Makeup Soil Science Test Paper Solutions 3.0
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Makeup Test Paper Solution 3.0
Q1. A.
Soil pH or soil reaction is an indication of acidity or alkalinity of soil and it measure in PH unit
Q 1 B.
Humus is a complex and rather resistant
mixture of brown or dark brown amorphous
and colloidal organic substance that results
from microbial decomposition and synthesis.
chemical and physical properties of great
significance to soils and plants
Q1. C.
Buffer is a solution in which the mixture of acidic and basic molecules it is registered to change in pH known as buffer.
Q1. D.
The constant movement of air in the soil mass resulting in the renewal of gases is known as soil aeration soil air contains gases like nitrogen Oxygen carbon dioxide and others.
Q1. E.
Soil microorganisms are broadly defined as a group of microscopic life forms that include bacteria, archaea, viruses, and eukaryotes like fungi.
Section B
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Q2. A.
Benefits of Soil organisms :-
Organic matter decomposition.
• Inorganic Transformations
• Nitrogen fixation
• Solubilisation of insoluble phosphorous compounds
• Solubilisation of insoluble Sulphur compounds ( S oxidizing and reducing
organisms)
• Formation and development of soil
• Production of soil enzymes, growth promoting substances and antibiotics
• Detoxification of soil pollutants
• Protect plant roots from invasion by soil parasites and pathogens
Disadvantage of soil Organisms :-
Rodents, snails, slugs, termites, insect larvae and nematodes cause great
damage to plants.
• Mainly fungi, but bacteria and actinomycetes also are responsible for many
soil borne diseases of crop plants.
• Offer lot of competition to higher plants in utilizing the soil available
nutrients, particularly in the presence of carbon sourcesin the soil.
• Under conditions of poor drainage, depletes the available oxygen and
hampers the normal growth of plants.
• Under anaerobic conditions, bacteria transform some of the nutrients to
unavailable form (K & Zn etc.) and some nutrients to be available in toxic
levels (Fe & Mn etc.)
Q2. B.
Soil microorganism needs optimum soil temperature for their proper
functioning in the soil. Soil temperature controls the rate of
microbiological process involved in the mineralization of nitrogen,
nitrogen fixation etc. The optimum soil temperature range for the
microbiological activity is between 25°C to 35°C.
CONTROL OF SOIL TEMPRATURE
➢ By altering soil color.
➢ By vegetative cover.
➢ Mulch.
➢ Moisture present in soil.
➢Irrigation.
Importance of soil temperature
1) It influence seed germination.
2) It influences microbial activity.
3) Indirectly it controls soils formation (weathering of
rocks)
4) It influences plant diseases specially dieback of citrus
Q2. C.
IMPORTANCE OF SOIL ORGANIC MATTER / HUMUS
Influence of Humus / Organic matter on soil physical, biological an d
chemical properties.
• Imparts dark color to soils
• Supplies polysaccharides for binding soil particles for formation of aggregates
(genesis of good soil structure)
• Increases infiltration rate of water and provides better drainage
• Increases water holding capacity
• Reduces plasticity, cohesion, stickiness etc in clay soils
• Reduces bulk density, there by influence porosity favorably
• Through granulation, reduces wind erosion losses
• Provides mulching (raw organic matter) and lowers soil temperature during summer
Q2. D.
Soil genesis or pedogenesis is the study of the origin and formation of soil.
Soil genesis or pedogenesis is the study of the origin and formation of soil. Pedologists conceptualize soil as a natural, three-dimensional body on the Earth's surface
Q2. E.
Humus is a complex and rather resistant
mixture of brown or dark brown amorphous
and colloidal organic substance that results
from microbial decomposition and synthesis.
chemical and physical properties of great
significance to soils and plants.
Properties of Humus
1. The tiny colloidal particles are composed of
C, H, and O2.
2. Humus has a very favorable effect on
aggregate formation and stability.
3. Impart black colour to soils.
Q2. F.
Soil aeration:
Constant exchange of gases from soil to atmosphere or
vice versa results in renewal of component of gases
of soil air is called as soil aeration.
Importance of soil aeration
• It influences plant growth .
