| Abstract: |
| Soil erosion firom. traditional open-field methods of farming threatens the sustainability of maize production in the Philippine uplands, on which a large and growing population depends. Intercropping maize between hedgerows of shrub legumes has emerged as the focus of soil conservation research and extension in the uplands, because of a potential to sustain production by reducing soil loss and contributing nitrogen to the cropping alleys. Hedgerow intercropping with shrub legumes has been considered an appropriate soil conservation technology for upland fanning systems, because of its low input requirements relative to structural soil conservation technologies such as bench terraces.
Although considerable resources have been committed to the research and extension of hedgerow intercropping in the Philippine uplands, adoption by farmers has proven to be transient, and rarely sustained once extension projects are completed. Persistent adoption has been limited to modified versions of hedgerow intercropping including natural vegetation and grass strips, which require less labour to establish and maintain than shrub legume hedgerows. Limited adoption has been attributed to socioeconomic factors, farmer characteristics and inappropriate and inflexible presentation of the technology to farmers.
In this thesis, bioeconomic analysis is used to investigate the economic incentives for upland farmers to adopt hedgerow intercropping relative to traditional open-field maize farming. Cost-benefit analysis is used to compare the economic returns from maize fanning with and without hedgerows. Two erosion/productivity models, APSrM and SCUAF, are used to simulate the long term effect of soil erosion on maize yields for the alternative farming methods. Economic data obtained through surveys of maize farmers in two upland communities, Timugan and Claveria, are used to derive production budgets for maize farming.
The results indicate that hedgerow intercropping has potential to sustain maize yields by controlling erosion and contributing nitrogen to the cropping alleys. In the long term, hedgerow intercropping may be an economically attractive method of sustaining cropping, particularly on erodible soils where productivity declines rapidly under open-field fanning. However, high discount rates, insecure land tenure and
share-tenancy reduce the value to farmers of sustained economic returns from hedgerow intercropping relative to the high cost of hedgerow establishment. Hence in the short term, traditional methods of open-field farming can provide high economic returns to farmers,* despite high rates of soil erosion.
Hedgerow intercropping with shrub legumes is the least attractive form of hedgerow intercropping to farmers, because of high establishment costs. Alternative forms of hedgerow intercropping, such as natural vegetation and grass strips, are more attractive to farmers because of reduced establishment and maintenance costs. Extension strategies that rigidly adhere to bedgerow intercropping with shrub legumes therefore need to be reappraised. |
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