96971 - Chemistry and Biochemistry of the Soil-Plant System

Learning outcomes

After teaching the student possesses the basic knowledge on the genesis of soils, their composition and physico-chemical and biological properties. The information provided makes it easy to understand the mechanisms that regulate the activity of soil surfaces and functions of agro-ecosystems.

Course contents

CHEMISTRY AND BIOCHEMISTRY OF THE SOIL-PLANT SYSTEM

(Bachelor's Degree in Science and Technology for Green and Landscape)

MODULE 1. SOIL CHEMISTRY (30 hours – Prof. Claudio Marzadori)

1.1 Soil constituents (8 hours)

Mineral constituents: minerals, crystals, ionic radii and coordination numbers, silicates, phyllosilicate structure, allophane, oxides and hydroxides, carbonates.

Organic constituents: classification and transformation processes. Non-humic substances: carbohydrates, nitrogenous, phosphorus, and sulfur compounds, lipids. Humic substances: extraction, fractionation, classification, composition and chemical-physical properties.

1.2 Soil physical and chemical properties (12 hours)

Surface properties: specific surface of soil particles, origin of charges.

Adsorption and cation exchange: models, thickness and potential of the double layer, exchange bases, exchange characteristics, C.S.C., affinity, lyotropic series, exchange equations, dilution effects.

Adsorption and anion exchange: anions in soil, specific adsorption. The adsorption of phosphates, isotherms and equations, dissolution-precipitation mechanisms.

Soil reaction: definition and measurement of soil pH, active and exchangeable acidity, soil classification based on pH, pH and nutrients, pH and soil biological activities, main buffer systems and pH’s soil regulation mechanisms.

The rhizosphere: rhizodepositions and the formation of the rhizosphere. Chemical properties of the rhizosphere. Rhizosphere and availability of nutrients

1.3 Anomalous soils (10 hours)

Acidic soils: formation, chemical/physical characteristics, correction.

Saline soils: formation, chemical/physical characteristics, correction.

Sodic soils: formation, chemical/physical characteristics, correction.

MODULE 2. SOIL FERTILITY (30 hours – Dott.ssa Martina Mazzon)

2.1 The carbon cycle (6 hours)

Long-term and short-term cycle: geological C cycle, biological C cycle, net primary production, soil organic matter.

The soil microbial component and enzymatic activities: the organic component and the living biomass, enzymatic catalysis, classes of enzymes in the soil. Enzymes involved in the carbon cycle (hydrolytic and oxidative).

2.2 Elements of plant nutrition and their mobility in the soil (12 hours)

Nutrients in the soil: availability and dynamics in the soil-plant system (interception, flow and loss).

The nitrogen cycle: fixation (biological and chemical), mineralization and immobilization, volatilization (ammoniacal N), nitrification and denitrification, leaching, nitrification inhibitors. The enzymes involved in the N cycle

The phosphorus cycle: organic and inorganic forms present in the soil, role in plants and absorption, phosphorus and pH, sufficiency thresholds in the soil. The enzymes involved in the cycle of P.

Mineral and organic fertilization.

2.3 Micronutrients in the soil (6 hours)

Iron: biogeochemical cycle and absorption

Manganese: biogeochemical cycle and absorption

Zinc: biogeochemical cycle and absorption

Copper: biogeochemical cycle and absorption

2.4 Soil analysis and interpretation (6 hours)

Analytical procedures for the determination of: pH, total limestone, available P, biomass and microbial activity.

Soil analyses’ interpretation.

Simplified approach to statistical data analysis.

Readings/Bibliography

he use of teacher didactic material, provided in the class lectures and online available, besides lessons notes, will be of fundamental importance.

The following book is recommended

AA.VV. Paolo Sequi Coord., Patron Ed. Bologna

Teaching methods

The course is subdivided into two parts:

1) Class lectures: Students should gain the knowledge on the chemical, biochemical and microbiological processes at the basis of soil functioning, through class lectures. Knowledge acquisition and comprehension skills will be constantly monitored, during class lectures, through a continue interaction between the students and the teacher. Such interaction consists in requests by the teacher of discussing some topics of the course, for their impact on current issues linked to the subject of the course, and will aim at developing judgement autonomy and improving communication skills

2) Exercises: Students should attend laboratory experiments, aiming at providing analytical results for the investigation of chemical and biological processes related to a certain soil. Such part of the course will also aim at verifying the ability of applying the theoretical knowledge about the managing of soils.

Assessment methods

The learning test for the course is made through a final oral examination, carried out together with the exam of the integrated course. The oral exam deals with the topics developed in the lessons Starting from this scheme, appropriate investigations related to the discussed topics will take place. The exam must be completely passed and the candidate must reach at least a score of 18/30 in each of the learning subjects of the integrated course. The academic board will express the final evaluation by calculating a weighted mean of the scores of each learning subject. You can, on request, sustain the final exam in English.

Teaching tools

Overhead projector, personal computer and projector will be used for class lectures.

Laboratory exercises will take place in the didactic laboratories of Agricultural Chemistry and Biochemistry.

Office hours

See the website of Claudio Marzadori

See the website of Martina Mazzon