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Universität für Bodenkultur Wien (2013)

Evaluation of traditional and agroforestry land cultivation and compensatory liming on soil nutrient depletion, acidification and crop yields in Kuashini and Kantaye watersheds, Northwestern Ethiopia

Zeleke, Shimelash Yeshaneh

Titre : Evaluation of traditional and agroforestry land cultivation and compensatory liming on soil nutrient depletion, acidification and crop yields in Kuashini and Kantaye watersheds, Northwestern Ethiopia

Auteur : Zeleke, Shimelash Yeshaneh

Université de soutenance : Universität für Bodenkultur Wien

Grade : Dr. nat. techn. 2013

Résumé
In two watersheds, Kuashini and Kantaye, in the Amhara Region the influence of land use, slope position and biomass removal and compensatory liming on soil nutrient status, soil acidity and crop yield of major cereal crops were investigated. To evaluate the effects of different land use types (natural forest NF, agroforestry TOF, cultivated land CL) soil nutrient status and acidity, soil samples from 0-15 cm and 15-30 cm depth were taken. The soil analyses included texture, pH-values in H2O und 0,1M CaCl2, tN, tC, tP, exchangeable cations (Al, Ca, Fe, K, Na Mg, Mn), CEC and base saturation percentage. The grain and straw yields of crops grown under trees (TOF) and on CL without trees were compared. The cultivated crops were maize under Croton macrostachyus in Kuashini and triticale under Juniperus procera in Kantaye. In Kantaye the pH-value (CaCl2) of the topsoil was 6.5 under TOF, 4.8 under cultivated land. The organic matter (SOM) content under TOF (7.5 %) was significantly higher than under cultivated land (5.6 %). CEC and tN followed the same trend. In Kuashini pH was almost the same under TOF (4.6) and CL (4.5). SOM content of the topsoil was 6.6 % under TOF and 5.6% under CL. In both watersheds the crop yield was higher under TOF than under CL. The grain and straw yields of maize of as well as triticale were higher in TOF than in CL plots. In the second experiment maize, teff and wheat were grown in different slope positions. The yield and major nutrient contents of grain and straw were determined and used to calculate the net acidification resulting from biomass removal and the amount of lime required to compensate it. Soil samples were taken and analyzed as mentioned above. To compensate the H+-input by the grain harvest of 1 t of maize 43 kg, of teff 48 kg and of wheat 52 kg lime are required. In a third experiment the yield of wheat (Kantaye), maize and teff (Kuashini) with the application of 25 %, 50 % and 100 % of the lime rate recommended for each crop was determined. Soil samples were taken from 0-20 cm depth to study the effects of crop harvest and liming on soil acidity and nutrient status. A cost-benefit analysis was carried out to determine the economically justifiable lime rates for the different crops. Farmers were interviewed about their perception of soil nutrient depletion and acidification problems and management practices to maintain soil fertility. To maintain soil fertility, the expansion of agroforestry systems, leaving crop residues on the field, the use of manure or compost and the application of lime to replace nutrients removed with crops are recommended

Mots clés : Bodenversauerung / Nährstoffverlust / Biomassenentzug / Agroforestry / Kalkung — Soil acidification / nutrient depletion / crop harvest / agroforestry / liming

Présentation (österreichischen Bibliothekenverbundes)

Page publiée le 12 décembre 2015, mise à jour le 13 mars 2019