65857 - Agricultural chemistry and soil fertility

Learning outcomes

Upon successful completion of the course, students will possess the fundamental knowledge and practical skills required to understand the major molecular and functional processes occurring in plants, both at the cellular and whole-organism levels, with particular emphasis on the interactions within the soil–plant–atmosphere continuum. Students will also acquire the scientific tools needed to evaluate plant productivity and ecosystem functioning in relation to carbon and nitrogen dynamics, resource-use efficiency, and environmental sustainability. Furthermore, they will be able to interpret the biochemical and physiological mechanisms underlying plant responses to environmental constraints and their implications for the sustainable management of agricultural and forest ecosystems.

Course contents

The course Agricultural Biochemistry and Soil Fertility provides the knowledge required to understand the processes governing the acquisition, transformation and utilization of resources by plants, as well as the interactions occurring within the soil–plant–atmosphere system.

The course integrates the biochemical aspects of plant metabolism with those related to nutrient availability and uptake in soils, providing a comprehensive understanding of the processes that determine plant growth, biomass production, resource-use efficiency and the sustainability of agricultural and forest ecosystems.

The Agricultural Biochemistry module focuses on the main metabolic processes involved in carbon and nitrogen acquisition and utilization by plants, with particular emphasis on the relationships among photosynthesis, respiration, biomass production, environmental stress responses and resource-use efficiency.

The Soil Fertility module addresses the processes regulating nutrient availability and mobility in soils, root nutrient uptake, rhizosphere processes, major biogeochemical cycles, plant mineral nutrition and the management of soil fertility through fertilizers, amendments and soil conditioners.

The integration of the two modules enables students to interpret the functioning of the soil–plant–atmosphere system by linking cellular biochemical processes with plant nutrition, biomass production and the sustainable management of agricultural and forest ecosystems.

Prerequisites

Basic knowledge of Biology, General Chemistry and Organic Chemistry acquired during first-year courses is recommended.

Programme

MODULE 1 - AGRICULTURAL BIOCHEMISTRY

1. Plants as biochemical systems.

• Organization of the plant cell.

• Water and biological systems.

• Major biomolecules: carbohydrates, lipids, proteins and nucleic acids.

• Plant metabolism and matter and energy flows in agricultural and forest ecosystems.

2. Enzyme, bioenergetics and respiration.

• Enzymes and biological catalysis.

• ATP and energy transfer.

• Glycolysis.

• Tricarboxylic acid cycle.

• Respiratory electron transport chain and oxidative phosphorylation.

• Biological significance of respiration and metabolic costs of growth.

3. Photosynthesis and carbon assimilation.

• Light reactions of photosynthesis.

• Calvin-Benson cycle.

• Photorespiration.

• C3, C4 and CAM photosynthetic pathways.

• Photosynthetic efficiency and carbon acquisition.

4. Biomass production and Carbon Use Efficiency (CUE)

• Sucrose synthesis and transport.

• Starch accumulation.

• Source-sink relationships.

• Biomass allocation among plant organs.

• Carbon Use Efficiency (CUE): definition, biochemical determinants and ecological significance.

5. Nitrogen metabolism and Nitrogen Use Efficiency (NUE)

• Uptake and transport of nitrate and ammonium.

• Nitrate reduction.

• GS-GOGAT cycle.

• Amino acid and protein biosynthesis.

• Integration of carbon and nitrogen metabolism.

• Nitrogen Use Efficiency (NUE): definition, components and applications.

6. Secondary metabolism and environmental adaptation

• Shikimate pathway.

• Phenolic compounds, flavonoids and terpenoids.

• Lignin biosynthesis.

• Secondary metabolites, plant defence and stress adaptation.

7. Environmental stresses and metabolic resilience

• Drought, heat and salinity stress.

• Oxidative stress and reactive oxygen species.

• Antioxidant systems.

• Effects of environmental stress on carbon and nitrogen metabolism.

