introduction into urban agriculture and agronomic aspects of organic waste reuse eawag peak course...
Post on 24-Dec-2015
217 Views
Preview:
TRANSCRIPT
Introduction into urban agriculture and agronomic aspects of organic waste reuse
EAWAG PEAK Course
Dionys Forster
Duebendorf, June, 2005
2
• Introduction into urban agriculture– Definition
– Objectives
– Processes
• Characteristics of urban agriculture in Cuenca, Dakkar, Dar es Salaam, and Hanoi (Video)
• Agronomic aspects of waste reuse– Plant growth and soil fertility
– Crop nutrient requirements
– Integrated soil fertility management
– Simplified nutrient balance
Con
tent
s
3
• Demographic growth and increase in urbanisation – challenges of the next decade!
Intr
oduc
tion
World’s population living in the cities
- 1994 about 45%
- 2025 about 65%
(x 10)
Urban population living in cities [billion]
0
2
4
6
8
10
1994 2025 Urban Pop World Pop
Introduction into urban agriculture
4
Poor people in % of total urban population in in dev. countries
0
10
20
30
40
50
60
1988 2000
Poor people in urban areas
- 1988 about 25%
- 2000 about 56%
• About 90% of urban growth takes place in developing countries!
Intr
oduc
tion
5
• Urban agriculture (UA) can contribute to mitigating the problems in Third World cities – poverty and waste management!
• Today, roughly 800 million people are involved in UA– 200 million produce for the public market
– 150 million are full-time employees
• Main objectives are– food security
– poverty alleviation
– public health
– sustainable recourse management
Intr
oduc
tion
6
• Agricultural processes are – agricultural practices
– soil quality management
– irrigation
– animal feeding
– public health management
– urban policy and planning
• Products of UA are– food/ non-food products
– money
– compost
– emission
– health impact
– etc.
Intr
oduc
tion
7
Intr
oduc
tion
Definition of urban agriculture
• Urban agriculture comprises the production, processing and distribution of a diversity of foods (e.g. vegetables and animal products) within intra- and peri-urban area.
• Main motivation is food production and higher income.
8
Food security
• Definition: All people have access to enough food at all time for an active and healthy life.
• Why food security?– most of food is required by households
– dependence on market systems and
processed foods
– balancing the food diets
Intr
oduc
tion
Food security depends very much on employment and income!
9
Food security (cont.)
• UA rises especially the food security of low-income residents and vulnerable groups
• Farming households are better off in terms of– energy and protein
– vitamins (vegetable consumption)
• Vegetable supply through urban agriculture
Intr
oduc
tion
Hong Kong Karachi
Dakar
UPA
RA
Hong Kong Karachi Dakar
45 % 50 % 70 %
10
Poverty alleviation
• Production of food products generates– real income through product sales
– fungible income through substitution of market goods by self-produced food products
• Saved money can be spent for other basic needs or invested in businesses.
Intr
oduc
tion
Poor women can improve their household finances through UA activities!
11
Poverty alleviation (cont.)
• The opportunity to acquire healthy food is decreasing for urban poor and middle-class families– structural unemployment
– currency devaluation
– inflation
– no subsidies
Intr
oduc
tion
Food expenditure compared to income (%)
0102030405060708090
100
1 Food Income
• UA belongs to the informal economy (no contribution to GDP)
12
Public health
• Public health is aiming to – promote the well-being
– prevent diseases and disabilities
– enhancing quality of life
Intr
oduc
tion
RessourceManagement
Food security
Physical work
Clean air
Public Health
13
Sustainable resource management
• Deploring urban environmental
conditions in cities of DC
• Serious urban environmental
problem: Urban waste!
• Common attitude: Cities focus on getting rid of their waste and fail to recognise its economic asset!
• UA has a considerable potential for – improved water management trough wastewater use– closing the nutrient loop through reuse of organic waste– reducing the daily flow of food into cities, thus saving fossil fuelIn
trod
uctio
n
14
Characteristics of urban agriculture in Cuenca, Dakkar, Dar es Salaam, and Hanoi (Video)
Cha
ract
eris
tics
of U
A
15
Agronomic aspects of waste reuse (i)
• Farmers’ main interest is to produce food and non-food products for subsistence or market selling
• Farmers’ focus is on good plant growth and high yields
What are the main factors influencing plant growth?
