Adjustment to a mathematical model, comparison of the growth curves and morphological characteristics of four Urochloas from an in vivo collection established in Antioquia, Colombia

Abstract

The aim of this study was to adjust the growth curves of four Urochloas using a mathematical model that allows the inter comparison. The variables of height (cm), air temperature (°C), precipitation (mm) and pasture age (days) were evaluated. The growth of each species was analysed in the statistical software R-Project. The growth data of the species were adjusted with the use of the quadratic model yt = β₀ + β₁ t - β₃ t², with coefficients of determination (>0.9) and a value of p<0.001. As a result, Urochloa brizantha cv Piatá presented an R² = 0.9859 and was the species most positively influenced in its growth by the effect of age (days), followed by U. decumbens, U. mutica and U. brizantha cv Toledo, the latter with the least adjustment. Precipitation influenced the growth rate of U. mutica while temperature had no influence on the growth of the species. The curves were fitted to quadratic models, which indicates that its growth can be compared and predicted over time, which facilitates its management and optimal use.