Staff Publications

The northeastern mountains make up the major part of agricultural land in Tanzania. These areas have been experiencing rapid population growth, leading to increased demand for food, fuelwood and agricultural land. Most parts of the slopes have been experiencing declining soil fertility and severe soil erosion due to continuous cultivation and other factors. As a result, agricultural productivity has declined, leading to serious food shortages.

The aim of this study was to explain household adoption behaviour towards the use of improved soil conservation measures to reduce land degradation (soil erosion) and reverse declining soil productivity and attain agricultural susutainability in the northeastern mountains of Tanzania, with reference to the north Pare and the west Usambara mountains. In addition, this study was intended to outline implications and recommendations for policy and institutional support for soil conservation in the study area. The assumption is that adoption of soil conservation measures and the level of investment in soil conservation by households are the means for achieving sustainable production system in the northeastern mountains.

An interdisciplinary approach which incorporate both the sociological and the economic approaches for analysing households' decision behaviour are used in modelling household adoption of improved soil conservation measures. Our analytical framework is based on Ervin and Ervin's (1982) approach for analysing adoption of soil conservation practices. In our model three components of adoption decision process are linked: the perception of soil erosion problem, the decision to use improved soil conservation measures and the level of investment or effort devoted to soil conservation among adopters.

A study designed to address the objectives of the study was carried out in 1995/1996 in the west Usambara mountains and north Pare mountains. Three empirical models: perception of the soil erosion problem model, adoption of improved soil conservation model and conservation effort model were developed for the study. These models incorporate several socio-economic, institutional and physical factors as independent variables. The empirical analysis was carried out using binomial logit models to estimate the effects of the independent variables on the probability of the head of household to perceive the soil erosion problem and to adopt soil conservation measures. Poisson regression model was used to identify the determinants of effort (level of investment) the household is willing to devote into soil conservation.

The results from this study indicate that personal characteristics of the heads of households (gender/sex and marital status), participation in activities of soil and water conservation programmes (SWC) and the mountain area where the household is located are the determinants of perception of the soil erosion problem in the study area. Marital status and household location have negative influence on perception of the soil erosion problem. The results show that the probability of perception of the soil erosion problem is lower among single heads of households. Also, perception of the soil erosion problem is lower among households in the west Usambara mountains than households residing in the north Pare mountains. The participation in promotional activities of SWC programmes and sex of heads of households have a positive influence on perception of the soil erosion problem. The participation in promotional activities of SWC programmes increases the level of exposure to soil erosion problem, hence perception of the soil erosion problem. Also, the results indicate that the probability of perceiving soil erosion problem is higher for male-heads of households than female-heads of households.

The decision on whether or not to use improved soil conservation measures is determined by the economic rank of the household indicated by whether he has cash crop or not and farm size. In addition to economic rank, institutional support from SWC programmes and participating in labour sharing groups (kiwili/ vikwa) are among the most important incentives to using improved soil conservation measures in the study area. Ranking of soil erosion problem also play a major role in enhancing adoption of improved soil conservation technologies. The results also indicate that household's knowledge about soil erosion increases the likelihood of adoption of improved soil conservation measures. Furthermore, households with off-farm income are less likely to use improved soil conservation measures.

It is evident from this study that socio-economic and institutional factors influences the level of investment households commit to soil conservation. Institutional support from SWC programmes especially educational activities such as village-level training, village tours, information from mass media and participation in conservation planning enhance the level of investment in soil conservation significantly. The level of family labour, off-farm income earning and the way household rank soil erosion problem are also strong determinants of the level of resources devoted to soil conservation among adopters. Other determinants of level of effort among adopters are level of extension visits, household's education level, participating in labour sharing groups and off-farm income.

The study demonstrate that the decision to use improved soil conservation technologies and the level of investment in soil conservation (effort) are separate decisions. The two decisions however, share some identical explanatory variables and are both influenced by sociological, economic and institutional factors. Despite of these commonalities we observe that economic and institutional factors play more important role in determining the decision to use improved soil conservation while institutional factors are more important in determining the level of resources committed into soil conservation. We also observe that households' characteristics and institutional factors, especially promotional activities of SWC programmes and the level of exposure of household to conservation activities are key determinants of households' perception of the soil erosion problem.

From this study we came up with the following recommendations for policy and soil conservation institutional support for the study area:

1. There is need to for the government to strengthen, expand and support long-term soil conservation programmes in the area.
2. To encourage adoption of improved soil conservation technologies, policies and institutional support should be focused on enhancing willingness and ability of farm households to use improve soil conservation technologies.
3. In order to increase adoption of effective soil and water conservation measures in the study area, understanding why some households (non-adopters) fail to adopt improved conservation technologies is crucial.
4. Soil and water conservation programmes operating in the northeastern mountains should provide long-term support and incentives to adopters to ensure that adopters who do not perceive the soil erosion problem maintain the adopted conservation measures. This should go hand in hand with efforts to promote knowledge about soil erosion problem through training, mass media and other methods.