Soil Science MCQ Question and Answer | Agriculture MCQ Question

Glass electrode can be used for the estimation of soil pH range of 1.0 - 9.0.
A glass electrode is a type of ion-selective electrode made of a doped glass membrane that is sensitive to a specific ion. It is commonly used to measure pH.
Glass electrode with a glass membrane special, chemically pure, soft glass paired with a calomel reference electrode for estimation of soil pH.

FYM is farm yard manure, which is an important organic resource for agricultural production, including compost, cow dung, green manure, etc.
Preparation of FYM (Farmyard manure) by Trench method is given by C. N. Acharya.
In this method trenches of 6 - 8 m in length, 1.5 - 2 m in width, and 1 - 1.25 m in depth are prepared. A mixture of dung and urine-soaked litter is deposited in layers in these trenches until it becomes 50 cm above the ground layer. It is then watered carefully and mud plastered. The FYM is ready in about 6 months.

Acid rocks refer to the chemical composition of igneous rocks that has a large percentage of silica content.
Acid rocks have 65 - 70 % of silica and usually contain more than 20% of free quartz.
Typical acid rocks are granite and rhyolite.

Plant's roots are biological organisms having the highest influence on soil aggregate formation.
Plant roots play a vital role in aggregate formation by secreting organic compounds called root exudates. These helps bind soil together near the root zone.
However, Soil aggregates are clumps of soil particles that are held together by moist clay, organic matter (like roots), gums (from bacteria and fungi) and fungal hyphae.

Inceptisols are the soil order that has the highest area in India. It is about 39% and most of the area of Uttar Pradesh is covered by inceptisols soil order.
Followed by Entisols i.e. 24% and alfisols which is 13%.
Inceptisols are soils of relatively new origin and are characterized by having only the weakest appearance of horizons, or layers produced by soil–forming factors.

Vermiculite is a type of clay consisting of two tetrahedral silicate layers coupled with one octahedral magnesium hydroxide-like layer.
Vermiculite is a hydrous phyllosilicate mineral that undergoes significant expansion when heated. Vermiculite clays are weathered micas in which the potassium ions between the molecular sheets are replaced by magnesium and iron ions
. Isomorphic substitution is the process of replacing one structural cation for another of similar size. It only occurs between the cations of similar ionic radii.
In vermiculite, isomorphous substitution mainly occurs at the Tetrahedral sheet.

Sandy soil needs frequent irrigation because of the low water holding capacity of sandy soil.
Water flows down as well as evaporates very quickly from the sandy soil which makes it dry soon. Sandy soil is light, warm and dry and tends to be acidic and low in nutrients as it cannot hold water with it like other clay mixed soils.

Ammonium nitrate will perform very poorly as a source of N fertilizer under a water-logged rice field. Ammonium nitrate is a popular fertilizer with 34% of nitrogen.
The most suitable Nitrogenous fertilizer for submerged Rice fields is ammonium sulphate. It has 21% of N content.

Readily available water in constant matric suction is more in sandy soil.
Matric suction or negative matric potential is the free energy change in a unit volume of water when isothermally transferred from the soil water state to the free water state.
Readily available water is the water that a plant can easily extract from the soil and its value is more when Matric suction is constant in the case of sandy soil as it cannot hold and absorb much water like other soils.