326 principles of ISFM powerpoint

Principles of Integrated Soil Fertility
Management (ISFM)

Africa Soil Health Consortium
2013

Introduction to ISFM as a concept


Objectives
• Understand the history of soil fertility management
• Understand why ISFM is needed for smallholder
farmers in sub-Saharan Africa
• Understand the individual components of ISFM and
their interactions with each other
• Understand the variability between farms and the
need for local adaptation of nutrient input
recommendations
• Understand the concept of agronomic efficiency
• Understand the concept of economic efficiency


History of soil fertility management
Approach: external
input use

Approach: organic
input use

Approach: organic
input use & fertilizer

Approach:
integrated soil
fertility
management

Fertilizer: +++
Organic inputs: -

Fertilizer: Organic inputs: +++

Fertilizer: +
Organic inputs: +++

Fertilizer: ++
Organic inputs: ++

Limited success,
shortfalls in
infrastructure and
farming systems

Limited adoption,
organic matter
production requires
land, labour and/or
livestock

Localized adoption
around specific

crops

Goal of large scale
adoption

1960s and 1970s

1980s

1990s

2000s


Focus on mineral fertilizer

Adding nutrients: The ‘Green Revolution’
• A success in Asia and Latin America

– External input use (mineral fertilizers & lime)
– Improved varieties
– Irrigation

• A disappointment in sub-Saharan Africa

– Fertilizer is ‘too costly’
– Fertilizer use is uneconomic in poorly responsive environments
– Fertilizer recommendations were not tailored to farmer’s
specific circumstances
• Heterogeneous soil fertility

• The farmer’s social and economic situation and goals


Focus on organic resources
• Conserving nutrients: through compost and manure
• Recycling nutrients : through deep rooting trees
• Adding nitrogen: through biological N2 fixation (BNF) by leguminous cover crops,
trees, shrubs and grain legumes
Disadvantages:
• Quality of organic resources is often poor
• Quantity of manure or organic resources is not sufficient
– Competing uses for plant residues

• Organic materials are bulky and costly to store, transport and apply
• Adoption and suitability of leguminous cover crops is limited by
(1) high labour requirements
(4) drought and low soil pH limit BNF
(2) only N can be supplied (5) lack of useable yield (grain
(3) availability of other nutrients (e.g. P)
legumes excepted)
need to be sufficient for effective BNF


When unsufficient nutrients are
added to maintain soil fertility:
downward spiral into a poverty trap
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Integrated Soil Fertility Management
‘A set of soil fertility management practices that necessarily
include the use of fertlizer, organic inputs and improved
germplasm combined with the knowledge on how to adapt
these practices to local conditons, aiming at optimizing
agronomic use efficiency of the applied nutrients and
improving crop productivity. All inputs need to be managed
following sound agronomic and economic principles.’

Yield = G (genotype) x E (environment) x M (management)


Principles of production ecology
Yield = G (genotype) x E (environment) x M (management)
Defining factors
YP = G x E
Limitng factors

YW = G x E x M (water)
Reducing factors

YA = G x E x M (water) x M (nutrients,
pesticides, weeding, etc)


Components of ISFM

Yield = G (genotype) x E (environment) x M (management)

Seeds should be adapted in terms of
•Responsiveness to nutrients (M)
•Adaptation to the local environment (E)
•Resistance to pests and diseases (E)


Components of ISFM

Yield = G (genotype) x E (environment) x M (management)
Mineral Fertlizers:
•
•

Supplement recycled or added
nutrients from organic sources
Contain essential nutrients in a
form readily available for plant
uptake.

Organic inputs:
•
•
•
•
•
•
•
•

Source of nutrients, including nutrients
not contained in mineral fertilizers
Replenish soil organic matter
Increase the crop response to mineral
fertilizer
Improve availability of phosphorus for
plant uptake
Regulate soil chemical and physical
properties
Create a better rooting environment due
to the improvemnet of the soil structure
Improve the soil’s capacity to store
moisture
Maintain the biodiversity in the soil


Positive interaction: fertilizer – organic matter

Yield (kg/ha)

With organic matter

Without organic matter
C

A

B

Fertilizer input (kg/ha)


Positive interaction:
fertilizer – organic matter

Long term effect of fertilizer and
crop residues on millet grain yield
in Sadore, Nigeria



Exercise
1. What can you conclude from this
figure?
2. What do you still have to take
into account before making
recommendations based on this
figure?

Effect of fertilizer (60 kg N, 13 kg P and 25 kg

K/ha from NPK (17:17:17 and urea) on grain
yield of 2 local and 2 improved maize
varieties in south Kivu, DR Congo.


1. All varieties had
larger yields when
fertilizer was applied
2. Highest yields with
fertilized hybdrids

4. Yield from
unfertilized BH540
was slightly higher
than fertilized local
varieties
3. Yields more than
doubled when both
fertilizer and improved
germplasm was used



Local adaptation

Variability between farms
Variability between farms
• Goals and objectives
• Importance of off-farm
income

• Amount of production
resources available to invest
in the farm
–
–
–
–
–

Land
Labour
Animal manure
Crop residues
Cash
Tittonell et al. (2008)


Local adaptation

Variability between fields
Soil fertility gradients
within farms:
-Fertile home fields
-Degraded outfields


Responsive
Responsive
(in-field)
(in-field)

Less-responsive
Less-responsive
(outfield, couch grass infestaton)
(outfield, couch grass infestaton)

Unresponsive
Unresponsive
(degraded
(degradedsoil)
soil)

Low or no response:
-Fertile in-fields, due to
high amounts of
nutrients applied in the
past
-Degraded soils
-Weed infested fields


Variable responses to nutrient inputs

Tittonell and Giller (2013)


The response to seed
and fertlizer inputs is
large in responsive soils
The response to seed and

fertlizer inputs is small in
unresponsive soils
Organic resources are
needed to make efficient
use of fertlizer and
improved seeds in
unresponsive soils


Agronomic efficiency (AE)
The amount of additional yield
obtained per kg nutrient applied

AE = (YF-FC) / Xappl
YF: Yield in treatment with
nutrient application
YC: Yield in control treatment
Xappl: the amount of nutrient X
applied (kg nutrient/ha)


Increasing AE
To increase AE (and yield) at a particular fertilizer
application rate:
•Plant the crop at the right planting density
•Apply fertilizer at the right time
•Apply fertilizer in the right place
•Apply fertilizer in several split applications

Sound agronomic principles
Maximum return to investments and high AE need
good crop management with:
•Appropriate varieties
•Appropriate land preparation
•Spacing
•Planting dates and practices
•Weeding
•Pest and disease management practices
•Appropriate intercropping arrangements


Sound economic principles
Comparing the value of additional yield with the costs of the inputs required