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SSAC 503/ AP 503 FUNDAMENTALS OF SOIL PHYSICS                                                                               (3L+1P) I

Objective
To impart knowledge about physics and physical properties of soil and their role in its management

Theory

UNIT I
Basic principles of physics applied to soils viz. viscosity, surface tension, capillarity, stress-strain relations, gaseous diffusion, heat transport, thermodynamic principles; properties of water in relation to porous media.

UNIT II
Physical characterization of soil; soil as a polyphase system; mass-volume relationships.

UNIT III
Particle size distribution; soil texture; mechanical analysis; specific surface; clay - a colloidal surface; hydration of clays.

UNIT IV
Soil structure and aggregation: genesis, classification and evaluation; soil structural stability and indices; soil tilth; soil conditioners.

UNIT V
Geometry of pore space and pore size distribution; inter- and intra-aggregate pores; soil consistency and its limits; consistency and deformation of cohesive soils; compaction and crusting in soils; soil strength and its measurement.

UNIT VI
Geometry of water phase; energy state of soil water; water content and potential and their measurement; different components of soil water potential; soil water characteristics, hysteresis and available water.

UNIT VII
Flow of water in soil; Darcy’s law, hydraulic conductivity and water diffusivity; saturated and unsaturated flow and equations; methods for saturated and unsaturated hydraulic conductivity measurement - both in situ and in laboratory; capillary movement of water, contact angle.

UNIT VII
Entry of water into soil and its redistribution; permeability; evaporation from bare soil; modification of soil surface affecting infiltration and evaporation; field water balance.

UNIT IX
Gaseous phase in soil, content and composition; renewal of soil air and gaseous diffusion; measurement of soil aeration; factors affecting soil aeration.

UNIT X
Energy balance in bare soil; soil heat flux, heat capacity, specific heat and thermal diffusivity; soil temperature and its measurement, factors affecting; thermal regime in soil profile.

Practicals
Particle size analysis of soil; determination of bulk density, particle density and mass-volume relationships of soil; soil aggregate analysis; measurement of soil moisture content and soil moisture potential; determination of soil-moisture characteristic curve, saturated and unsaturated hydraulic conductivity, and infiltration characteristics of soil; determination of Atterberg constants; measurement of soil strength and soil temperature.

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