93958 - Plant Nutrient Management and Recycling in Agricolture

Learning outcomes

At course completion, the student possesses knowledge on: key procedures in the soil nutrient cycle and their relationship with the soil-climate-plant system; rational fertilization management techniques with the awareness of: new generation formulas, their instructions according to precise and sustainable agriculture; recycling techniques in biomass soils of agro-industrial origin, and the recovery of the nutrients contained in them. In particular, the student possesses the skills to: organize a fertilization plan at a field and company level; measure soil fertility; recognize the main types of fertilizers; assess agronomic and economic values of biomasses of agro-industrial origin and plan their use in agricultural soils; intervene in biomass transformation procedures with the purpose of improving agronomic performance.

Course contents

Course contents

A) Pre-skills

Students attending this course should possess a background on soil chemistry and plant biochemistry. Students should gain familiarity with the use of electronic spreadsheets for data handling before the course and GIS software (QGIS).

B) Didactic units

The course is divided in 7 didactic units

UNIT 1. Introduction to plant nutrient management and recycling in agriculture (4 hours)

1.1. The concept of sustainable farming. Environmental impacts of agriculture and related activities and their control in the carbon-farming framework.

1.2. Introduction to the carbon and nitrogen cycle.

1.3. The phosphorus (P) cycle. Phosphorus as critical raw material.

Knowledge gained in Didactic Unit 1: Agriculture and environment interaction. Connections between carbon and the nitrogen cycles. Relevance of phosphorous as non-renewable resource.

UNIT 2. Main soil characteristics (4 hours)

2.1. Main mineral and organic soil components. Main soil water reactions. Main redox reactions in soils. Main surfaces’ properties of soil colloids.

2.2. Organic matter and microbial biomass.

2.3. Nitrogen and carbon mineralization process in soil (C/N ratio; stability; temperature and moisture effect), and its effect on plant nutrient availability.

2.4. Phosphorous forms in soil (organic P; inorganic P; total P; plant-available P), phosphorous precipitation and release.

Knowledge gained in Didactic Unit 2: Main soil components (mineral and organic); Main soil water reactions; Main redox reactions in soils.

UNIT 3. Plant nutrition and soil fertility (4 hours)

3.1. Essential elements. Non-mineral and mineral nutrients. Plant nutrient uptake e reallocation. Soil fertility. Nutrient mobility in soils.

Knowledge gained in Didactic Unit 3: essential elements for plant nutrition. Function and mobility of nutrients within plants. The forms of nutrient taken up by plants. Typical nutrient plant concentrations. Nutrient needs change during the growing season.

UNIT 4. Mineral and organic fertilizers, nutrient utilization efficiency (4 hours)

4.1 Fertilizers classification (mineral, organic and organic-mineral fertilizers; soil conditioners, anaerobic digestates; liming materials, bio-stimulants, smart fertilizers).

4.2. Chemical fertilizers from organic waste recycling (Struvite; NH₄SO₄).

4.3. Fertilizers nutrient efficiency (apparent nutrient utilization, agronomical efficiency);

Knowledge gained in Didactic Unit 4: Chemical and innovative fertilizers knowledge. Assessment of crops nutrient efficiency from chemical and organic fertilizers (mainly N; P; K). Soil and fertilizer N contribution to plant nutrition.

UNIT 5. Organic waste recycling for crop fertilization and soil fertility (12 hours).

5.1. Recycling of animal manure, anaerobic digestate, compost, sewage sludge, biochar.

5.2. Nutrient content in recycled organic waste (N; P). Potential nutrient availability from recycled organic waste (nitrogen speciation; phosphorus speciation).

5.3. Carbon content and quality from recycled organic waste.

5.4. The carbon management index (CMI) as a tool to compare different fertilization strategies in the light of winning carbon soil management.

Knowledge gained in Didactic Unit 5: Chemical and physical characteristics of the most common recycled organic waste available for agricultural uses. Rational soil carbon management.

UNIT 6. Sustainable fertilization strategies (12 hours)

6.1. Sustainable fertilization strategies (testing soil nutrient content and plant availability).

6.2. Assessing crops nutrient requests; planning fertilization strategies on sustainable basis (soil test and crop nutrient requests).

6.3. Monitoring crop performances (physical monitoring in fields, remote-sensing via vegetation index assessment).

6.4. Carbon-farming (maximize the crop nutrient request preserving/increasing the soil organic matter content).

Knowledge gained in Didactic Unit 6: improvement of a rational fertilization plan based on soil test and satellite derived vegetation index (NDVI), in a GIS environment.

UNIT 7. Seminars and exercises (20 hours)

Seminars. A cycle of seminars with invited speakers focused on key topics of the course will be organized.

Exercises. Individual and/or group exercises will be held in the classroom. During the exercises, practical tasks on key topics of the course will be assigned to be solved individually or in group.

Readings/Bibliography

The didactic material will be provided by the teacher and made available on-line (https://virtuale.unibo.it/my/), specific readings will be indicated during the course.

Suggested textbooks:

Blume et al. (2016), SOIL SCIENCE, Springer (chapters: 1-3, 5, 10).

Strawn et al. (2020), SOIL CHEMISTRY 5^th edition, Wiley.

Teaching methods

The course is divided into three parts:

1. Frontal lessons: through didactic unit explanations, students should gain knowledge of the main instruments available on key topics of soil chemistry and carbon cycle.

2. Seminars: invited speakers will hold seminars on key topics of the course. At the end of each seminar an interactive activity (peer instruction) will be carried out with the aim of stimulating discussion and strengthening the understanding of the topics covered during the seminar.

3. Exercises: Individual and/or group exercises will be held in the classroom. During the exercises, practical tasks on key topics of the course will be assigned to be solved individually or in group.

Assessment methods

Assessment will be based on performance in the participation at in-class activities (seminars, exercises) and a final oral examination.

The final examination consists in a technical conversation on the course contents. In this occasion, the teacher will also ask two questions aiming at the verification of knowledge acquisition about the theoretical part of the course. The final exam will last approximately 20 minutes.

The final quotation of the course "Low impact and recycling" will be the mean of this quotation “Plant nutrient management and recycling in agriculture ” and that obtained for the course of "Low impact farming".

Teaching tools

Class lectures and seminars also through remote platforms (e.g., Teams), depending on the status of the Covid-19 epidemics.

Lectures and exercises with specific softwares in the computer lab or through remote platforms, using students’ own computers.

Office hours

See the website of Marco Grigatti