• It is required for microbial activity .
• Under anaerobic condition toxic substances/gases, for
example, methane, hydrogen sulphide are produced
• Due to improper aeration it causes fruit diseases.
• Nutrient absorption is also affected due to low quantity of
oxygen present in the soil.
Section C
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Q3. A.
Factors Affecting Soil Water
1) Texture: Finer the texture, more is the pore space and also surface area,
greater is the retention of water.
2) Structure: Well-aggregated porous structure favors better porosity, which in
turn enhance water retention.
3) Organic matter: Higher the organic matter more is the water retention in
the soil.
4) Density of soil: Higher the density of soil, lower is the moisture content.
5) Temperature: Cooler the temperature, higher is the moisture retention.
6) Salt content: More the salt content in the soil less is the water available to
the plant.
7) Depth of soil: More the depth of soil more is the water available to the plant.
8) Type of clay: The 2:1 type of day increases the water retention in the soil.
Movement of soil water
1) Saturated flow
2) Unsaturated flow
3) Vapour flow
1. Saturated Flow :- water logged soil or submerged
soil. Water movement takes place under such
condition is called as saturated flow.
2. Unsaturated Flow :-
unsaturated soil (moist
soil), water movement taking place under such
condition is called as unsaturated flow.
3. Evapour movement
Conservation of soil water into vapour form
which may take place within the soil or from
soil surface to atmosphere.
Q4. A.
SOILPOLLUTION
• It is defined as the build-up in soils of persistent
toxic compounds, chemicals, salts, radioactive
materials, or disease causing agents, which have
adverse effects on plant growth and animal health.
Causes of SoilPollution
• Seepage from a landfill
• Discharge of industrial waste into the soil
• Percolation of contaminated water into the soil
• Rupture of underground storage tanks
• Excess application of pesticides, herbicides or
fertilizer
• Solid waste seepage
• Deforestation and Soil erosion
Agricultural SoilPollution
• Plants on which we depend for food are under attack
from insects, fungi, bacteria, viruses, rodents and other
animals, and must compete with weeds for nutrients.
Agriculturaleffects:
• Reduced soil fertility
• Reduced nitrogen fixation
• Increased erodibility
• Larger loss of soil and nutrients
• Deposition of silt in tanks and reservoirs
• Reduced crop yield
• Imbalance in soil fauna and flora.
GroveStudies Production:
Q4. B.
Dokuchaiev, (Father of Soil Science) viewed the soil as a natural body composed of mineral and
organic constituents, having a definite genesis and distinct nature of its own.
• Soil is defined as a dynamic natural body on the surface of the earth in which plants grow, composed of
mineral and organic materials and living forms. -Buckman and Bardy
Soil can be classified into three primary types based on its texture – sand, silt and clay. However, the percentage of these can vary, resulting in more compound types of soil such as loamy sand, sandy clay, silty clay, etc.
Q.5 A.
Classification of soil water
Soil water has been classified from a physical and biological point of view as
Physical classification of soil water and biological classification of soil water.
Physical classification
a) Gravitational water
b) Capillary water
c) Hygroscopic water
Biological Classification
a) Available water
b) Unavailable water
c) Super available or superfluous water
PHYSICAL CLASSIFICATION OF SOIL WATER
1. Gravitational water: Gravitational water occupies the larger soil pores
(macro pores) and moves down readily under the force of gravity.
2.. Capillary water: Capillary water is held in the capillary pores (micro
pores).
3. Hygroscopic water: The water that held tightly on the surface of soil
colloidal particle is known as hygroscopic water.
Importance of soil water
• Water itself act as a principal constituent for plant growth.
• It acts as a solvent.
• It acts a carrier for carrying essential plant nutrients.
• It regulates soil temperature.
• It also control soil forming processes.
• It is essential for microbial activity.
• It determines crop productivity
Q5. B.
SOIL PROFILE
The soil profile may be defined as a vertical section of soil from the surface down to the hard rock from
which the soil is formed (or the vertical section of the soil showing the various layers from the surface to the
unaffected parent material (bed rock) is known as a soil profile). A soil profile is a historic record of all the soil
forming processes and factors governing the soil formation.
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