This document outlines the objectives and content of a three-day training workshop on cascade water resources development and management. The training will explain key concepts including the nature and evolution of tank cascade systems in Sri Lanka, their important features, current status, and issues. It will also cover how to plan and manage water resources in cascades through community participation. One lesson will focus on agricultural ecosystems, comparing natural and agro-ecosystems, and describing the components, interactions, and sustainability of tank cascade-based agro-ecosystems. The overall goal is to equip participants with knowledge on developing and maintaining sustainable cascade systems.

1. Module Objectives:
After this training, the participants will be able to explain:
 The nature of Tank Cascade Systems in Sri Lanka;
 How the tank cascade system has evolved on dry zone landscape?;
 The important features of tank cascade systems;
 Present status of tank cascade systems in Sri Lanka;
 The contemporary issues found in cascade systems;
 What consequences and constraints experienced by village communities?;
 Why we need to plan water resources development in cascades?
 How we can prepare a water management plan for a cascade?
 Why we need participation of communities in cascade development and management? and
 Roles and responsibilities of implementing partners in cascade development and management
Three Day Residential Training Workshop on
Cascade Water Resources Development and Management
P.B. Dharmasena
Lesson 3 - Agricultural eco system of cascade

2. Lesson 3 - Agricultural eco system of cascade
Lesson 3 Objective:
After this training session, the
participants will be able to explain:
 What is an Ecosystem and an agro-
ecosystem; and
 The nature of the tank cascade
based agro-ecosystems in Sri Lanka

3. Lesson 3 - Agricultural eco system of cascade
CONTENT
Topic Description
1 Ecosystem principles Organization of life, diversity, connectivity, interaction,
complexity, knowledge, participation, management
2 Ecosystems in Sri Lanka Natural forest ecosystems, natural grass ecosystems, inland
aquatic systems, coastal ecosystems
3 Agro-ecosystems What is an agro-ecosystem?, Comparison of natural and agro-
ecosystems, nutrients recycling, special features of agro-
ecosystem
4 Tank-based agro-ecosystems Components, interactions, co-existence, soil and water resources,
recycling
5 Tank cascade based agro-
ecosystems
Natural components, human influence, management, sustainability
6 Discussion

4. Organization of life
Organisms
Populations
Communities
Ecosystems
Biosphere
Biosphere
Ecosystems
Communities
Populations
Organisms
1. Ecosystem Principles

5. 1. Ecosystem Principles Scales of Ecological organization

6. Individual, population, community and ecosystem
A
B
C
D
1. Ecosystem Principles

7. 1. Ecosystem Principles

8. connectivity, interaction and complexity of ecosystem
1. Ecosystem Principles

9. What you can learn from this picture?
1. Population
2. Genetic
diversity
3. Interaction
1. Ecosystem Principles

10. How do we take care of ecosystems?
1. Knowledge on
ecosystems
• Investigation
• Awareness
• Training
1. Ecosystem Principles

11. How do we take care of ecosystems?
1. Knowledge on
ecosystems
2. Participation in
ecosystem
activities
• Collective
efforts
• Individual
behaviour
• Participatory
ecosystem
management
programmes
1. Ecosystem Principles

12. How do we take care of ecosystems?
1. Knowledge on
ecosystems
2. Participation in
ecosystem activities
3. Management of
ecosystems
• Planning
• Implementation
• Maintenance
1. Ecosystem Principles

13. 2. Ecosystems in Sri Lanka

14. Ecosystems in Sri Lanka
• Forest and related ecosystems -
tropical forest types, riverine dry
forest, grasslands etc.
• Inland wetland ecosystems -
flood plains, swamps, reservoirs,
wet villus
• Coastal and marine ecosystems
- mangroves, salt marshes,
sand dunes and beaches,
lagoons and estuaries, coral
reefs
• Agricultural ecosystems - paddy
land, fruit cultivations, small
crop holdings or other field
crops, vegetables, export crop
plantations, home gardens,
chena lands
2. Ecosystems in Sri Lanka

15. 3. Agro-ecosystems

16. Property Agro-ecosystem Natural ecosystem
Productivity High Low
Species diversity Low High
Genetic diversity within species Low High
Plant life cycles present Few Whole, more perennial
Competition Negative Tolerable
Flowering, plant maturing synchronized seasonal
Nutrient cycles open closed
Permanence Short Long
Human control High Low
Ecological maturity Early, immature Mature (climax)
Comparison of natural and agro-ecosystems
3. Agro-ecosystems

17. NUTRIENT CYCLING
 Inputs:
Plant residue
Animal wastes
Animal residue
Atmosphere
Nitrogen fixation
 Outputs:
Plants animals
grazing on plants
Denitrification
Run-off
leaching
NATURAL ECOSYSTEM
AGROECOSYSTEM
 Using the soil as a
pool of nutrients:
 Inputs:
Fertilizers
Crop residues
Atmosphere
Nitrogen fixation
 Outputs:
Crops  then
removal from
area
Erosion
Leaching
 Run-off
3. Agro-ecosystems
Nutrients cycling

18. Special Features of Agro-ecosystem
3. Agro-ecosystems
• Productivity - the quantity of food, fuel or fiber that an agro-
ecosystem produces for human use.
• Stability - consistency of production.
• Sustainability - maintaining a specified level of production
over the long term.
• Equity - sharing agricultural production fairly.
• Independence – agro-ecosystem self-sufficiency.

19. 19
4. Tank-based agro-ecosystems
Components

20. Water
Rain
water
Surface
water
Ground
water
Drinking and
domestic water
Rain-fed
farming
Agro-well
farming
Tank irrigated
farming
Fishery
Homestead
farming
Livestock
4. Tank-based agro-ecosystems
Interaction

21. 4. Tank-based agro-ecosystems
Co-existence

22. Godawala
Perahana
Gasgommana
Iswetiya
Tank water resource – no pollution, no sedimentation: safe drinking water, good storage
4. Tank-based agro-ecosystems
Soil and water
resources,
recycling

23. Landa
Thisbambe
Gangoda Kattakaduwa
Kiul-ela
Paddy field soil resource - no salinity, good fertility: High productivity
4. Tank-based agro-ecosystems
Soil and water
resources,
recycling

24. • Natural components – forest,
shrub lands, natural streams,
habitats
• Human influence – tanks,
paddy fields, hamlets,
religious places
• Management – sharing water,
sharing lands, conjunctive
water use
• Sustainability – regulatory
measures, farming under
water stress, balance between
rain-fed and irrigated farming
4. Tank cascade - based agro-ecosystems
Natural components, human influence, management, sustainability