Title: Human impact on soils
Mentor: Salvatore Engel-Di Mauro

Background
Since the 18th century, soil quality changes have figured among the most significant alterations on the Earth's surface. The industrialisation and marketisation of agriculture, expanding (sub)urbanisation, and other such social process have brought changes in land-use and -cover that have affected soils to an increasingly global extent. These effects are systemic and cumulative, ranging from permanent losses due to sheet and gully erosion to leaching-related nutrient content declines for plants and soil biota.

Objective
This project aims to familiarise participants with different ways humans impact soil quality and with some of the techniques that can be used to assess human impact. An overview of general soil science principles and anthropogenic processes is followed by soil sampling and analysis on various soil types under different forms of land-use. Both field and lab techniques are applied to understand the human impact on soil quality, focusing on soil structure, pH, cation exchange capacity, and some macronutrient content measures. Participants are encouraged to gather soil samples from sites in addition to those visited during the meetings with the mentor.

The final portion of the project is dedicated to understanding how the impact on soils is socially uneven (how different people have different degree of impact related to political and economic power) and soil degradation affects people differently according to social position. The mentor will convey and discuss the results of his doctoral research and provide some readings that address such issues.

Principal question
The principal issue investigated regards distinguishing the acidification effects of nonhuman soil processes from those related to land-use. Acidification comprises the major theme of the field and lab exercises, but participants are encouraged to explore additional anthropogenic processes. Soil acidification has been identified as a major source of soil quality deterioration resulting from human impact. Processes such as high synthetic-input farming and residential development expansion are often linked with acidification.

Educational significance
From the point of view of environmental dynamics, the deterioration of soil quality is a more subtle process than logging, for instance; yet it is a major factor behind the reduction of vegetational cover (which also stabilises and develops soils) and the viability of crop production. Human impact on soil quality therefore has simultaneously a direct ecosystemic and societal effect that is often underestimated. The participants are expected to envisage practical solutions and policy suggestions regarding soil quality degradation, using available literature as well as the results from the field and lab investigations. The final web product should begin to delineate a main problem of soil quality change, what possible factors contribute to that change (both anthropogenic and nonhuman), the methods used to determine what soil quality change has occurred (e.g., sampling methods and pH determination), how anthropogenic effects have been identified and disaggregated, and what can be done to mitigate and/or prevent the particular soil quality deterioration investigated (e.g., acidification).

PowerPoint Presentation

Tentative schedule

6 July: Classroom, field, and lab
Overview of soil formation processes
Discussion of soil sampling methods and analytical techniques
Lunch
Field analysis of soil profile (horizon interpretation, texturing, colour determination, etc.)
Soil sampling on plot(s) to be determined
Introduction to lab and equipment
Overnight drying of extracted samples
Brief overview of lab techniques used in the project

10 July: Field and lab
Further soil sampling at designated plot(s)
Return to lab for overnight drying for extracted samples
Lunch
Review of soil chemical processes and soil-plant relations
Review of lab techniques
Mechanical analysis (bulk density, particle size, porosity)
Organic Carbon (OC)
pH

13 July: Lab
Mechanical analysis, OC, and pH for last batch of samples
Review of lab techniques
Discussion on social aspects of soil quality change
Lunch
Cation Exchange Capacity (CEC)
N, K and possibly P, Ca, Mg, and other macronutrients
Remaining project work

Links

 

Introductory material and teaching resources on soil science
American Society of Agronomy Education initiative K-16
Plant nutrient management (Prof. Barak, UW-Madison)

Soil science concepts and methods - teaching resources

Soil dynamics
Soil science web directory

United Nations Food and Agriculture Organisation

 

Soil acidification

Acidification and liming (Swedish Environmental Protection Agency)
Acidification processes
Anthropogenic soils

pH, fertilisers, and lime
pH modification for farming
pH problems

Soil testing (soil acidity and liming)

 

Soil survey information

Compendium of On-Line International Soil Survey Information
FAO soil surveys and databases

Soil Survey of Mercer County in New Jersey

USDA-NRCS National Soil Survey Center

 

Agricultural alternatives

Agroecology
Food First
Gender and agriculture plus related links

International Federation of Organic Agriculture Movement
The Center for Agroecology and Sustainable Food Systems
The Soil Association