Adapting to change in banana-based farming systems of northwest Tanzania: the potential role of herbaceous legumes

The main objective of the study was to assess the potential contribution of various fodder and non-fodder legume cover crops to the management of N and improvement on soil productivity in smallholder farms in northwest Tanzania. The specific objectives, which together allow us to answer the main objective were:

1. i)  to evaluate the type and extent of changes in land use, cropping patterns and cattle keeping for the period 1961-1999 and the causal factors of change;

2. ii)  to assess the impact of changes on soil fertility management practices by farmers and the sustainability of the farming system in terms of nutrient balances;

3. iii)  to assess the adaptability and N2-fixation by forage and non-forage herbaceous legumes under on-station and on-farm conditions;

4. iv)  to understand factors that may hinder the adoption of legumes by farmers and identify the types of herbaceous legume species that are most desired by farmers;

5. v)  to understand the nitrogen release behaviour of farmer selected herbaceous legumes and the effect of application of their residues on maize yield under on-station and on-farm conditions;

6. vi)  to determine the N fertiliser equivalency of the above ground parts of legume cover crops and the efficiency of use of legume residue N by the subsequent maize crop;

7. vii)  to determine the best way to manage legume cover crops and their residues and the associated labour cost and labour productivity under farmer conditions;

8. viii)  to identify opportunities for soil fertility improvement through use of legumes cover crops by farm household with different resource endowment through higher production of maize and manure and

9. ix)  to assess the trade-offs among the economic goals (crop and manure production) and a sustainability goal (N-balance) of alternative crop activities in the annual cropping fields...