Agr
onom
ic a
spec
ts
16
Growth factors are energy (light, warmth), carbon-dioxide, water, and soil and soil fertility including different types of nutrients.
Agr
onom
ic a
spec
ts
17
Nutrients for growth
Agr
onom
ic a
spec
ts
Mother Rock
Superficial soil layer with organic matter
Tree with roots to the mother rock
Nutrient uptake
18
Organic matter
- Vast array of carbon compounds in soil- Created by plants, microbes, and other organisms- Living and dead plants and organisms
Agr
onom
ic a
spec
ts
19
Agr
onom
ic a
spec
ts
quickly available for plant growth
Soil organic matter in virgin soils
20
Effect of organic matter on soil properties
Organic matter improves all properties of the soil:
- Nutrient recycling is improved- Organic matter and clay form compounds that can store
nutrients- Micro-organism development is better - The water dynamics is positively influenced
- Soil water is stored over a longer time period
- Water infiltrates easier
- Soil water evaporation is reduced
Agr
onom
ic a
spec
ts
21
Organic matter improves further
- The formation of water resistant aggregates
- Reduces crusting, compaction
- Increases the number of soil pores and facilitates the exchange of gases
- Creates better conditions for root development
Other effects:
- Phytosanitary effect (depression of pests, diseases)
- Chemicals break down easier
Agr
onom
ic a
spec
ts
22
Nitrogen - the most important plant nutrient
Nitrogen fixation through bacteria
Decomposition and mineralisation
Atmospheric N-fixationNitrogen fixing
legume
Agr
onom
ic a
spec
ts
23
Organic matter: Soil organic matter and nitrogen function
- Strong influence of organic matter on soil organic matter in semi-arid regions
- 86 % of nitrogen used by plants comes from soil organic matter
- Type of crop and crop residues influence strongly the content of carbon in the soil and thus also the content of nitrogen
Agr
onom
ic a
spec
ts
24
Function of N-P-K in the plant
Agr
onom
ic a
spec
ts
Element, Compound
Function Symptoms of deficiency
Nitrogen
(N)
Element for N-compounds like proteins, vitamins, chlorophyll photosynthesis
Plant development disturbed, yield reduced, reduced tillering
Phosphorus
(P2O5)
Important for protein compounds
Disturbed growth, root development and tillering is reduced, flowering and maturity is slowed down
Potassium
(K2O)
Activator of enzymes, controls the water household in the plant
Slowed down carbon- hydrate and protein production, bad tasting fruits
25
Agronomic aspects of waste reuse (ii)
• Farmers’ main interest is to produce food and non-food products for subsistence or market selling
• Farmers’ focus is on good plant growth and high yields
• Main factors influencing plant growth
What is the nutrient demand of specific crops and how can this demand be satisfied?
Agr
onom
ic a
spec
ts
26
Crop nutrient requirements
• Crop specific fertiliser norm
• corrected with:- Natural factors (mineral particles, air, water, organic matter)
- Physical factors (texture, particle size, distribution, structure, compaction, soil depth)
- Chemical factors (nutrient contents, form and availability, storage capacity)
- Biological factors (organic matter, microbial biomass, CO2, O2 production, potential for N mineralisation)
Crop nutrient requirement
Agr
onom
ic a
spec
ts
27
Crop-specific fertiliser application norms
Agr
onom
ic a
spec
ts
Type of crop Norm yield
[t/ha]
N
[kg/ha]
P2O5
[kg/ha]
K2O
[kg/ha]
Cotton 4 250 175 125
W-Wheat 6 140 65 95
S-Wheat 5 120 55 90
Maize 8 110 95 240
Potatoes 45 120 90 400
Sunflower 3 60 60 400
Tobacco 2 60 90 70
Alfalfa (silage) 45 150 150 70
Mung beans 3 0 70 145
28
Integrated Soil Fertility Management: Optimal use of different nutrient sources and protective measures
Agr
onom
ic a
spec
ts
Compost
Farmyard Manure
Green Manure
Crop residues
Crop
Mineral fertiliser
Agro-technical measures
Urban organic (liquid/solid)
waste
29
Organic Fertilisers
Organic Fertiliser N
[kg/t]
P2O5
[kg/t]
K2O
[kg/t]
Cotton stems and dung compost 4 1.3 14
Vegetable waste compost 4.9 1.2 9
Garden compost 4 3 2
Cow manure 12 7.5 18
Sheep manure 10 6 14
Pig manure 6 3.5 3
Poultry (chicken) manure 20 25 14
Human urine 170 38 38
Human faeces 60 42 18
Nightsoil (fresh) 118 39 28
30
Organic fertiliser supplemented with mineral fertilisers
Agr
onom
ic a
spec
ts
31
Nutrient budget/balance at field level
Agr
onom
ic a
spec
ts P
Field
KPN N
KInflows Outflows
32
Nutrient budget/balance at farm level
Agr
onom
ic a
spec
ts
Field 2
InflowsOutflows
Field 1
InflowsOutflows
Inflows Outflows
Field 1Field 2...
