Facilitated learning in soil fertility management: assessing potentials of lowexternal-input technologies in East African farming systems
De Jager, A1., Onduru, D2., Walaga, C3.
1
Wageningen University and Research Center, Agricultural Economics
Research Institute (LEI), Den Haag, The Netherlands
2
ETC- East Africa, Nairobi, Kenya
3
Environmental Alert, Kampala, Uganda
ABTRACT
This paper describes the experiences and results of a study conducted in 4
districts of Kenya and Uganda during the period 1997-1999 in which
researchers and relevant stakeholders were involved in: (1) participative
diagnosis of soil fertility status and management practices, (2) identification,
testing and evaluation of low-external-input technologies, (3) formulation of
enabling policies and measures at district level. In all 4 research sites and
studied farm management systems, the future agricultural productivity is
threatened by soil nutrient depletion. The cause of depletion however, differs
considerably between the sites. Low and erratic economic returns to
agricultural production were observed with a considerable part of these returns
based on nutrient mining. Low-External Input technologies (LEIA) alone offer
limited opportunities to address the observed problems of soil nutrient
depletion in the region. Site-specific combinations of external inputs and
LEIA techniques appear to be the most appropriate strategy.
INTRODUCTION
Continued natural resource degradation, increasing levels of poverty,
unintended negative impacts of globalisation, low level adoption of
technologies, poor governance and marketing infrastructure, and increasing
population pressure have been observed to be great impediments to increasing
food production in sub-Saharan Africa (McCulloch et al., 1999; PinstrupAndersen, 2000). In recent years various publications have addressed the
magnitude of resource degradation (Stoorvogel et al., 1993; Van der Pol,
1993; Scherr, 1999; Smaling et al., 1999), and technical solutions to the
observed constraints have been proposed (Smaling and Braun, 1996;
Mokwunye et al, 1996; Braun et al., 1997). So far, impacts have been rather
limited since many of these technical options require relatively high capital
investments, need a well-functioning infrastructure and a conducive policy and
market environment, all of which are constraining factors in most parts of
SSA.
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In response to the low success rate, the research community and development
organisations are shifting their focus to developing Low External Input
Agriculture technologies (LEIA). However, the impacts of LEIA is still a
subject of debate with some authors highlighting success stories (Rey et al.,
1996; Reijntjes et al., 1992) while others are voicing their inadequacy to meet
increasing food demands (Reuler and Prins, 1993; Koning et al., 1998; Blaikie
et al., 1997). A new line of thought attempts to combine low and high input
technologies in an Integrated Nutrient Management (INM) approach which
attempts to maximise the use of local resources and optimise application of
external inputs (Smaling et al., 1996; Pretty, 1995).
In the search for INM-practices, LEIA and organic farming practices have
hardly been examined systematically. Furthermore, methodologies of study
have been anecdotal in nature and lacking active participation of farm
households, relevant agricultural players and policy makers who have to
satisfy multiple goals. This paper describes the experiences and results of a
project in four districts in Kenya and Uganda during the period 1997-1999 in
which farmers, extensionists, NGOs, researchers and district policy makers
joined hands through a learning process to:
 Diagnose constraints to soil fertility management and opportunities for
improving the same;
 Identify, test and evaluate low-external-input technologies; and to
 Formulate enabling policies for soil fertility management with district
policy stakeholders.
METHODOLOGY
The study was conducted in four research sites in Kenya and Uganda, two
with a high agricultural potential (fertile soils, high and reliable rainfall) and
two with a medium to low agricultural potential (low soil fertility, low and
unreliable rainfall). LEIA and Conventional farm management, with 14-18
households each, were studied in each site. LEIA management’ was defined as
farm households trained in Low-External Input technologies (composting,
application of liquid manure etc.) and have applied at least three of those
techniques on more than 50% of the cultivated area over a minimum of 3
consecutive years. Conventional management’ was defined as farm
households representative of the farming system in the study site, have
comparable production resources to that of LEIA group, but not practising any
of the defined LEIA techniques.
The nutrient monitoring approach (NUTMON) was used (De Jager et al.,
1998, 1999). The approach distinguishes a diagnostic phase and an iterative
and participative technology and policy development phase. The diagnosis
consisted of the following activities: (1) farm households’ assessment of
natural resources using soil maps, transect walks and nutrient flow maps, (2)
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soil sampling and analysis according farmers soil maps, (3) monthly
monitoring using NUTMON questionnaire and (4) analysis. Analysis of the
data consisted of (1) analysis of the largely qualitative, farmers’ assessment of
natural resource management, (2) analysis of the quantitative nutrient flows
using the NUTMON methodology and soil sample results and (3) integration
of the two previous steps and discussing results with participating farmers.
