Application of selected non-linear functions to describe oriental goat’s rue (Galega orientalis Lam.) growth

Abstract

In the study it was attempted to describe the growth of oriental goat’s rue (Galega orientalis Lam.) by means of a logistic function, Gompertz function and Richards function. Analysis of data was based on measurements of stem lengths of oriental goat’s rue (Galega orientalis Lam.) cv. Gale which were taken during a four-year period as part of a long-term experiment set up in 2009 at the experimental site of the University of Natural Sciences and Humanities. From 2009 to 2012, 70 plants were randomly selected every seven days from the start of growth to the stage of full maturity of pods. The beginning of growth was assumed to be the moment of forming leaf buds on root necks of the plants which overwintered. The study demonstrated that the functions described the empirical data well as the coefficients of determination obtained ranged from 9 to 99%, depending on the growing season. The estimated function parameters indicate that both plant height and growth rate were affected by thermal conditions and moisture during the growing season. The maximum growth rate ranged from 2.18 to 4.04 cm per day. Also the inflection point, the point at which plants grew the fastest, depended on the conditions of the growing season.

Keywords

• oriental goat’s rue
• gompertz function
• logistic function
• richards function
• growth rate