 12-32-16 each granule has all three nutrients i.e. Nitrogen, Phosphorus and Potassium.
NPK 12-32-16 fixes the phosphorus and potassium content in the soil and is highly effective in soils with leaching conditions. It should be applied during sowing and through broadcasting. The dosage should be as per the crop and the soil.

Keys to soil taxonomy came in the year 1990 and developed under the leadership of Dr. Guy Smith. Soil taxonomy is a hierarchical soil classification system with six categories or levels that are order, suborder, great group, subgroup, family and series. It is a morphogenetic soil classification system using diagnostic horizons and features to infer pathways of soil genesis and formation.

Emil Troug, an American Scientist is known as the father of soil testing.
Soil tests may refer to one or more of a wide variety of soil analyses conducted to estimate the plant available concentrations of plant nutrients.
It also helps in determining nutrient content, composition and other characteristics like the acidity or pH level of the soil.

Leghaemoglbin percent in the root nodules of leguminous plants helps in nitrogen fixation by removing oxygen.
Leghaemoglobin is produced as a result of a symbiotic association between bacteroid and plant. The major role of leghaemolglobin involves the protection of nitrogenase enzyme from denaturation, on exposure to the atmospheric concentration of oxygen, thus it helps in the supply of ample amount of oxygen to bacteria for respiration and protects enzyme by removing oxygen from there.

Phenol phosphorodiamidate is most commonly used as a Urease inhibitor.
Urease inhibitors are those chemical compounds that inhibit the functioning of the urease enzyme. The urease enzyme catalyzes the hydrolysis of urea, forming ammonia and carbon dioxide.
These urease inhibitors are used as additives in synthetic urea fertilizer formulations to reduce the loss of fertilizer nitrogen from fields by slowing down the conversion of stable urea to volatile ammonia.

Sodic soils have poor physical conditions.
When the concentration of sodium ions predominates in the soil, it becomes sodic. The pH of sodic soils may be acidic, neutral, or alkaline.
Sodic soils have a very poor structure which limits or prevents water infiltration and drainage. They tend to accumulate certain elements like boron and molybdenum in the root zone that may be toxic to plants.

Press mud is a byproduct of the sugar industry. Press mud is the compressed sugar industry waste produced during the filtration of sugar cane juice.
It serves as a good source of fertilizer. Sugar mills in India produce about 12 million tons of press mud as waste from the double sulphitation process.