Effects of conservation agriculture on runoff,soil loss and crop yield under rainfed conditions in Tigray,Northern Ethiopia |
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| Authors: | Tesfay Araya W M Cornelis J Nyssen B Govaerts H Bauer Tewodros Gebreegziabher Tigist Oicha D Raes K D Sayre Mitiku Haile J Deckers |
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| Institution: | 1. Department of Crop and Horticultural Science, Mekelle University, PO Box 231, Mekelle, Ethiopia;2. Department of Soil Management, Ghent University, Coupure Links 653, B‐9000 Gent, Belgium;3. Department of Geography, Ghent University, Krijgslaan 281 (S8), B‐9000 Gent, Belgium;4. International Maize and Wheat Improvement Centre (CIMMYT), AP 6‐641, Mexico DF 06600, México;5. Department of Earth and Environmental Sciences, K.U.Leuven, Celestijnenlaan 200E, B‐3001 Heverlee, Belgium;6. Department of Land Resources Management and Environmental Protection, Mekelle University, PO Box 231, Mekelle, Ethiopia |
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| Abstract: | The aim of conservation agriculture (CA) is to improve soil quality and crop yield whilst reducing runoff and topsoil erosion. An experiment was carried out in a rainfed field using a permanent raised bed planting system for 3 yr (2005–2007) in Adigudem, northern Ethiopia in order to evaluate the effect of CA on runoff, soil loss and crop yield. CA practices were introduced in fields with Vertisols in a randomized complete block design on permanent 5 × 19 m plots. Three treatments were evaluated: (1) conventional tillage (CT) with a minimum of three tillage operations and removal of crop residues, (2) terwah (TER) that was similar to CT except that contour furrows were included at 1.5 m intervals, and (3) derdero+ (DER+), which consists of permanent raised beds with a furrow and bed system, retention of 30% of standing crop residues and zero tillage on the top of the bed. All ploughing as well as the maintenance of the furrows of the permanent raised beds was done using a local ard plough called maresha. Results from monitoring over 3 yr showed that soil loss and runoff were significantly higher (P < 0.05) in CT followed by TER and DER+. Average soil losses of 5.2, 20.1 and 24.2 t/ha were recorded from DER+, TER and CT, respectively. Runoff was 46.3, 76.3 and 98.1 mm from DER+, TER and CT, respectively. Grain yield was significantly lower (P < 0.05) in DER+ under teff in 2006, probably due to the high sensitivity of teff to weeds. The yield of wheat in 2007 was significantly higher in DER+ followed by TER. The terwah system is recommended as a first measure for wider adoption to reduce runoff and soil loss and to increase crop yield. The long‐term goal is to achieve a derdero+ system, i.e. a permanent raised bed planting system along with the application of crop residues. |
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| Keywords: | Terwah derdero permanent raised bed crop residues wheat teff conservation agriculture |
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