American-Eurasian J. Agric. & Environ. Sci., 19 (4): 312-325 2019 ISSN 1818-6769 © IDOSI Publications, 2019 DOI: 10.5829/idosi.aejaes.2019.312.325 Corresponding Author: Tesfaye Wakgari, College of Natural Resource Management and Veterinary Science, Ambo University, P.O. Box: 226, Ambo, Ethiopia. 312 Effects of Subsoiling and Organic Amendments on Selected Soil Physicochemical Properties and Sugar Yield in Metahara Sugar Estate Tesfaye Wakgari, Kibebew Kibret, Bobe Bedadi, Melesse Temesgen and Teklu Erikossa 1 2 2 3 4 College of Natural Resource Management and Veterinary Science, 1 Ambo University, P.O. Box: 226, Ambo, Ethiopia School of Natural Resources and Environmental Sciences, 2 Haramaya University, P.O. Box: 138, Dire Dawa, Ethiopia Department of Mechanical Engineering, Engineering Faculty, 3 Addis Ababa University, P.O. Box: 271, Addis Ababa, Ethiopia Integrated Water Management Institute, P.O. Box: 153, Addis Ababa, Ethiopia 4 Abstract: Sugar industry residues such as filter cake and vinasse often available at a very close distance, with minimum cost and subsoiling, can be used to improve and sustain soil physicochemical properties and in turn to ameliorate compaction effects of Ethiopian Sugar Estate soils. This field experiment was conducted in 2016 on light soil management unit group at Metahara Sugar Estate with the objective of assessing the effects of different rates and types of organic amendments and subsoiling on some physicochemical properties of soils. Field experiment was laid in a randomized complete block design and replicated three times. Four levels of filter cake (0, 15, 30, 45 t ha ), four levels of compost (0, 11.03, 22.07, 35.86 t ha ) and four levels of vinasse 1 1 (0, 35, 70, 105 m ha ) in combination with subsoiling operation at a depth of 70 cm with 91 cm shank distance 3 1 were studied as treatment combinations at Metahara Estate. The results of the study revealed that maximum bulk density and penetration resistance were recorded for the control plots. It was observed that minimum bulk density and penetration resistance values were recorded in plots that were subsoiled. Higher concentration of soil organic carbon, available P and total N were observed in plots that received organic amendments. The maximum sugar yield (18.95 t ha ) was recorded in subsoiled plots followed by the treatment that have 1 filter cake compost rate of 22.07 t ha . Therefore, it can be concluded that depth targeted and site specific 1 subsoiling operation can be used when there is any problem related to compaction and severe plough pan within the underlying soil layers, which could cause restricted root growth. Moreover, soil compactibility due to use of heavy machinery during sugarcane production can be reduced by incorporating 30 and 22.07 t ha 1 filter cake and filter cake compost sugarcane residues, respectively, before Magnum case III 315 tractor passes. There is a need for further study with different dose of the residues on soil management unit groups of the other estate soils and Metahara heavy soil management unit. Key words: Improvement Measures Filter Cake Vinasse Filter Cake Compost Subsoiling INTRODUCTION 3 separate locations across the country. The increase in Sugar industry development in Ethiopia was initially in increased quantity of waste products. The major waste started in Wonji-Shoa in 1954. Nearly 60 years since the products from sugar processing and alcohol manufacture industry started in an organized manner, four small to are bagasse from the cane crushing operation, filter medium sized sugar factories with a combined daily cake from the cane juice filtration, molasses and vinasse crushing capacity of about 12, 500 tons were installed in from distilleries. The sugarcane industry in Ethiopia, in sugarcane and sugar production has inevitably resulted