Impact assessment of selected LEIA techniques was done through a
Participatory Technology Development (PTD) process (Reijntjes et al., 1992)
in which technologies were jointly selected, experiments designed, monitored,
data collected and evaluated, and results shared with farmers using
participatory tools. Based upon the participative diagnosis, the results of the
PTD, an inventory of historic developments in the district, and an inventory of
the existing and relevant policies in the research sites, draft scenarios for
future developments in the research sites were formulated. They were
discussed in District policy stakeholders workshops where they were finalised
and a prioritised action plan drawn by the policy makers attending the
workshop.
RESULTS
Soil and nutrient flow maps enabled farmers to visualise nutrient flows and
provided insight into soil nutrient status (Figure 1). The application of the
NUTMON model showed that there were marginal differences in nutrient
balances between the conventional and LEIA farm management systems
(Table 1).
Table 1
Nutrient stocks and flows in 4 districts in Kenya and Uganda in
the period 1997-1998
N-stock (kg/ha)
N-flow (kg ha-1,yr-1)
N-flow (‰ of stock,yr-1)
P-stock (kg/ha)
P-flow (kg ha-1,yr-1)
P-flow (‰ of stock,yr-1)
K-stock (kg/ha)
K-flow (kg ha-1,yr-1)
K-flow (‰ of stock,yr-1)
Machakos
(LPA)
CONV LEIA
3900
6400
-21
-25
-5
-4
2000
1700
2
1
1
1
7800
10200
-9
2
-1
0
Nyeri
(HPA)
CONV
LEIA
12200
12300
-99
-91
-8
-7
7900
8000
-23
-27
-3
-3
10400
15300
-23
18
-2
1
Pallisa
(LPA)
CONV
LEIA
3100
3000
-3
-4
-1
-1
1000
2500
0
0
0
0
6100
6300
2
1
0
0
Kabarole
(HPA)
CONV LEIA
6800
8300
-126
-95
-18
-11
10300
9000
-70
-57
-7
-6
7800
8400
-55
-7
-7
-1
LPA – Low-Medium Potential Area
HPA – High Potential Area
CONV - Conventional farm management practices
LEIA – Low-external-input farm management practices
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The differences between the districts were much more profound. The high
potential areas, although different in farming system, both showed a relatively
high N, P, K nutrient content of the soil, but also more negative nutrient
balances at farm level, especially for N (90–125 kg ha-1 year-1 representing an
annual 7-18 ‰ loss of the stock). The latter was mainly due to high erosion,
leaching and gaseous losses, despite relative high uses of mineral and organic
fertilisers (Figure 1). In Machakos district (Kenya), intensive crop farming on
relatively poor soils results in negative nutrient balances and an annual decline
in N-stock of 5 ‰ at farm level, mainly due to very low levels of external
Figure 1 Average farm nitrogen flows per type, research site and
management type
200
150
100
Human excreta
Erosion
50
Gaseous los.
Leaching
0
Manure
kg/ha
Crop residues
N in crop/livestock products
-50
Biological fixation
Atmospheric dep.
-100
Grazing
Organic fertilizer
Mineral fertilizer
-150
-200
-250
Machakosconv
MachakosLEIA
Nyeri-conv
Nyeri-LEIA
Pallisa-conv
Pallisa-LEIA
Kabaroleconv
KabaroleLEIA
inputs applied. In the low potential areas of Pallisa district (Uganda), keeping
of livestock under free-range systems results in nutrients from communal
grazing lands being transported into cropping land
The economic performance indicators showed no clear differences between
the management systems. However, analysis of labour data showed that LEIA
management requires more total farm labour than conventional management.
The farms in high potential areas realised on average higher net farm income
levels both per farm and per unit area. In Kenya off-farm income is of crucial
importance to the total family income, reducing the differences in financial
resources between the two areas. When valuing the depleted nutrients against
replacement costs, it was observed that huge differences between the districts
occur. In Pallisa the replacement cost accounted for 5% of the net farm income
while the figure for Nyeri was 11%. In Machakos and Kabarole a considerable
proportion of the net farm income was based upon nutrient mining with
respective figures of 25-30% and 60-70%. The economic efficiency of crop
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activities, expressed in gross margins per acre, tended to be slightly higher for
the LEIA farm management systems (although not statistically significant).
The technology identification and experimental design exercise resulted in a
research plan for on-farm testing in each research district. The results show
that significant increases in yield and economic returns can be realised with
relative high application levels of compost, but that availability of material and
labour inputs soon become limiting factors (Table 2).
Table 2
Nyeri (HPA,
Kenya)
Summarised results from tested low-external input technologies




Machakos (LPA,
Kenya)





Kabarole (HPA,
Uganda)


Pallisa (LPA,
Uganda)


In conventional farms the existing practice of manure and DAP application
can be replaced by an application of compost alone without any significant
impact on yield and economic returns.
