British Journal of Research www.britishjr.org British Journal of Research www.britishjr.org Original Article Polynomial Modelling of Allelopathic Effect of Topsoil Extract Isaac Owusu – Mensah* and Ebenezer Ekow Mensah Department of Science Education, University of Education, Winneba, Mampong – Ashanti, Ghana. *Corresponding author e-mail: iowusumensah@uew.edu.gh A B S T R A C T Objective: This paper seeks to model the allelopathic effect of topsoil extract transferred from Tectona grandis L. plantation on lycopersicum esculentum seed germination and seedling growth Research Methods: A mathematical model will be formulated using polynomial regression based on the data collected. This model was used instead of other proposed models because the relationship between the two variables was curvilinear. Cubic spline method was used to smooth the model to avoid oscillations between exact fit values. Computer program MATLAB was used in the analysis of the data. Results: It was found that the quartic polynomial regression model was the best fitted model for the collected data with least square parameters estimates given by Conclusion: This study has demonstrated that the allelopathic effects present in transferred topsoil samples of T. grandis on lycopersicum esculentum seed germination can be modeled using the quartic polynomial model for any concentration of topsoil between 0 kg and 7 kg. Keywords: Multiple regression model, Polynomial regression modeling, Root mean squared error, R-squared, Allelopathy, Topsoil extracts. INTRODUCTION Allelopathy is a natural phenomenon whereby one plant releases a substance which has inhibitory and stimulatory effects on other plants and micro organisms sharing the same habitat . A large number of plants have been identified as being allelopathic, and one of which is Tectona grandis Linn (Teak). The soil supporting the growth of teak have been found to contain maximum levels of exchangeable calcium and potassium the absence of which can result in restricted growth of roots, stems, leaves and many other parts of the plant . Allelopathic chemicals found in teak can be present in any part of the plant in addition