Soil Science 1 2 2006 Rua Cambodia

Dr. Jan-Peter Mund (PhD Geographer)Faculty for Land Management and Land AdministrationRoyal University of Agriculture, Phnom PenhUniversity of Bonn and Mainz, Department of Geography, Germany

Soil Sciences Soil Sciences An Introduction to the ecosystem below usAn Introduction to the ecosystem below us

2006 2Integrated Expert: Dr. Jan-Peter Mund (PhD Geographer)

Content of the lecture on Soil Science

Introduction – Who is the teacher and What is learningWhat is a soil - Ecosystem and limited natural resourceSoil physics – Content, Structure, Fraction, Layers etc.Soil chemistry – Soil color, ph-Value, Soil organic matterSoil processes – Development, Weathering, FormationField practice in the surrounding of RUAWritten Test (1 hour)Soil fertility and organic matterSoil biology and biochemistry Soil as a source of plant nutrientsSoil survey and Soil classification methods Field practice Soil science in environmental managementSoil classifications and Soil regions of the world

Final exam


Content of the this lecture

1. Introduction2. Teaching method in this lecture3. What is learning ? - Background of

the learning and knowledge cycle

Question and answers – Break

4. What is a soil ?

5. General Introduction to the soil ecosystem


Introduction – Who is the teacher

My name is Jan-Peter Mund, please call me Jan.PhD Geographer (physical geography, geology, botany)Not married, no kids, living with my partner in Phnom P.University lecturer for physical geography, ecology and soil sciences.Expert in: Soil survey, GIS and mapping, Living in Cambodia since November 2003. Working as gtz/CIM advisor at the RUA (FLMLA).15 years research, teaching and working experience in developing countries in Africa south of the Sahara.Hobbies: Sports, travelling to foreign countries, music, literature and modern theatre.


How I am going to teach this lecture

In English and sorry, not in KhmerEvery Wednesday afternoon in the classroom from 13:00 to 14:30 and from 14:45 to 16:00In a friendly and open minded atmosphereWith powerpoint presentations and field practise With open questions to the students during the lecturePlease ask me every expression you do not know !With open student discussions in the classWith questions and answers to check the student‘s learning progressAs a cognitive experimental learning processIn a way that you learn how to learn !


What is the position of the teacher or trainer in the learning process

A teacher is someone who knows something and do not know a lot of other things.He knows exactly what he really knows and he knows well, what he do not know.That means, he knows where his know-ledge leaves off and is honest about it. A good teacher is able to explain what he knows and can motivate students to learn what they should know. The teacher has to be asked by the students for more detailed explanation, if they do not understand him. By the way, he increases the student’s active and passive knowledge of scientific matter and other subjects and things.


What is learning as a process

Why learning is so important ?

The ability of any nation to compete successfully in a global market today

depends on the scientific, mathematical and critical literacy of its citizens.

The real voyage of discovery and learning consists not in seeking new landscapes

but in having new eyes.(Marcel Proust)


What is learning as a process

What is learning ?Learning is the basic process of behavioural change.Learning is more than only repeating !It is a relatively permanent change in an organism’s behaviour due to experience and information.This ability to become increasingly more effective in solving problems as more problems are solved.Your task is now: To learn how to learn !


The Experiential Learning Process

The "learn-by-doing" approach allows students to experience something with minimal guidance from the teacher.

Instead of being told "the answers," they are presented with a question, problem, situation, or activity which they must make sense of for themselves.

Learning by doing is called "experiential learning" because it is based on learning from experiences.


The importance to ask questions !

Asking Questions: One of the most important roles of the teacher is to stimulate students to think about.

"Why?" and "How?" and "What if?“.

Asking open-ended questions along the way helps students to think about the problem.

This also provides opportunities to evaluate their experience and progress.


The Experiential Learning Process

This is learningby doing

Experiencing

ReviewingPlanning

ConcludingDeciding

Implementing


What is research? - A circled process

Find asolution

Review the problemtogether withthe solution

Recognizea problem

Understand the problem

Choosethe method

Analyze thequestions

The circle of research andunderstanding


Learning can be hard - We need a break !

15 Minutes break

And than we continue with the following points:

4.What is a soil ?

5.General Introduction to the soil ecosystem


Introduction - What is a soil ?

HabitusHabitus and Field surveyand Field survey Analytical workAnalytical workDescriptionDescriptionPresentationPresentation

Soil is a complex mixture of mineral matter, organic matter and living organisms.

For many years, soil was considered simply the loose fraction of the Earth's crust. It was around 1880, that soil was recognized as a natural body for the first time by the Russian scientist Dokuchaev.

Field Field


Introduction – Content of the 2nd part

What is a soilSoil definitions and viewpointsFactors and processes of Soil DevelopmentSoil horizonsSoil profileSoils – a limited resource in danger !Factors of Soil Degradation worldwide


What is a soil ?