Field 1Field 2...
33
Simplified nutrient balance calculation
- Simple method
- Rough estimation of the crop nutrient requirements
- Needs only few information- Crop requirements
- Obtained crop yield
- Amount and content of available fertilisers
- Correction of crop nutrient requirements
Agr
onom
ic a
spec
ts
34
Example: Calculation of the nutrient balance on the field level
A farmer...
- has 1 cotton field of 2 ha size- has usually a cotton yield of 1.8 t/ha- bought 36 tonnes of compost (0.4% N, 0.1% P, 0.9%
K) - uses for complementary fertilisation:
- Ammonium-phosphate (18% N, 55% P)
- Ammonium-nitrate (34% N)
Agr
onom
ic a
spec
ts
35
Calculation of the nutrient balance on the field level
Agr
onom
ic a
spec
ts
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm
Farmyard manure/ compost
Difference = mineral fertiliser
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]N : P : K
Ammonium-phosphate
(18 %, 50 %)
Ammonium-nitrate (34%)
36
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost
Difference = mineral fertiliser
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]N : P : K
Ammonium-phosphate
(18 %, 50 %)
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
37
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]N : P : K
Ammonium-phosphate
(18 %, 50 %)
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
38
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser 41 61 -106
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]N : P : K
Ammonium-phosphate
(18 %, 50 %)
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
39
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser 41 61 -106
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]
0.67 : 1 : 0N : P : K
Ammonium-phosphate
(18 %, 50 %)
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
40
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser 41 61 -106
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]
0.67 : 1 : 0N : P : K
Ammonium-phosphate
(18 %, 50 %)0.36 1 0
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
41
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser 41 61 -106
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]
0.67 : 1 : 0N : P : K
Ammonium-phosphate
(18 %, 50 %)0.36 1 0 122 244 22 61
Ammonium-nitrate (34%)
Agr
onom
ic a
spec
ts
42
Calculation of the nutrient balance on the field level
Type of Crop: Cotton Yield Amount applied
Nutrients
[kg/ha]
Field size 2 ha t/ha t/ha Field [t] N P2O5 K2O
Fertiliser norm 4 250 175 125
Corrected norm 1,8 113 79 56
Farmyard manure/ compost 18 36 -72 -18 -162
Difference = mineral fertiliser 41 61 -106
Type of mineral fertiliser
Nutrient ratio kg/
haField [kg]
0.67 : 1 : 0N : P : K
Ammonium-phosphate
(18 %, 50 %)0.36 1 0 122 244 22 61
Ammonium-nitrate (34%)
-- -- -- 65 130 22
Agr
onom
ic a
spec
ts
43
Calculation of the nutrient balance on the farm level
Inflows Outflows
Field code N P2O5 K2O N P2O5 K2O Field code
Field 1 50 20 30 84 39 63 Field 1
Field 2 100 20 35 188 131 94 Field 2
Field 3 40 15 25 69 59 150 Field 3
Total inflows 190 55 90 341 229 307 Total outflows
Deficit 151 174 217 - - - Surplus
Total balanced 341 229 307 341 229 307 Total balanced
Agr
onom
ic a
spec
ts
44
Summary
• Urban agriculture comprises the production, processing and distribution of a diversity of foods (e.g. vegetables and animal products) within intra- and peri-urban area.
• Four main objectives: food security, poverty alleviation, public health, sustainable recourse management
• Farmers’ focus is on good plant growth and high yields to produce food and non-food products for subsistence or market selling
• Integrated soil fertility management makes use of various nutrient sources and agro-technical measures
• The simplified nutrient balance calculation allows a rough calculation of the nutrient balance based on an estimation of the crop nutrient removal
top related