Farmer's decisions and landscape change : an actor-based approach for land-use research
toon extra info.
|[S.l. : s.n.]|
|126 p fig., tab|
|Proefschrift Wageningen toon alle annotatie(s)
Met lit. opg. - Met samenvatting in het Engels en Nederlands
|Bregt, Prof. dr. ir. A.K. ; Veldkamp, Prof. dr. ir. A. ; Verburg, Prof. dr. ir. P.H.|
|Samenvatting door auteur||
This study aimed at understanding the effects of crop management practices on soil macrofauna and the links with soil aggregation and soil organic matter dynamics, which is key to the improvement of infertile or degrading soils in Sub-Saharan Africa. Soil macrofauna, especially earthworms and termites, are important components of the soil ecosystem and, as ecosystem engineers, they influence the formation and maintenance of soil structure and regulate soil processes, such as organic matter decomposition and nutrient dynamics.
In comparison with natural systems, earthworm and termite diversity and abundance were low in fallow, high soil-carbon (C) and low soil-C arable treatments in 12 long-term trial fields across the sub-humid to semi-arid tropical zones in Eastern and Western Africa. Continuous crop production had significant negative effects on earthworm diversity, but little effect on termite diversity, as compared to long-term fallow. Agricultural management resulting in high soil C increased earthworm and termite diversity as compared to low-C soil. Long-term application of manure in combination with fertilizer resulted in higher earthworm diversity and biomass, associated with improved soil aggregation and enhanced C and N stabilization within this more stable soil structure. These practices therefore result in the dual benefits of improving soil physical and chemical properties.
A micromorphological study of undisturbed soil thin sections showed that fallowing, conservation tillage plus residue application (in East Africa) and hand-hoeing plus manure (in West Africa) enhanced biogenic soil structure formation, resulting in a well developed soil structure and a continuous pore system characterized by many faunal channels. In contrast, intensive tillage and absence of organic inputs resulted in soil with less biogenic soil structural features.
Farmers in Nyabeda, West-Kenya, were aware of the activities and nesting habits of termites, but 90% of the farmers perceived termites as pests.
This study has shown that the soil macrofauna, especially earthworms, and to a lesser extent termites, are important drivers of stable aggregation in Sub-Saharan agroecosystems, with beneficial effects on soil physical and chemical properties. However, their beneficial impact on soil aggregation is reduced with increasing management intensity and associated soil disturbance due to cultivation. This knowledge is important in designing agricultural management systems aimed at increasing long-term soil fertility in Sub-Saharan Africa.
|Trefwoorden (cab)||landgebruik / boeren / houding van boeren / besluitvorming / landschap / plattelandsplanning / toestandsverandering / structurele verandering / dynamiek van het ruimtegebruik / landschapsplanning|
|Landgebruiksplanning / Agrarische bedrijfsvoering|
|Toelichting||In dit proefschrift wordt een actorgerichte benadering beschreven die landgebruiksveranderingen probeert te verklaren en simuleren als een reactie van boeren op socio-economische en biofysische veranderingsprocessen. Deze aanpak werd geïmplementeerd in een ‘agent-based’ raamwerk dat verschillende concepten en hulpmiddelen combineert: de bereidheid en capaciteit van boeren, besluitvormingscorridors, typologieën van ‘agents’ en beslissingsmechanismen gebaseerd op kansberekening. De beschrijving en implementatie van dit modelleerraamwerk heeft verschillende bijdragen gehad aan het onderzoek naar landgebruik|
|Toelichting (Engels)||This dissertation has two objectives. The first objective is to link conceptually individual decisions and land-use/cover change (LUCC) patterns in rural regions. The second objective is to use these concepts to explore the influence of policy on LUCC as a response of farmers' decisions. To achieve these objectives, different approaches are used. Firstly, agent typologies are used to simplify and allocate the regional diversity of farmers' decisions. Secondly, an agent-based approach is used to link individual decisions and LUCC patterns in a regional model. Thirdly, this approach is applied to explore how farmers' response to national and global socio-economic and biophysical processes can affect the landscape of a Dutch rural region. Fourthly, this approach is applied to explore how farmers' participation in voluntary mechanisms to restore native vegetation can affect the landscape in rural Australia. Finally, the implication of these results for LUCC research and policy-making are discussed.|