Soil Chemistry and Biology

Objectives and competences

As compared to the environmental compartments air and water, soil is an extremely complicated system. This is due to a huge variety in soil composition and to the
interaction among soil components, which in turn module and are modulated by chemical, physical and biological system condition. Soil can be a source, a sink, or an
interacting medium for many nutrients, as well as contaminants that impact humans, plants, wildlife, and other organisms.
An understanding of soil properties and processes is therefore critical to the evaluation and the criteria to be adopted for the soil management.


Knowledge of biology, physics, chemistry and biochemistry.


The soil environment
The soil environment is constituted by three different physical phases that interact among them. The main properties of these phases and the biochemistry of soil will be introduced.

The solid phase

Composition of the solid phase
Minerals, organic components, and micro organisms are integral parts of the pedosphere and associated environments. The following topics will discussed in depth: The inorganic components: silicates, metal oxides and hydroxides; soil organic matter: organic materials and chemical components of soil organic matter.
Physical properties of solid phase
Grain size distribution of solid particles and their structural organization.
Particle surfaces and related chemical properties -
The cation exchange capacity and the anionic adsorption;
Chemical reaction of soil; Anomalous soils:
acidification and Al-rich soils; alcalinization, sodic
and salty soils.

Water and air in the soil
Relationship between fluids and soil structure and porosity;
Water movement and retention; Gas exchange between soil and the atmosphere.

Soil biochemistry

  • Soil as biological system
    Soil organisms are responsible for many important biochemical reactions, contribute to the soil fertility and carry out relevant environmental functions. The following properties of soil organisms will be discussed:
    a.) Soil organisms;
    b.) Living organisms on soil properties;
    c.) Soil enzymes;
    d.) Biochemical concept of microbial population)

-main biogeochemical cycles
Soil physical, chemical and biochemical properties influences the availability of nutrients. It is important to know the biogeochemical cycle of nutrients in order to optimize supplies, reduce nutrient losses and preserve the ecosystem equilibrium. The C cycle will be considered first, because it influences all other cycles. Afterwards, the others cycles will be discussed: Carbon: soil organic matter humification and mineralization; agronomical functions of soil organic matter: Nitrogen; Phosphorus;

Fertilizers and fertilization

• Evaluation of soil Fertility
• Traditional and innovative fertilizers
• Biomasses and soil amendment
• Fertilization schemes
• irrigation water quality

Soil and environment
• Role of the soil in the environmental equilibrium
• Anomalous composition and natural degradation processes
• Use and recycling of biomasses
• Soil and pollution (inorganic pollutants, organic pollutants)

Operative exercises will be provided in lab. at step of the each topic.

Intended learning outcomes

Knowledge of basic properties of soil components (silicates, carbonates, metal oxides, sulphides, organic matter)
knowledge of basic chemical, biochemical and biological soil processes (cation and anion retention, pH, microbial biomass, enzymes activity, ...)
knowledge of chemistry and biochemistry of plant macro- and micro- nutrients
Soil classification
Knowledge of main soil contaminants (organic and inorganic)


• Coleman, D.C.; Crossley, J. 1995. Fundamentals of soil ecology. San Diego etc.: Academic press, 205 str.
• White, R.E. 1997. Principles and practice of soil science: the soil as a natural resource / - 3rd ed. - Oxford: Blackwell science, 348 str. E-version

Slides, Moodle and Miteam classroms


Laboratory practice examination, lecture written examination (30/70)

Lecturer's references

Associate professor for the field of Biotechnology at University of Nova Gorica.

References .