Nutrient Cycling in Natural and Managed Ecosystems

CSS 672, 3 credits

Requirements: CSS 260, 372, NTRES 321, BIOEE 478 or equivalent, advanced knowledge of biological and chemical processes are beneficial

Short description

Building on knowledge of physico-chemical and microbial nutrient transformations and exchange processes in soil, we will study the pathways of nutrients in ecosystems from the rhizosphere to the landscape level. We will include both natural and anthropogenic ecosystems, working with case studies from tropical and temperate environments. An important aspect will be the understanding of environmental impacts by agriculture, forestry and agroforestry and the development of sustainable landuse systems. We will explore various tracer methods for the study of nutrient cycling including stable and radio-isotopes as well as rare elements and biomarkers. You will expand your knowledge in discussion groups and through presentations and work in-depth on a project which involves both field and laboratory experimentation. The results of the project will be presented in a poster conference.

 

This course is designed for all students:

· who want to advance their knowledge on nutrient forms in soil in the context of the nutrient cycling in landuse systems.
· who are interested in the biogeochemistry of nutrient elements of a broad array of ecosystems from agricultural fields, pasture, secondary to primary forests.
· who intend to further their knowledge about advanced methods in soil ecological work including isotopes.
· who are interested in field-based experimentation.
· who plan to do their thesis research or future work related to nutrient cycling.

 

Course Description

The course targets graduate students, who intend to expand their solid knowledge about processes, properties and dynamics of nutrients and organic matter in soil to the biogeochemical cycling of nutrient elements in natural and managed ecosystems. Nutrient transformations and fluxes between soil pools and between the atmosphere, vegetation, and ground water will be examined. Special attention will be paid to the interaction of vegetation components in the soil ecosystem. We will cover a diverse array of terrestrial ecosystems and discuss the nutrient cycles in natural forest and grassland ecosystems, the impact of natural and anthropogenic disturbance on nutrient cycling and compare those to agricultural systems including pollution with nutrients in watersheds. This course follows an experiential learning approach, where students develop independent projects, present a research proposal and conduct field research which concludes with a presentation and paper in publishable format. The experimental field work will be done in a landscape catena from natural forest to plantation forest to agricultural fields, and includes measurements of the main nutrient cycles such as litter fall, decomposition, stemflow, throughfall, leaching in the soil, and nutrient uptake by plants. In a lecture module, basic principles of nutrient cycles in soil and the interfaces to the atmosphere, vegetation and groundwater will be covered (seven 50-minute periods) as well as concepts of ecosystem analysis discussed (eight 50-minute periods). In a seminar module, students develop and present their research proposals, as well as report the results from their experimentation (fifteen 50-minute periods). In the laboratory module, students set up experiments, collect and analyze samples.

Course Contents

The course has several phases
Lecture
Presentation of Research Proposals
Field Research (including a short oral presentation and poster)
Guided Discussion Groups

Lecture

The goal of the lecture part of the course will be to introduce you to the basic information and principles of nutrient cycling in soil and in different terrestrial ecosystems, as well as highlight environmental aspects:

The nutrient cycle in soil ecosystems Nutrient transformations between soil pools Nutrient fluxes in soil Root activity distribution and nutrient uptake from soil Above ground nutrient flows in vegetation Fluxes of nutrients to the atmosphere Nutrients and the environment Nutrient interactions of plants in natural and managed ecosystems Nutrient emissions, pollution and climate change Impact of air pollution on the nutrient cycle Pollution of watersheds with P and N from agricultural fields

Field Experimentation

Possible topics:
1. Importance of throughfall, stemflow and litterfall for nutrient recycling in contrasting ecosystems
2. Spatial distribution of nutrient return to soil in tree ecosystems
3. Above- and belowground nutrient stocks in different ecosystems
4. Dynamics of nutrient release from litter in different ecosystems
5. Nutrient release from litter and soil nutrient availability
6. Root activity distribution of trees and crops
7. Leaching of nutrients in forested and ploughed soil
8. Biological N2 fixation and N transfer from legume to non-legume

Guided Discussions

Possible topics:
1. Isotopic approaches to organic matter and nutrient dynamics in soil: P mineralization/N dynamics/S pollution
2. Isotopic and mass approaches to biological nitrogen fixation
3. Characterization of dissolved organic nutrient forms in ecosystems
4. Measurements of root turnover and distribution
5. Measurement of root activity and root nutrient uptake
6. Field determinations of gaseous N losses
7. Nutrient leaching in soil
8. Modeling of nutrient cycling in ecosystems

 

Grading

Point distribution:
Presentation of proposal (group score) 200
Presentation skills (individual score) 150
Written Proposal 250
Guided discussions 150
Poster Presentation 250
Total 1000

The grade will be based on the following scale:
1000 to 900 points (100 to 90 %) = A
899 to 800 points (89.9 to 80 %) = B
799 to 700 points (79.9 to 70 %) = C
699 to 600 points (69.9 to 60 %) = D
below 600 points (below 60 %) = F