Abstract

Ethiopian soil affected by strong acidity accounts for about 28% of the entire country and 43% of the total cultivated land. Soil acidity is expanding in scope and magnitude. To tackle the problem, lime addition is one of the solutions. The lack of soil specific lime recommendation method(s) to amend the increasing acidification problem has been one of the challenges to boost crop production. Therefore, a greenhouse experiment to select best-fit LR method(s) and calibrate on Luvisol was conducted. Different LR methods were evaluated to find out which of these methods most accurately predicted the LR in comparison with reference CaCO3‐incubation. The initial LR dose for incubation experiment was calculated using Shoemaker, Mc lean and Pratt (SMP) method to achieve a target pH of 6.0, followed by progressive incremental addition of lime. Then, the soil was incubated with different doses of CaCO3 for a period of five weeks to achieve different target pHs. The results of incubation were compared with the buffered and unbuffered LR methods. The CaCO3 incubation pH measurement results showed an increasing trend with an increasing amount of lime added. The LR prediction ability of exchangeable acidity and single addition Ca (OH)2 were the  least of all the methods tested for Luvisol, when compared to the reference method. Adams Evan and modified Mehlich LR predication are next to incubation in LR prediction for Luvisol. However, more researches that are detailed are needed to verify and synchronize the greenhouse results with field experiment in different agro ecologies to increase nutrient supply to the plant, water percolation and crop production.

Key words:  Acidity, luvisols, lime, lime requirement, Shoemaker, Mc lean and Pratt (SMP), modified Mehlich.