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02. AGROECOSYSTEM CONCEPT

� What is an ecosystem, and how can we study one?

� Is the earth an open or closed system with respect to energy and elements?

� How do we define "biogeochemical cycles," and how are they important to ecosystems?

� What are the major controls on ecosystem function?

� What are the major factors responsible for the differences between ecosystems?

The concept of the agroecosystem is

based on ecological principles

NATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMSNATURAL ECOSYSTEMS

Mineral/materi

Gen Sel Organ Organisme Populasi Komunitas

Sel

Sistem

Organ

Sistem

Organisme

Sistem

Populasi

Sistem Ekosistem

Gambar. Spektrum Ekologi

Organization of Life

Organisms

Populations

Communities

Ecosystems

Biosphere

BiosphereBiosphere

Ecosystems

Communities

Populations

Organisms

Scales of Ecological Organization

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INDIVIDU?POPULASI ?

KOMUNITAS ?

A

B

C

INDIVIDUAL ORGANISM

OrgansTissuesMolecules Cells Organs

systems

Concerned :how is a organism response the environmental factors?

How is a individual organism tolerance to stresses in environment where it will live?

Autecology/Physiological ecology Organism

POPULATIONS

� A population is a group of individuals of the

same species inhabiting the same area at

the same time.

� Important characteristics:

○ Population size, density, and dispersion

○ Birth and death rates

○ Growth rates

○ Age structure

○ Genetic Diversity

Characteristics of Populations

1. Population size,

density, and

dispersion

2. Birth and death rates

3. Growth rates

4. Age structure

5. Genetic Diversity

POPULATIONS

� Concerned :

Important in determining the factors that control population size and growth

relation to the capacity of the environment to support population over time

Population ecology

Population Ecology

� A population is a group of plants, animals, or other organisms, all of the same species, that live together and reproduce.

� The important of population ecology

1. Numbers of individuals in a population

2. Population dynamics: how and why those numbers increase or decrease over time

3. Population ecologists try to determine the processes common to all populations

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Population Ecology in Action

� Biologists in applied disciplines such as

� Forestry

� Agronomy (crop science)

� Wildlife management

� Must manage populations of economic

importance

� Prevent threatened or endangered species

from extinction

COMMUNITIES� Communities an assemblage of populations

of many species living together in the same

location at the same time.

� The important thing :

1. Community structure and functioning

2. Community Biodiversity

○ Number and types of species

○ Relative abundance of species

○ Interactions among species

3. Community Development

○ Community resilience to disturbance

○ Nutrient and energy flow

COMMUNITIES

Community ecology

� Concerned :

How the interactions of organism affect the distribution and abundance of the different species

ECOSYSTEMS

� Ecosystems are composed of all the communities and their physical, chemical, and biological processes.� Ecosystems sustain

themselves entirely through energy flow through food chains, and nutrient recycling.

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Kedung

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Pandan

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Beru

Rek esan W etan

Rek esa n Kulon

Cangar

Gi ntung

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P rumb ung

Brau

Clak et

Tala ngs ari

Ngebruk P agersa ri

Prambatan

P agergu nung

Kapr u Kandanga n

Selekta

Sidorejo

Sumb erbran tas

Gabes

Junggo

Gerdu

Kek ep

Tegalsari

Sengonan

Paya n

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Gem bol

Sikorembug

Tinjomoyo

Santri an

Sum bersar i

Pes antren

Pes anggrahan

Wun ucari

Srebet Barat

Plam boyan

Tambuh

K lum us an

Ngemul

Nga gl ik Ut ara

Meduran

Kali putih

Leban

Krajan

Kajar

Banar an

Gem ulo

Ta langr ejo

Gondang

Segu ndu

P unten

Tonggolari

Sumberejo

Srebet Timur

S onggo kerto

Ngagl ik Selata n Krajan

B umiaji

Ngudi

Dadaptulis Utara

Ngandat

J eding

Rejoso

Tlekung

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Dresel

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Kam punganyar

Temas Barat Putuk

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Temas

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li B

ranta

s

DESA TULUNG REJO

KEL. TEMAS

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DESA BUM IAJI

DESA PANDANREJO

KEL. SI SIR

DESA BULU KERTO

DESA SUM BERGONDO

DESA BEJI

DESA TAWAN GARGO

KEL. NGAGLIK

DESA GUN UN GSARI

DESA TORONGREJO

DESA ORO-O ROOMBO

DESA PANDESAR I

DESA J UNR EJO

KEL. SO NGG OKERTO

AREAL KEHU TANAN

DESA S IDO MULYO

DESA PASANG GRAHAN

DESA MOJ OREJO

DESA SUMBEREJO

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PETA LANDUSE TAHUN 2006 DI SUB DAS BRANTAS HULU

2000 0 2000 4000 Meters

U

TB

S

Landuse:: Hutan Alami: Hutan Produksi: Hutan Reboisasi: Lahan Terbuka: Pemukiman: Perkebunan: Rumput: Sawah: Semak: Tegalan

Example:

In Watershed

ABIOTIC COMPONENTS BIOTIC COMPONENTS

Sunlight Primary producers

Temperature Herbivores

Precipitation Carnivores

Water or moisture Omnivores

Soil or water chemistry (e.g., P, NH4+) Detritivores

etc. etc.