• Impacts of stress on CUE and NUE.

8. Plant metabolism and sustainability

• Biomass production and carbon sequestration.

• Resource-use efficiency in agricultural and forest ecosystems.

• The role of plant metabolism in climate change adaptation and mitigation.

• CUE and NUE as indicators of the biological sustainability of plant systems.

 

MODULE 2 - SOIL FERTILITY

1. Plant Nutrients in Soil and Short-Distance Transport

• Essential plant nutrients.

• Apoplastic transport.

• Symplastic transport.

• Types of membrane transport systems (carriers, pumps and channels).

• Primary and secondary active transport.

2. Nutrient Availability and Mobility in Soils

• Nutrients in soil and their reserve forms.

• Factors affecting nutrient availability: soil properties, management practices, microbial activity and root activity.

• Root exudation and rhizosphere formation.

3. Nitrogen in the Soil–Plant–Atmosphere System

• Forms of nitrogen in soils.

• The ammonium sub-cycle.

• Soil–plant nitrogen redox sub-cycle.

• Soil–atmosphere nitrogen redox sub-cycle.

4. Phosphorus

• Forms of phosphorus in soils.

• Inorganic phosphorus and factors affecting its bioavailability.

• Organic phosphorus and factors affecting its bioavailability.

5. Iron

• Iron in soils and its availability.

• Strategy I for iron acquisition.

• Strategy II for iron acquisition.

6. Fertilizers, Soil Amendments and Corrective Materials

• Classification, properties and regulatory aspects of the main nitrogen, phosphorus and potassium fertilizers.

• Classification, properties and regulatory aspects of the main soil amendments and corrective materials.

• Soil amendments and soil quality.

Readings/Bibliography

Required References

AGRICULTURAL BIOCHEMISTRY:

• Chesworth J.M., Stuchbury T., Scaife J.R., An introduction to Agricultural Biochemistry, Chapman & Hall.

• Taiz L., Zeiger E., Møller I.M., Murphy A., Plant Physiology and Development.

SOIL FERTILITY:

• Benton Jones J., Plant Nutrition and Soil Fertility Manual, CRC Press.

Recommended Reading

AGRICULTURAL BIOCHEMISTRY:

• Buchanan B.B., Gruissem W., Jones R.L., Biochemistry and Molecular Biology of Plants, Wiley-Blackwell.

• Lambers H., Oliveira R.S., Plant Physiological Ecology, Springer

SOIL FERTILITY:

• Marschner P., Marschner's Mineral Nutrition of Higher Plants.
• Strawn D.G., Bohn H., O'Connor G.A., Soil chemistry, Wiley.

Teaching Materials

Lecture slides, selected scientific papers and additional teaching materials will be made available through the University e-learning platform.

Students are expected to master the topics discussed during lectures and the teaching materials provided by the instructor.

Teaching methods

The course is delivered through face-to-face lectures supported by multimedia presentations, conceptual diagrams, explanatory figures and selected bibliographic resources.

Teaching activities are designed to promote the understanding of the biochemical and nutritional processes governing the functioning of the soil–plant–atmosphere system, with particular emphasis on the relationships among plant metabolism, nutrient availability, biomass production and the sustainability of agricultural and forest ecosystems.

Within the Agricultural Biochemistry module, particular attention is devoted to the interpretation of carbon and nitrogen fluxes in plants, the relationships among photosynthesis, respiration and growth, and the role of resource-use efficiency in productivity and adaptation to environmental stresses.

Within the Soil Fertility module, the course addresses the processes regulating nutrient availability and uptake, rhizosphere functioning, major biogeochemical cycles and soil fertility management practices.

Throughout the course, examples and case studies are used to illustrate:

• biomass production in agricultural and forest ecosystems;

• carbon and nitrogen use efficiency;

• interactions between plant roots and soil;

• plant mineral nutrition;

• the effects of environmental stresses on plant productivity;

• sustainable soil fertility management.

