Plant Variation in Growth Rate

Abstract

Increased pasture yield is the traditional goal of the scientist. Certainly he has found grounds for optimism in the C₄ tropical grasses. Pennisetum purpureum yielded 86 t dry matter ha⁻¹ y⁻¹ over 3 years in the warm humid conditions of Puerto Rico, when cut at intervals of 9 weeks and liberally supplied with nitrogen fertiliser (Vicente-Chandler et al., 1959), and there are many reports of yields in the 30–50 t ha⁻¹ y⁻¹ range. It is unusual to find records of temperature C₃ pasture swards yielding even 23 t ha⁻¹ y⁻¹ under irrigated subtropical conditions (Cameron, 1964).