All of these vary over space/time

Components of Ecosystem

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The biosphere is the

global sum of all

ecosystems. It can also be

called the zone of life on

Earth. From the broadest

biophysiological point of

view, the biosphere is the

global ecological system

integrating all living beings

and their relationships,

including their interaction

with the elements of the

lithosphere, hydrosphere

and atmosphere

Biosphere Structural Properties of Communities

� Species Diversity

� Dominance and Relative Abundance

� Vegetative Structure (ex: grassland,

forest )

� Trophic Structure

� Stability

Figure. Relationships within an ecosystem

NATURAL ECOSYSTEMNATURAL ECOSYSTEMNATURAL ECOSYSTEMNATURAL ECOSYSTEM

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Processes of EcosystemsProcesses of EcosystemsProcesses of EcosystemsProcesses of Ecosystems

How ecosystems function:

1. Ecosystems have energy flows and

ecosystems materials cycles.

2. Ecosystems have nutrient cycles

Figure. Energy flows and material cycles.

1. Energy flows1. Energy flows1. Energy flows1. Energy flows and materials materials materials materials cyclescyclescyclescycles

Figure. Relationship between energy flow and nutrient cycle

2. Energy flows2. Energy flows2. Energy flows2. Energy flows and nutrient nutrient nutrient nutrient cyclescyclescyclescycles

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Biochemical Biochemical Biochemical Biochemical cycles in ecosystemcycles in ecosystemcycles in ecosystemcycles in ecosystem

1.

2. The carbon cycle

3. The phosphorus cycle

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AGROECOSYSTEMAGROECOSYSTEMAGROECOSYSTEMAGROECOSYSTEM

AGROECOSYSTEM VS. NATURAL ECOSYSTEM AGROECOSYSTEM VS. NATURAL ECOSYSTEM AGROECOSYSTEM VS. NATURAL ECOSYSTEM AGROECOSYSTEM VS. NATURAL ECOSYSTEM

� Natural ecosystem is closed, or at least, unmanaged ecosystem� Closed ecosystem—all elements recycled through ecosystem—

not often pure closed ecosystems anymore—humans frequently involved

� Agroecosystem is an open ecosystem, or managed ecosystem:� Producer moves plants, animals, environmental factors

(fertilizers, feed) in & out of ecosystem

� Will not continue on its own without management

� If left alone, would progress toward closed ecosystem, but probably not the same as original ecosystem before agriculture without human input again

Characteristics Agroecosystem Natural Ecosystem

Productivity High Low

Species diversity Low (monoculture)—can use crop rotation and

intercropping to stabilize more

High

Genetic diversity within species

Low High

Plant life-cycles present

Few All, more perennial

Competition Negative Tolerable (ecological niche)

Flowering, plant maturing

Synchronized Seasonal

Nutrient Cycles Open Closed

Permanence Short Long

Human Control High Low

Ecological Maturity Early, immature Mature, climax

ENERGY FLOWENERGY FLOWENERGY FLOWENERGY FLOW

Figure 2.7 Functional components of an agroecosystem.

Crop Populations Natural Plant Population(also true of weeds)

Seed brought in by producer Seed produced mostly by local plants

High seed viability Variable seed viability

Uniform seed dispersal Non-uniform seed dispersal

Low dormancy, carryover of seed

Possibility of dormancy, delayed germination (carryover)

Uniform soils Variable soil types

Uniform population age, genetics

Diverse population age, genetics

Even spacing within species Variable spacing within species

High allocation of plant resources to reproduction (seed)

Allocation to seed production may be lower

POPULATIONPOPULATIONPOPULATIONPOPULATION REGULATING MECHANISMREGULATING MECHANISMREGULATING MECHANISMREGULATING MECHANISM

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NUTRIENT CYCLING

AGROECOSYSTEM

� Inputs:Plant residueAnimal wastesAnimal residueAtmosphereNitrogen fixation

� Outputs:Plants� animals grazing on plantsDenitrificationRun-offleaching

NATURAL ECOSYSTEM

� Using the soil as a pool of nutrients:

� Inputs:FertilizersCrop residues AtmosphereNitrogen fixation

� Outputs:Crops � then removal from areaErosionLeaching

� Run-off

ASSIGNMENTASSIGNMENTASSIGNMENTASSIGNMENT

1. Cari contoh suatu ekosistem . 2. Tuliskan semua komponen yang ada di

dalam komunitas tersebut3. Jelaskan proses yang terjadi di dalam

komunitas tersebut