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SSAC 506 SOIL BIOLOGY AND BIOCHEMISTRY                                                                               (4L+1P) II

Objective
To teach the students the basics of Soil Biology and Biochemistry including nutrient transformation and cycling at the soil-root interface, bioremediation of the contaminated and polluted soils and also the microbial interactions in the soil

Theory

UNIT I
Soil as biological habitat; soil organisms (flora and fauna) – their ecology and diversity; unculturable soil biota.

UNIT II
Rhizosphere biology: Relationships between plant roots and rhizosphere flora.

UNIT III
Energy relationships in organic matter decomposition, energy flow in the plant-microorganisms system; soil enzymes involved in organic matter break down and plant nutrient transformations; microbiology and biochemistry of decomposition of carbonaceous materials: cellulose, hemi- cellulose, lignin and minor plant constituents.

UNIT IV
Microbiology and biochemistry of decomposition of proteinaceous materials; N-cycle, C:N ratio and its importance; theories of humus formation and microbial processes involved; role of humus in soil.

UNIT V
Symbiotic N fixation: The symbionts, biochemical mechanisms of N fixation, factors affecting, importance in sustainable agriculture; microbiology and biochemistry of non-symbiotic N fixation; nitrification, de-nitrification - organisms involved, mechanisms and importance in agriculture; biology of transformation of phosphate solubilization; sulphur, zinc, iron and manganese transformations in soil.

UNIT VI
Biological indicators of soil quality; bioremediation of contaminated soils; microbial transformations of heavy metals in soil; role of soil organisms in pedogenesis - important mechanisms and controlling factors; soil genomics and bioprospecting; soil sickness due to biological agents; xenobiotics; antibiotic production in soil.

List of Practicals
Isolation and enumeration of soil microorganisms by serial dilution plate technique; estimation of microbial biomass carbon in soil; study of organic matter decomposition in soil as affected by varying C:N ratio of crop residues (CO2 evolution method); determination of dehydrogenase activity in soil; study of acid and alkaline phosphomonoesterases in rhizosphere soil samples; determination of arylsulphatase activity in soils; enumeration of nitrifiers by most probable number method; study of potential nitrogen mineralization in soil; determination of free-living N2 fixation in soil; determination of soil microbial population; soil microbial biomass; soil enzymes.

Selected Readings