Post-fire soil erosion mitigation at the scale of swales using forest logging residues at a reduced application rate
Prats, Sergio A. ; González-Pelayo, Óscar ; Silva, Flavio C. ; Bokhorst, Koen J. ; Baartman, Jantiene E.M. ; Keizer, Jan J. - \ 2019
Earth Surface Processes and Landforms (2019). - ISSN 0197-9337
effectiveness - erosion - mulch - organic matter - wildfire
Mulching with forest residues has proved to be highly effective in reducing post-fire soil losses at the plot scale. However, its effectiveness has not been quantified at the application rates that are typically used in operational post-fire land management (2–3 Mg ha-1 using straw), as well as at scales larger than 100 m2. The present study compared post-fire erosion rates for six convergent hillslopes or swales of 500 to 800 m2, three of which were left untreated while the other three were mulched immediately after the fire with shredded eucalypt bark at a rate of 2.4 Mg ha-1. Erosion rates were monitored at irregular intervals during the first three post-fire years, whilst ground cover was assessed yearly. Selected topsoil properties (0–2 cm) such as organic matter content and aggregate stability were determined at a single occasion – two years after the wildfire, for three micro-environments separately: bare soil, and under mulch/litter and vegetation. Soil losses on the untreated swales decreased with post-fire year from 2.2 to 0.4 and 0.11 Mg ha-1 yr-1 (respectively for the first, second and third post-fire years), while the mulched swales produced 84%, 77% and 38% less soil losses than the untreated swales. Soil losses also depended on slope aspect, with the north-facing swales producing less erosion than the west-facing ones. This could be linked to their significant differences in bare soil, vegetation and stone cover, or a combination thereof. The type of micro-environment also played a significant role in topsoil properties (stone content, bulk density, resistance to penetration/shear stress, porosity and organic matter content). The present results add to the increasing evidence that forest residues should be duly considered for operational post-fire land management. Forest residues were highly effective in reducing erosion from swales at application rates as low as the typical 2 Mg ha-1 of post-fire straw mulch.
Understanding the Sustainability of Private Development Initiatives : What Kind of Difference Do They Make?
Kinsbergen, Sara ; Schulpen, Lau ; Ruben, Ruerd - \ 2017
Forum for Development Studies 44 (2017)2. - ISSN 0803-9410 - p. 223 - 248.
citizen initiatives - civil society - development aid - effectiveness - sustainability
In the Netherlands, there is a large group of small-scale, voluntary development organisations, referred to as Private Development Initiatives (PDIs). By classifying PDI interventions based on their potential sustainability, we aim to enhance our understanding of PDIs as alternative development actors and to get insight into the diversity within this group. We rely on detailed data of 49 Dutch PDIs active in Kenya and Indonesia. The classification is based on a combined analysis of both the intervention type (‘what’ they do) and the intervention manner (‘how’ they work) of PDI activities. This results in a typology that outlines the potential sustainability of PDI intervention strategies. We find that diversity regarding the potential sustainability of PDI interventions is large. Whereas several organisational characteristics influence the choice of the intervention strategy (e.g. independence local partner, budget), intrinsic drivers such as motivation and the personal or professional background of PDI members tend to be of great influence for the potential sustainability of the intervention strategies adopted by the PDIs.