Guided analysis of conceptual schemes, scientific figures, experimental data and case studies is used to foster the ability to connect biochemical, nutritional and ecological processes and to apply the acquired knowledge to issues related to crop production, forest ecosystem functioning and sustainable natural resource management.

Teaching materials may include conceptual maps, diagrams and case studies developed during the course to facilitate the integration of biochemical, nutritional and ecological perspectives.

The course does not include laboratory activities or practical sessions involving specific safety risks.

Assessment methods

Learning outcomes are assessed through a comprehensive oral examination within the integrated course of Agricultural Chemistry.

The examination covers the entire programme, including the topics developed in the modules of Soil Chemistry, Agricultural Biochemistry and Soil Fertility.

The assessment is designed to evaluate:

• knowledge of the main chemical, biochemical and nutritional processes governing the functioning of the soil–plant–atmosphere system;

• understanding of the relationships among nutrient availability, plant metabolism, biomass production and soil fertility;

• the ability to integrate concepts and processes discussed across the different modules of the integrated course;

• the appropriate use of scientific terminology;

• the ability to critically discuss issues related to plant productivity, soil fertility and the sustainability of agricultural and forest ecosystems.

The oral examination consists of the discussion of topics included in the course programme and may involve the interpretation of conceptual schemes, scientific figures, experimental data and simple case studies.

The examination is conducted by one of the instructors responsible for the integrated course. The final grade is expressed on a 30-point scale.

Assessment criteria

18–19: basic knowledge of fundamental concepts; limited ability to connect different processes and acceptable use of scientific terminology.

20–24: adequate knowledge of the topics covered in the course; ability to correctly describe the main processes and establish simple links among soil properties, plant nutrition and metabolism.

25–27: good knowledge of the course contents; ability to integrate different aspects of the discipline and correctly interpret the relationships among soil, plants and the environment.

28–30: thorough and critical understanding of the course topics; ability to effectively connect the chemical, biochemical and nutritional processes governing agricultural and forest ecosystems; full command of the appropriate scientific terminology.

30 cum laude: outstanding preparation, autonomous critical thinking and synthesis skills, rigorous use of scientific terminology, and the ability to discuss in an integrated and comprehensive manner the relationships among soil fertility, plant metabolism, productivity and sustainability.

As the assessment is based on an in-person oral examination, the use of Generative Artificial Intelligence tools is not applicable during the examination itself. Any AI-assisted study materials remain the responsibility of the student and do not replace the independent acquisition of the knowledge required to successfully complete the examination.

Students with specific learning disabilities (SLD) or temporary/permanent disabilities are encouraged to contact the University's dedicated support services in advance to discuss any appropriate accommodations, in accordance with the learning objectives of the course.

Teaching tools

Particular attention is devoted to the development of conceptual frameworks that integrate the processes governing the functioning of the soil–plant–atmosphere system, highlighting the relationships among nutrient availability, plant metabolism, biomass production, responses to environmental stresses, and the sustainability of agricultural and forest ecosystems.

To support learning, selected teaching materials will be made available through the University e-learning platform. These may include:

• lecture presentations;

• summary schemes of the main metabolic and nutritional processes discussed during the course;

• figures and diagrams illustrating the metabolic pathways covered in the programme;

• materials related to the case studies discussed during the lectures;

• supplementary bibliographic resources;

• scientific and outreach articles for further study;

• links to databases and online resources relevant to the discipline.

Teaching materials will be organized to support both attending students and independent study by non-attending students.

The informed use of Generative Artificial Intelligence tools may provide support for activities such as further exploration of course topics, summarization and self-assessment. Students are nevertheless encouraged to critically evaluate the scientific reliability of AI-generated information and to use such tools as a complement to, rather than a substitute for, independent learning and consultation of the recommended scientific sources.

Office hours

See the website of Luciano Cavani

See the website of Claudio Marzadori