Physical Properties of Soil MCQ Quiz in मल्याळम - Objective Question with Answer for Physical Properties of Soil - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct answer is Decreases.

• With the addition of organic matter, the Bulk density of soil is Decreases.
• Bulk density of soil: It is defined as the dry weight of soil per unit volume of soil.
• It considers both the solid and pore space of the soil.

The correct answer is Hygroscopic coefficient.

• The hygroscopic coefficient and the maximum capillary capacity are the two equilibrium points when the soil contains the maximum amount of hygroscopic and capillary waters, respectively.

 

• The hygroscopic coefficient is the maximum amount of hygroscopic water absorbed by 100 g of dry soil under standard conditions of humidity (50% relative humidity) and temperature (15°C).
• This tension is equal to a force of 31 atmospheres.
• Water at this tension is not available to plant but may be available to certain bacteria.

 

​Additional Information

1. Capillary water :

• Water is held in the capillary pores (micro pores).
• Capillary water is retained on the soil particles by surface forces.
• It is held so strongly that gravity cannot remove it from the soil particles.
• Capillary water is known as available water.
• The capillary water is held between 1/3 and 31 atmosphere pressure.
  
   

2. Field capacity:

• It is the capacity of the soil to retain water against the downward pull of the force of gravity.
• At this stage, only micro pores or capillary pores are filled with water and plants absorb the water for their use.
• Water is held with a force of 1/3 atmosphere.

 

3. At permanent wilting point water is held at -15 bars.

sand fraction mainly consists of quartz. In addition to this, other primary minerals like feldspars, micas, pyroxene, olivine are also found. In small amounts of secondary minerals eg. oxides of aluminium (gibbsite) and iron (hematite) are also found.

Process of interbreeding between individuals of different species (interspecific hybridization) or genetically divergent individuals from the same species (intraspecific hybridization) to obtain new variety or a hybrid is known as Hybridization. Offspring produced by hybridization can be fertile, partially fertile, or sterile.

The correct answer is Low pH, less ESP and more EC.

• Found in white crust of salt hence called white alkali/solon chalk.
• Soluble salt i.e. Cl and SO4 ions of sodium and calcium in root zones.
• Found in arid and semi-arid zones.

Soil	pH	ESP	EC
Saline	< 8.5	< 15	> 4
Alkali / Sodic	8.5-10	> 15	< 4
Saline-alkali	> 8.5	> 15	> 4

The correct answer is ​>2.0 mm.

• The particle size of the gravel is  ​>2.0 mm.

 

Classification	Soil particle size (dia in mm)
Gravel	>2.0
Coarse Sand	0.2-2.0
Fine sand	0.02-0.2
Silt	0.002-0.02
Clay	<0.002

The correct answer is 0.02 - 0.2.

Soil separates	Diameter (mm)
Clay	< 0.002
Silt	0.002 - 0.02
Fine sand	0.02 - 0.2
Coarse sand	0.2 - 2.0

C : N ratio of soil varies from 5 : 1 to 15 : 1 in most arable soils. Average carbon/nitrogen ratio can be taken as 10 : 1.

C : N ratio in plant ranges from 20 : 1 to 30 : 1, highest in legumes. C : N ratio in farm yard manure can be as high as 100 : 1.

Soil Water Potential and Moisture retention is an intrinsic property of the soil, which depends on particle packing, texture and type of soil particles. Loosely packed Soil having bigger grains (like Sand) have lower Soil Water Potential and moisture retention. Clay soils can hold much more water as compared to loamy and sands.

In term of Soil Water Potential and moisture retention, soils can be arranged as following:

Clay > Loamy > Sandy

The correct answer is Beyond 25 cm.

Key Points

• Hypermetropia is a defect of vision that causes the impossibility for rays of light to be focused on the retina but behind it.
• It is caused by light not being correctly focused, with light traveling behind the retina.
• People with hypermetropia can focus only on far objects, relying on accommodation, that is the lens contraction performed by the ciliary muscle.
• It is corrected with converging or positive lenses (convex lenses).
• The near-point of a hypermetropic eye is more than 25 cm away. Hence, a far-sighted vision defective person place a reading material beyond 25 cm from the eyes for comfortable reading