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A holistic evaluation of conservation agriculture as a measure to combat desertification and land degradation in the North Ethiopian Highlands

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Conservation agriculture (CA) is often quoted as a beneficial resource-saving technique for dryland agriculture, albeit its large-scale implementation is mainly hindered by farmer’s acceptance problems. This holistic study combines soil-water modelling and emi-quantitative interviewing to evaluate the practice of conservation agriculture in the May Zeg-zeg catchment (MZZ; 187 ha) in the North Ethiopian Highlands as a soil management technique, and to evaluate the social factors that influence the acceptance of conservation agriculture by farmers in the catchment. The study of such practice is important especially under conditions of climate change, since EdGCM (Educational Global Climate Model) simulation predicts an increase in precipitation by more than 100 mm yr-1 in the study area by 2040. Firstly, on several farmlands, CA was checked against plain tillage (PT) for values of field-saturated infiltration rates, soil organic carbon, runoff and soil loss. Results show no significant differences for infiltration rates but significant differences for runoff and soil loss (as measured in the period 2005–2011). The collected information was used to predict future catchment hydrological response for catchmentwide implementation of CA under the predicted wetter climate, by calculating Curve Numbers for farmlands with CA, by calibrating the Revised Universal Soil Loss Equation’s management factor P for CA, and by estimating a sediment budget for a full future implementation scenario of CA. Secondly, semi-quantitative interviews with 108 local farmers showed that rejection of CA was highly dependent on inadequate knowledge of the technique and on poor spatial proximity to the existing CA fields. A binomial logit model showed that perceived costs and benefits seem to balance each other. Also, the persisting agricultural tradition of multiple plowing causes some inertia for large-scale CA acceptance.However, since the majority of all interviewed farmers evaluate CA quite positively, and since the modelling results predict a large impact of CA on sheet and rill erosion rates, it could play an important role in future soil-water policy and agricultural intensification. Simulation of several policy scenarios shows that especially under a future wetter North-East-African climate, CA would be a beneficial alternative for the current plain tillage, as it will increase infiltration and keep runoff coefficients under control.
Boek: DesertLand, Abstracts
Pagina's: 108 - 108
Jaar van publicatie:2013