Assessing the potential of biochar and charcoal to improve soil hydraulic properties in the humid Ethiopian Highlands: The Anjeni watershed
Bayabil, H.K. ; Stoof, C.R. ; Lehmann, J.C. ; Yitaferu, B. ; Steenhuis, T.S. - \ 2015
Geoderma 243-244 (2015). - ISSN 0016-7061 - p. 115 - 123.
central rift-valley - organic-matter - physical-properties - land management - nile basin - agronomic performance - chemical-properties - climate-change - maize yield - retention
Biochar has shown promise for restoring soil hydraulic properties. However, biochar production could be expensive in the developing world, while charcoal iswidely available and cheap. The objective of this study is therefore to investigate whether some of the charcoal made in developing countries can also be beneficial for improving soil hydraulic properties, and explore whether charcoal could potentially restore the degraded African soils. Laboratory and field experiments were conducted in the Anjeni watershed in the Ethiopian highlands, to measure soil physical properties including soil moisture retention and infiltration rates. Soils were dominantly clayey with pH in the acidic range, low organic carbon content, and steady infiltration rates ranging between 2 and 36 mm/h. Incorporation of woody feedstock (Acacia, Croton, and Eucalyptus) charcoals significantly decreased moisture retention at lower tensions (10 and 30 kPa), resulting in an increase in relative hydraulic conductivity coefficients at these tensions. While wood (oak) biochar decreased moisture retention at low tensions, corn biochar increased retention, but effects were only slight and not significant. Surprisingly, available water content was not significantly affected by any of the amendments. Overall findings suggest that wood charcoal amendments can improve soil hydraulic properties of degraded soils, thereby potentially reducing runoff and erosion.
Transboundary water justice: a combined reading of literature on critical transboundary water interaction and "justice", for analysis and diplomacy
Zeitoun, M. ; Warner, J.F. ; Mirumachi, N. ; Matthews, N. ; McLaughlin, K. - \ 2014
Water Policy 16 (2014)S2. - ISSN 1366-7017 - p. 174 - 193.
global environmental justice - hydro-hegemony - south-africa - nile basin - power - management - allocation - equity - law - hydrosolidarity
By reviewing and blending two main bodies of research (critical transboundary water interaction analysis and centuries of thought on social justice) this paper seeks to improve international transboundary water interaction analysis and diplomacy. Various implications for transboundary analysis and diplomacy are grouped under themes of equitability, process/outcomes, and structural concerns. These include shortcomings of analysis and policy based on unfounded assumptions of equality, and options excluded from consideration by the legitimisation of particular concepts of justice over others. As power asymmetry is seen to enable or disable justice claims and conflict resolution efforts, the importance of ensuring equitable outcomes as a pre-condition for cooperation is asserted. Similarly, water conflict resolution is found to be more fair – procedurally – than is conflict management, and may be supported to a limited extent by international water law. A number of analytical tasks are suggested for future research and policy, including a call to scrutinise the source of legitimacy of strands of justice invoked. Given the very many perspectives on justice that exist in the network of relevant actors, potential bias in research and diplomacy could be reduced if all involved openly stated the morals underpinning their understanding of ‘justice’.