A. Castro1, M. Rivera1, O. Ferreira1, J. Pavón2, E. García1, E. Amézquita3, M.
Ayarza3, E. Barrios4, M. Rondón5, N. Pauli6, M.E. Baltodano1, B. Mendoza7, L.A.
Wélchez8, N. Johnson9, J. Rubiano10, S. Cook10 and I.M. Rao1
(1) CIAT; (2) Instituto Nicaragüense de Tecnología Agropecuaria (INTA), Nicaragua; (3)Corporación
Colombiana de Investigación Agropecuaria (CORPOICA), Colombia; (4)EMBRAPA, Brazil; (5)IDRC, Canada; (6)University of Western Australia; (7)Universidad Nacional de Agricultura (UNA), Nicaragua; (8) FAO-
Honduras; (9) ILRI, Kenya; (10)CPWF-Basin Focal Project Coordination, Colombia
Slash and burn (SB, Fig. 1) is a traditional form of agriculture practiced
by small-scale farmers in around 20% of the tropical land area (Dixon et
al., 2001). Despite the short-term benefits obtained from its use (i.e.
source of firewood, source of nutrients for crop development, and
reduction in incidence of pests and diseases), it is recognized as an
environmentally unfriendly practice that does not guarantee food
security and may lead to a rapid resource degradation. Unfortunately,
there are not many alternatives to SB agriculture, especially for small-
scale farmers usually forced to produce on marginal soils on sloping
lands.
In southwest Honduras, in the early 1990s experts from FAO identified
native farming practices and worked together with farmers to develop a
production system suitable to replace the SB system in that eco-region.
The Quesungual Slash and Mulch Agroforestry System (QSMAS, Fig. 2) is
a smallholder production system comprising a group of technologies for
the sustainable management of vegetation, soil, water and nutrients in
drought-prone areas of the sub-humid tropics. The system has been
adopted by 6,000 farmers in 7,000 hectares in Candelaria, Honduras,
due to its benefits including resilience even to extreme climatic events
such as El Niño in 1997 and hurricane Mitch in 1998 (FAO, 2005).
The main objective of this CPWF funded project was to define the key
driving forces and principles behind the social acceptance and the
biophysical resilience of QSMAS by determining the role of the
management components of the system and QSMAS’ capacity to sustain
crop production and alleviate water deficits on steeper slopes with high
risk of soil erosion. Research activities were conducted in Honduras
(reference site), Nicaragua and Colombia (validation sites) (Fig. 3), from
April 2005 to December 2008, to compare the following five land use
systems:
1= Slash-and-burn (traditional production system)
2, 3 and 4= QSMAS of <2, 5-7 and >10 years old, respectively
5= Secondary forest (reference land use system, only in Honduras)
SB and QSMAS were managed applying local practices to produce maize
(Z. mays) and common bean (P. vulgaris), with and without addition of
fertilizers. Fertilized treatments include 49 kg N + 55 kg P ha-1 at 8-10
days after planting (DAP) and 52 kg N ha-1 at ~30 DAP for maize; and 46
kg N + 51 kg P ha-1 at 8-10 DAP for common bean.
Here we present the research highlights that support the
recommendation of QSMAS as a validated eco-efficient option to
achieve multiple social, agricultural and environmental benefits in
rainfed systems of the sub-humid tropics in the face of climate change.
The knowledge generated in Honduras (Central America) by a CPWF
funded Project indicated that the Quesungual Slash and Mulch
Agroforestry System (QSMAS) can be a model production system for
implementing conservation agriculture principles to achieve sustainable food security and other
ecosystem services in drought-prone areas of hillsides in the sub-humid tropics in the face of land
degradation and climate change. As a suitable option to replace the slash and burn agriculture, QSMAS
can improve smallholder livelihoods through eco-efficient use and conservation of natural resources.
Participatory validation activities in Nicaragua and Colombia suggest that the principles embedded in
QSMAS can be readily accepted by resource-poor farmers and local authorities in similar agroecosystems.
Consortium for the Integrated Management of
Soils in Central America
(1) Establishment of a slash and burn
plot: cutting of forests and burning
of the resulting biomass
Nicaragua
and
Colombia:
Validation sites
Honduras:
Reference site
(3) Study sites
for QSMAS
(2) QSMAS plot for the
production of maize
Extrapolation Domain Analysis (EDA) for
QSMAS: bivariate map showing potential
areas for implementation of QSMAS across
the Pan tropical world.
*EDA performed combining Bayesian
(Bonham Carter et al. 1989; Bonham Carter
2002) and frequentist statistical models
(Jones et al. 2005).
Experience over three years of on-farm
participatory validation in Nicaragua
(Somotillo) and Colombia (Suárez) suggests
that QSMAS (or its principles) will be readily
accepted and adopted by smallholders in
similar agroecosystems (sub-humid tropics).
Farmer-to-farmer proved to be a useful
mechanism for QSMAS’ promotion and
dissemination.
Nicaragua (2005-06): QSMAS improved
net income (83%) compared to SB system.