We Study Soil Because It's A(n)

Great integratorMedium of crop production

Filter of waterand wastes

Producer and absorber of gases

Home to organisms (plants, animalsand others)

Medium for plant growth

Snapshot of geologic, climatic,biological and

human historySource material for construction, medicine, art, etc.

Essential limited natural resource of the earth

Waste decomposer


How a soil looks like ? Some pictures

What is the color of these soils ?And why they have these colors ?

Red soil light brown dark brown


Soil is a complex mixture of mineral matter, organic matter and living organisms.Soils develop over time, sometimes very slowly in dry desert areas or more quickly in wet tropical regions.Many of our soils have been developing since the last 1 Mill. years and some others like lowland soils during the last 10 thousand years.The soil is different from "powdered rock" or "dirt" in that it supports life; in particular, the growth of plants.Soil can be thought of as the "skin" of the land; without it the land would die.Soil is in a dynamic equilibrium. It is always changing as a result of its interaction with the environment.

What is a soil ? - Definition


Soils are a complex three phase system composed of solids, liquids and gases with . The study of thephysical behavior of these phases is called SoilPhysics and includes::

Density and porosityTexture and structureColourWaterretention and movement

Soils are formed by weathering of "parent materials".These materials have many origins such as bedrock surfaces, marine (ozean), aolian (wind blown), lacustrine (from lake beds), alluvium (river) and organic (peat) deposits.

Definition of Soil phases


Soil horizons - Layer field analysis


Soil profile – Analytical Soil horizons


SoilSoil DevelopmentDevelopment

Factors of Soil Development

Characteristics

Processes

Soil colori.e. colorisation throughSi, Al, Fe, Mn

Soil structurei.e. grains, prisma or pillarstructure

Organic Matteri.e. Mikroorganismen, Pilze

Content of calciumor lime as a result of weathered bedrock

pH-valueneutral, basic oralcalic Soil fraction classes

Stone, Sand Silt Clay Transformation WeatheringPutrefaction.Soil Mineral depletionSoil Mineral regrowthClay mineral regrowthWeathering of organic matterDevelopment of the soil structure

Translokations processesUpdwelling of saltTranslocation of clayTranslocation of organic matterBio-TurbationTranslocation of Si, Al, Fe, und MnTranslocationthe of topsoil layer

SoilSoil TypeType

ReliefHuman beingsTime

Bedrock

Vegetation

climate

Factors and processes of Soil Development


Soil profile development


sandyDystricGleysol

Ap

Apg

Brg

Examples for soil research in the field


Catena A - less degraded -upper slope middle slope lower slope valley base

open tree savanna

Acrisol

no erosion

plinthicFerralsol

Cambisol

open to densetree savanna

densetree savanna

opentree savanna

shrubpatches

schematic soil depth

Complex Soil catena research on degradation


Catena B - degraded -upper slope middle slope lower slope valley basesingular trees

tussock grasses

no vegetationto

tussock grasses

closed dryforest patches

Leptosol

singular treestussock grasses

no vegetationto

open tree savannatussock grasses

shrubpatches

purerock

Leptosol

Leptosol

purerock

colluvialsediment

Ferralsol

rill and sheeterosion

colluvial sedimentation,gully erosionsevere sheet and rill rosion

schematic soil depth

Complex Soil catena research degradation

colluvialesHillwash-Sedimentüber Phlintosol

Soil erosion processes

Sheet- and rillerosion


Soils – a limited resource in danger !

Soil erosion in agricultural areas is one of the most dangerous trends worldwide.

Especially unadaptedagricultural land use systems as well as deforestation causes the major amount of yearly loss of topsoil in the inter tropical regions.

That leads a loss of more than 1.5 billion hectares of cropland worldwide.


13%

14%

49%

24%

AfricaAfrica67,4%67,4%

29%

7%

35%

28%

1%

WorldWorld

EuropeEurope27,3 %27,3 %

34%

22%

35%

9%

OzeaniaOzeania and and Australia 18,1%Australia 18,1%

15%

61%

18%2% 4%

AsiaAsia 39%39%

38%

6%26%

27%

3%North America 28,4%North America 28,4%

32%

61%

3%

4%

22%

18%

14%

45%

1%

Central Central America 74,1%America 74,1%

South AmericaSouth America46,2%46,2%

41%

27%

26%

5%

1%

Source: World Ressources Institut 1995: percentage of eroded area in total

DeforestationCutting of fuel woodOvergrazingAgricultureIndustrialization

Factors of Soil Degradation worldwide


Students‘ assignment for next ThursdayTo next week you have to describe with your own words three different soils that can see on that picture:


Thank you for your kind attention

let’s learn together more about the endangered soils of Cambodia

Technology

Soil Science 1 2 2006 Rua Cambodia