27562 - Soil Quality Indexes

Learning outcomes

At the end of the course, students should have gained the knowledge of the main instruments for chemical and biochemical evaluation of soil quality. Particularly, students should be able to:

- choose the most suitable soil quality indicators to describe soil quality depending on pedo-climate as well as end use;

- evaluate and understand analyses related to soil chemical, biochemical and functional properties;

- evaluate the impact of anthropic and natural events on soil chemical and biochemical properties.

Course contents

The course is divided into several didactic units.

1. Introduction (4 h)

Role and functions of soil in the maintenance of environmental global equilibria. Multi-functionality of soil system. Definition of soil quality. The concepts of indicator and index. Main soil quality indicators and indexes. Fundamental characteristics of soil and soil functionality.

2. Chemical soil quality indicators (18 h)

2.1 The main soil characteristics– the degree of reaction (pH), the texture, the bulk density, the stability of structure, the water availability, the cation exchange capacity, the electrical conductivity.

2.2 Elements in soil– The “pools” of elements in soil, and their mobility. The determination of main nutrients (N, P, S, K, Mg) in soil. Trace element analysis: total and extractable fractions, sequential extractions. Relationships between soil physico-chemical characteristics and trace element bioavailability.

2.3 Not living soil organic matter – utilization of soil organic matter as a soil quality indicator: conceptual aspects. Relationships between soil organic matter and soil functional properties. Chemical fractionation of soil organic matter and humification indices calculation. Relationships between humification indices and soil quality. Physical fractionation of soil organic matter and identification of C and N pools at different stability levels. Effects of different soil management systems on soil physical fractions. Relationships between soil physical fractions and soil quality. Water extractable C and N: definitions, variation factors, extraction methods. Relationships between extractable C and N and soil quality.

3. Biofunctional soil quality indicators (14 h)

3.1. Introduction to the use and application of biofunctional indicators.

3.2 Soil microbial biomass – measurement, meaning and variation factors. Soil microbial biomass respiration: basal respiration, induced respiration, respiration rate, meaning and variation factors. Ecophysiological indexes: Cmic-to-Corg ratio, metabolic quotient (qCO2), and N potential mineralization, meaning and variation factors.

3.2 Catalytic activity of Soils – Catalytic activity of soils: catalytic agents and enzymes: classes, location, heterogeneous kinetics. The soil hydrolytic activity in nitrogen, carbon, phosphorous and sulfur cycles. Soil oxydoreductase activities. The catalytic soil activities as indicators of soil quality.

3.3 The ecophysiological indexes  and the ecological stoichiometry of soil - Concepts, theories and practical applications.

4. Exercises (24 h)

The exercises of the course are organized: in exercises activities in the teaching laboratories of Chemistry, Agricultural Biochemistry and Feed Technology (Lab CBA), and ICT and multimedia (Lab ICT).

4.1 Lab CBA - exercises are focused on: sampling strategies; sample collection, storage and preliminary handling; soil chemical and biochemical parameters analysis: microbial biomass determination, soil basal respiration, ecophysiological indexes, catalytic activities.

4.2 Lab ICT - exercises are employed to analyze and discuss the data obtained in the Lab CBA, and their meaning in terms of soil quality.

Readings/Bibliography

The didactic material will be provided by the teacher and made on-line available, specific reading will be indicated during the course.

Suggested textbooks:

Bloem J. Hopkins D.W., Benedetti A. (ed.s), Microbiological methods for assessing soil quality, CABI Publishing, 2006.

Colombo C., Miano T.M. (ed.s), Metodi di analisi chimica del suolo, 3a versione, SISS, 2015.

Ewing S.A., Singer M.J., Soil Quality (Chap. 26), In: Huang P.M. (ed.), Handbook of Soil Sciences: Resource Management and Environmental Impacts, Second Edition, CRC Press, 2011.

Paul E.A. (ed.), Soil microbiology, Ecology, and Biochemistry. 4th edition, Academic Press, 2014.

Violante P., Chimica e fertilità del suolo, Edagricole, 2013.

Wall D.H. (ed.), Soil ecology and ecosystem services, Oxford University Press, 2012.

Teaching methods

The course is divided into two parts:

1. Frontal lessons: through didactic unit explanations, students should gain knowledge of the main instruments available for the evaluation of soil chemical and biochemical quality. Knowledge acquisition and comprehension skill will be constantly monitored during frontal lessons through a continuous interaction professor-students. Such interaction will be realized by requests from the teacher of discussing different topics of the course related to actual issues close to the subject of the course and will aim at promoting the development of judgment autonomy and improving communication skills

2. Exercises: students should attend laboratory lessons aiming at providing analytical parameters for the definition of soil quality related to its management strategy and use. During lab exercises different series of applications will be proposed; among them students should choose a work program to be followed during the exercises; at the end they will write a concise technical report about the work they carried out. This part of the course will also aim at verifying the ability of applying the knowledge gained about soil system management.

Assessment methods

The learning test of the course of Soil Quality Indicators will be held through the evaluation of the report about laboratory exercises together with the oral presentation of the work. In this occasion, the teacher will also ask some questions aiming at the verification of knowledge acquisition about the theoretical part of the course. The final score will result from the integration of the scores obtained in the two modules composing the integrated course of Soil Chemical and Biochemical Quality. The learning test should be totally passed and students should reach a score of at least 18/30 in both areas of the integrated course. The commission will calculate the final score as the mathematical mean of the scores of each of the two interdisciplinary subjects.

Students who wish to make the exam in English are allowed to do so if they request it at least two days in advance.

Teaching tools

Frontal lessons: overhead projector, PC, projector.

Laboratory exercises will be held in the teaching laboratories of Chemistry, Agricultural Biochemistry and Feed Technology (Lab CBA), and ICT and multimedia (Lab ICT).

Office hours

See the website of Luciano Cavani