Slash and Burn QSMAS
Gra
in y
ield
(t
ha-1
)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43
Slash and Burn QSMAS
Gra
in y
ield
(t
ha-1
)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43
Slash and Burn QSMAS
Gra
in y
ield
(t
ha-1
)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43
Slash and Burn QSMAS
Gra
in y
ield
(t
ha-1
)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43
Maize
Common beanDMS0.05= ns
DMS0.05= 0.43LSD
LSD
In synthesis:
• Soil-plant-atmosphere continuum: Reduced runoff, erosion, water turbidity and
surface evaporation; and increased infiltration, soil water storage capacity and use of
green water.
• Soil quality: Improved aggregation, structure, biological activity, organic matter,
fertility and fertilizer use efficiency.
• Green house gases (GHG): Reduced global warming potential and improved C capture.
• Food security: Improved crop water productivity and yields at lower inputs of labor.
Estimated value of
environmental services
(Honduras, 2007):
considering: (i) Soil and water
(runoff, infiltration, water
holding capacity, and soil
losses) attributes; and (ii) C
capture (soil organic carbon)
US$ 2,240 per hectare
Productivity: QSMAS improves
crop water productivity
compared to SB.
Cro
p w
ate
r p
rod
uc
tiv
ity
(k
g m
-3)
0 .0
0 .1
0 .2
0 .3
0 .4
0 .5
0 .6
Slash &
Burn
QSMAS <2
QSMAS 5-7
QSMAS >10
Bean
Maize
LSD 0.05 = 0.14
LSD0.05 = 0.10
Cro
p w
ate
r p
rod
uc
tiv
ity
(k
g m
-3)
0 .0
0 .1
0 .2
0 .3
0 .4
0 .5
0 .6
Slash &
Burn
QSMAS <2
QSMAS 5-7
QSMAS >10
Bean
Maize
LSD 0.05 = 0.14
LSD0.05 = 0.10
Ava
ilab
le w
ate
r co
nte
nt
(m3
m-3
)
0 .00
0 .08
0 .10
0 .12
0 .14
LS D0 .05
= 0 .015
Soil water: QSMAS improves dry season adaptation of crops through
higher soil water availability together with reduced runoff and
increased infiltration compared to SB.
-40
-30
-20
-10
0
1 0
2 0
3 0
4 0
DMS 0.05 = 6.2
DMS 0.05 = 6.6
Runoff
(mm
h-1
)In
filtra
tion
(mm
h-1
)
S lash and B u rn
Q S M A S
S econda ry F o rest
-40
-30
-20
-10
0
1 0
2 0
3 0
4 0
DMS 0.05 = 6.2
DMS 0.05 = 6.6
Runoff
(mm
h-1
)In
filtra
tion
(mm
h-1
)
-40
-30
-20
-10
0
1 0
2 0
3 0
4 0
DMS 0.05 = 6.2DMS 0.05 = 6.2
DMS 0.05 = 6.6DMS 0.05 = 6.6
Runoff
(mm
h-1
)In
filtra
tion
(mm
h-1
)
S lash and B u rn
Q S M A S
S econda ry F o rest
LSD
LSD
So
il l
os
s (
t h
a-1
)
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
2007 – LSD= ns
2006 – LSD= 1.08
2005 – LSD= 6.59
QSMASSecondary
Forest
Slash
and Burn
So
il l
os
s (
t h
a-1
)
0
1 0
2 0
3 0
4 0
5 0
6 0
7 0
8 0
2007 – LSD= ns
2006 – LSD= 1.08
2005 – LSD= 6.59
2007 – LSD= ns
2006 – LSD= 1.08
2005 – LSD= 6.59
QSMASSecondary
Forest
Slash
and Burn
Erosion: QSMAS protects soil by markedly
reducing soil losses (~7.5 times in two
years) compared to SB system.
Ch
an
ge
in
nu
trie
nt
sta
tus
(m
g k
g-1
)
-40
0
4 0
8 0
1 2 0
1 6 0
2 0 0
2 4 0
2 8 0
3 2 0
QSMAS Secondary
Forest
Slash
and Burn
T ota l N
A va ilab le P
Ch
an
ge
in
nu
trie
nt
sta
tus
(m
g k
g-1
)
-40
0
4 0
8 0
1 2 0
1 6 0
2 0 0
2 4 0
2 8 0
3 2 0
QSMAS Secondary
Forest
Slash
and Burn
T ota l N
A va ilab le P
Ch
an
ge
in
SO
M (
%)
-0 .9
-0 .8
-0 .7
-0 .6
-0 .5
-0 .4
-0 .3
-0 .2
-0 .1
0 .0
0 .1
0 .2
0 .3
0 .4
0 .5
S lash and B u rn
Q S M A S
S econda ry F o rest
QSMAS Secondary
Forest
Slash
and Burn
Ch
an
ge
in
SO
M (
%)
-0 .9
-0 .8
-0 .7
-0 .6
-0 .5
-0 .4
-0 .3
-0 .2
-0 .1
0 .0
0 .1
0 .2
0 .3
0 .4
0 .5
S lash and B u rn
Q S M A S
S econda ry F o rest
QSMAS Secondary
Forest
Slash
and Burn
Soil quality: QSMAS improves soil nutrient status and soil organic
matter (SOM) content (0-20 cm soil depth) compared to SB system
(after one year).
