Merit Research Journal of Agricultural Science and Soil Sciences (ISSN: 2350-2274) Vol. 7(7) pp. 087-093, July, 2019 Available online http://meritresearchjournals.org/asss/index.htm Copyright © 2019 Merit Research Journals Original Research Article Effect of Lime rates and Incubation Periods on the amelioration of Acidic Nitisols of Bedi area in Ethiopia Fekadu Mosissa 1 , Tesfaye Balemi 2 and Gemechu Keneni 1 Abstract 1 Holeta Agricultural Research Centre, P. O. Box 2003, Addis Ababa, Ethiopia 2 Debre Zeit Agricultural Research Centre, P. O. Box 32, Debre Zeit, Ethiopia *Corresponding Author’s Email: fekadu.mosisa@yahoo.com A study was conducted to determine the optimum lime/CaCO 3 rate and incubation period and exchangeable acidity equivalence for the amelioration of acidic nitisols collected from the central highlands of Ethiopia. A pot experiment was conducted at Holeta Agricultural Research Centre (HARC) in lath house using acidic soil samples collected from a depth of 0-20 cm from Bedi area, central high lands of Ethiopia. The treatments consisted of factorial combination of lime rates (0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 mg kg soil) and different incubation periods (7, 14, 21, 28, 35, 42 days). The treatments were arranged in RCBD with two replications. The result of the study showed that the soil pH consistently increased with the increase in lime application rates. There is no clear trend of incubation period effect on soil pH but higher pH was recorded after four weeks of incubation following lime application indicating that lime incubation period for optimization of soil pH would be one month before planting, if soil moisture level is kept optimum. The results showed that incubation method of calibrating soil pH using lime/ calcite completely changes soil pH from extremely acidic (3.85) to near optimum pH of 6 or 6.5 suitable for crop production. Incubation method ends up in higher rates of lime application compared to the exchangeable acidity based method. Results of the current incubation method study revealed that 12.6 and 16.8 t ha -1 needs to be applied to raise the soil pH from 3.85 to 6 or 6.5 which has to be applied four weeks before planning. Keywords: Incubation, lime requirement, acidic nitisol, exchangeable acidity, pH INTRODUCTION Nutrient deficiency, in part, is aggravated by soil acidity (Tolera Abera et al., 2006) which is the most wide spread problem in the Central Highlands of Ethiopia. In Ethiopia, large areas of highlands with altitude >1500 meter above sea level located in almost all regional states of the country are affected by soil acidity. According to EthioSIS (2014) and Behailu (2015) about 43% of the Ethiopian arable land is affected by soil acidity. In very acidic soils, all the major plant nutrients (nitrogen, phosphorus, potassium, sulphur, calcium, magnesium and also the trace element molybdenum) may be unavailable, or only available in insufficient quantities. As soils become more acidic, plants that are intolerant to acidic conditions would be negatively affected leading to productivity decline. Thus any attempt to adjust soil acidity primarily focuses on neutralizing the soil acidity though raising the pH so that toxicity of Al and Mn will be avoided and yet most macro nutrients become available for plant uptake (Fageria and Baligar, 2008). This can be achieved by adding lime to the soil and farmers can improve the quality of acidic soils through liming to adjust the pH to the levels needed by the crop to be grown and for most nutrients to be available (Mahesh, 2006).