On farms with LEIA management the addition of liquid manure had no
significant impact on yields and economic returns.
Residual impacts of the treatments in the following season were limited.
From the economic point of view an application of 8-9 ton of
manure/compost per acre is preferred above 17 ton/acre.
In both management systems a high application of compost with an
additional application of liquid manure gave a significant higher yield and is
attractive in economic terms.
In both management systems a 50% reduction of the high level compost
application level showed similar treatment effects at 50% reduced yield
levels compared to the high dose treatments.
On conventional farms the treatment with reduced dose of compost was
economically less attractive, while on LEIA farms a slightly higher gross
margin was realised but lower returns to labour.
When the economic impact is expressed in returns per labour day however,
the addition of liquid manure was less attractive in both farming systems.
On farms with conventional management only a very slight residual effect
could be observed in maize yield in the following season, while on LEIA
farms a strong residual impact was observed.
A high level of manure application had a positive impact on the yield of
crops in at least two consecutive cropping seasons.
Although manure had a considerable impact on yields, the economic
returns in two seasons were lower than farmers’ practice when manure is
valued at Ush 14000 per ton.
Application of compost, deep tillage and mulch are low-external-input
options, which can improve yields in food crops.
Although the selected low-external-input technologies had a considerable
impact on yields, the economic impact (over a 2-season period) at farm
level is absent or very limited.
LPA – Low-Medium Potential Area
HPA – High Potential Area
Policy discussion workshops were held in each district with district policy
makers from various ministries, researchers, extension staff, NGO-staff, staff
from development projects and others. In Table 3 the formulated development
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scenarios, the conditions required for implementation and a prioritised action
plan are presented for Nyeri district as an example.
CONCLUSIONS
In all four research sites and all studied soil nutrient management systems the
future agricultural productivity is seriously threatened by soil nutrient
depletion. The cause of depletion however differs considerably between the
sites. The nutrient status was considerably higher in the high potential areas
compared to the low potential areas Soil nutrient analysis revealed that no
differences in soil nutrient status could be observed between LEIA and
conventional management.
In general rather low and erratic economic returns to agricultural production
activities were observed, and moreover a considerable part of these returns are
based upon nutrient mining. LEIA farm management resulted in comparable
net farm income levels as conventional farm management. In the low potential
areas slightly higher income levels were realised with LEIA management. Offfarm income is an increasingly important factor in family income, especially
in Kenya. Therefore a targeted exploration of value-added production
alternatives (agriculture and non-agriculture) is required to sustain the
livelihood in rural areas. Research and development initiatives addressing soil
fertility depletion in East Africa should widen its focus beyond the agricultural
sector.
Table 3
1
2
3
4
5
6
7
8
9
10
Summarised results from district stakeholders workshop in
Nyeri
Establishing efficient and relevant information flows to farmers in a wide variety of
technical issues concerning increased sustainable production methods in crops and
livestock (much knowledge on the shelve currently not applied)
Increase availability of credits and making subsidies available for sustainable production
techniques
Establishing organised market structures for inputs and outputs
Better targeted and timely implemented government policy to facilitate agricultural
production such as land and price policies
Efficient and large-scale implementation of on-farm integrated nutrient management
research
Facilitation of (rural) agro-industry development
Efficient soil analysis available to farmers at affordable prices
General community empowerment through training, information, group formation etc.
Further facilitation of soil and water conservation measures, including water harvesting
General improvement of infrastructure (roads, communications etc.)
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Low-external input technologies alone offer limited opportunities to address
the observed problems of soil nutrient depletion in the region. Significant
increases in yield and economic returns could be realised with relative high
application levels of compost, but availability of material and labour inputs
then become limiting factors. Appropriate combinations of external inputs and
LEIA techniques appear the most appropriate alternative strategy.
Changes in agricultural policies are required to provide sufficient incentives
for farmers to undertake short- and long-term investment in soil fertility and
soil nutrients. Experiences from this study have shown that policy makers
need to be involved, at an early stage, in monitoring research activities geared
towards soil nutrient improvement.
ACKNOWLEDGEMENTS
The European Union and the Dutch Ministry of Agriculture, Nature
Management and Fisheries are gratefully acknowledged for supporting this
research.
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Corresponding Author Contact Information:
A. de Jager, Wageningen University and Research Center, Agricultural
Economics Research Institute (LEI), P.O. Box 29703, 2502LS Den Haag, The
Netherlands, Phone + 31 70 3358341; Fax + 31 70 3615624;
a.dejager@lei.wag-ur.nl, ORAL, Engaging diverse stakeholders in support of
small farms
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