= SED
= SED
GHG emission: QSMAS reduces the risk (42%) for
global warming potential (GWP) compared to
slash and burn (SB) system (20 year scenario).
GW
P (
kg
CO
2 e
qu
iva
len
ts h
a-1
y-1
)
0
1 0 0 0 0
2 0 0 0 0
3 0 0 0 0
4 0 0 0 0
5 0 0 0 0
S lash and B u rn
Q S M A S
S econda ry F o rest
GW
P (
kg
CO
2 e
qu
iva
len
ts h
a-1
y-1
)
0
1 0 0 0 0
2 0 0 0 0
3 0 0 0 0
4 0 0 0 0
5 0 0 0 0
S lash and B u rn
Q S M A S
S econda ry F o rest
0 .0
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
0 .0
0 .5
1 .0
1 .5
2 .0
2 .5
3 .0
Cro
p y
ield
(t h
a-1)
-F LSD0 .05
= N S
2005
2006
2007
Average
LSD0 .05
= N S+ F
0 .0
0 .2
0 .4
0 .6
0 .8
1 .0
1 .2
LSD0 .05
= 0 .22
Cro
p y
ield
s (
t h
a-1)
0 .0
0 .2
0 .4
0 .6
0 .8
1 .0
1 .2
-F LSD0 .05
= N S
2005
2006
2007
Average
+ F
Honduras (2005-07): Average productivity of QSMAS is similar of
higher than in SB system (+F and -F = fertilizer and no
fertilizer, respectively).
Research for development activities support the recommendation of
QSMAS (or the application of its principles) as an option to achieve a
number of social, agricultural and environmental benefits in rainfed
systems of the sub-humid tropics.
Policy implications for achieving wider impacts include enabling:
•Regional–national-local goals to protect the sustainability of
agroecosystems while enhancing their functionality.
•Local agricultural and developmental extension systems.
•Incentives to communities to adopt more sustainable and
environmentally friendly production practices.
•Financial mechanisms to facilitate adoption of proposed changes.
•Physical infrastructure to sustain productivity gains.
•Benefit sharing mechanisms such as the payment for environmental
services (PES).
ACKNOWLEDGEMENTS: This project was partially funded by the Challenge Program on Water and Food of CGIAR. It was co-executed by the Integrated Management of Soil consortium (MIS) in Central America including INTA and UNA, Nicaragua; ESNACIFOR, UNA and FAO, Honduras; and CIAT - Honduras, Nicaragua and Colombia; Inter-institutional consortium for sustainable agriculture in hillsides (CIPASLA), Colombia; and National University of Colombia - Palmira. We thank E. Humphreys, M. Fisher, M. Rajasekharan, N. Asakawa, C. Benavides, G. Borrero, J.G. Cobo, L.F. Chávez, J. Galvis, M. del P. Hurtado, M. Quintero, J. Quintero, J. Ricaurte, V. Soto, M.T. Trejo, R. Vivas, A. Álvarez, O. Ayala, E. Melo and D. Vásquez for their contributions to this work.
Potential on the PES provided by QSMAS could enhance its acceptance in
countries with national objectives of protecting ecosystems in the face
of climate change. They may compensate:
•Reduced global warming potential (improved C capture and mitigation
of greenhouse gas fluxes)
•Increase of water quality and availability
•Conservation of biodiversity
•Increase of soil quality and resilience
•Recuperation of degrading soils
•Mitigation of impact related to natural disasters and/or climate change
QSMAS is an integrated land use management strategy embracing
principles of conservation agriculture that contribute to its
superior performance in terms of productivity, sustainability and
resilience.
QSMAS management practices leads towards efficient nutrient
cycling, improved crop water productivity, and increased and
sustained C assimilation and accumulation in a resilient production
system, thereby enhancing support for livelihoods in rural areas.
Under experimental conditions, QSMAS is equally effective as SB
system for the production of maize and more efficient to produce
common bean. The more dramatic effect is the increased
productivity of water in the later part of the bimodal rainy season,
when rainfall is usually irregular (dry spells on key stages of crop
development) or inadequate (shorter rainy season).
High natural variation in QSMAS plots (i.e. predominant vegetation,
soil properties) and marked differences on their management (e.g.
crop residues) demonstrates that the implementation of its
principles strongly relies on criteria of individual farmers that are
influenced by current and future needs of the householders.
Driving forces behind QSMAS adoption are multiple and articulated.
The success of the system in Honduras and Nicaragua is a reflection
of a community-based learning process in which local people and
extension service providers share ideas and learn together.
QSMAS benefits should be increased through intensification and
diversification with high value components (livestock and fruit crop
options).
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QSMAS plot bordered by forests
regenerated as result of
elimination of slash and burn
QSMAS plot: soybean (Glycine max
L.) production managed by women
Landscape in the region of Honduras
where QSMAS is practiced
Nicaraguan farmers being trained
by Honduran farmers on the
establishment of QSMAS plots