Innovative agricultural intensification to cope with demographic and climatic changes for subsistence producers : a case study of Sandfly Island, Solomon Islands

Abstract: This research aims to study the dynamics of agricultural intensification amongst the small island community of Sandfly Island, Solomon Islands, and to observe the spreading of new agricultural practices of intensification that can help mitigate the pressures of climate change on the one side; and on the other side of a growing food demand from a growing population. The intention is to describe the variety of agricultural practices and the variation of production parameters such as fallow length, length of cropping period, number of plots in agricultural rotation and size of plots as to assess the state of agricultural intensification and to find what are the environmental constraints to production. Conducted interviews also focus on the state of knowledge and awareness of producers about the pressures on land of climate change and population rise; then on producers’ knowledge of mulching and composting as innovations that can help mitigate the effects of these two pressures. Finally, producers’ reasons of adoption or non-adoption of these innovations are explored. This is done by the means of soil analysis and the interviewing of 62 producers across 8 different localities of Sandfly Island. What is found is that producers across the island share the same agricultural practices of no-external-input bush fallow, except for one producer who farms his land under the system of non-shifting multi-cropping with mulching as input. Some few other producers who have integrated mulching in their shifting agriculture. Nevertheless, producers from higher population density areas are shown to have shorter fallow lengths, to clear smaller gardens and to generally have less available land for production than producers from lower density population areas of the island. Producers who have less land available for agriculture also tend to have shorter fallow lengths; they occur in majority in high population density areas but not exclusively. Evidence was found of pressure on land both because of intensification and because of changing climatic conditions as producers complain of longer periods of drought broken by more violent episodes of rain and decreasing agricultural productivity. It was also found that roughly two thirds of producers know of composting and mulching though only 10% of them have adopted the innovations. Adoption rates vary from one source of knowledge to the other: school teaching and workshops led to adoption rates of 10 and 20 % respectively. Reasons of non-adoption vary significantly across groups of producers as big landowners and producers from the less populated areas state threefold more often that the adoption asks for too much work. Big landowners mention 97% and 25% more respectively a need for guidance and a need for further knowledge to adopt the innovations. The argument that adoption goes against the custom way is mentioned by 23% of the population and is not stated in significantly different proportions across clusters. The island’s soil analysis showed that there is great variability in fertility amongst soils of the island that can be traced to either a difference in topsoil accumulation and thus soil organic carbon amongst soils of similar origins, or because of different parent materials. These findings imply that, despite bush fallow being an appropriate and efficient method to restore soil fertility in the conditions of Sandfly Island, the heavy non-innovative intensification of agriculture in zones of high population density is no longer ensuring long-term sustainability of land use. Climate change aggravates this pressure. Such a situation offers great opportunity for appropriate agricultural innovations that can help mitigate the pressures; such as contouring to reduce soil erosion, mulching and composting as soil amendment. Some producers have made the decision to adopt such innovations, showing that the process of innovation diffusion is on the way on Sandfly Island, though at an early stage. Stated reasons of non-adoption show that small landowners and producers from higher populated areas perceive a higher relative advantage to adopt innovative agricultural practices as they are keener to accept the higher labour input it requires. In comparison, big landowners and producers from low population density areas still have the possibility of non-innovatively intensify their land use without increasing labour input. In consequence, there are reasons to believe that diffusion will happen more effectively amongst small landowners and producers of high population density areas. Further research could bring relevant insight on whether this proves to be true.