Structural characteristics of tiller age categories of continuously stocked marandu palisade grass swards fertilized with nitrogen

Abstract

The objective of this experiment was to evaluate the structural characteristics of young, mature and old tillers on continuously stocked marandu palisade grass maintained at 30 cm and fertilized with nitrogen. Treatments corresponded to three nitrogen application rates (150, 300 and 450 kg/ha of N) plus control (no fertilization) and were assigned to experimental units (1,200-m² paddocks) according to a completely randomized block design, with four replications. Measurements were performed during fall/winter 2007 and summer 2008. During summer, young tillers showed longer leaves and shorter stems relative to old tillers. During fall/winter, young and old tillers showed shorter leaves, while mature and old tillers showed longer stems. Tiller age interfered with the number of leaves per tiller mainly through variations in the number of expanding and senescing leaves during both fall/winter and summer. The structural characteristics of individual tillers are affected by plant age, with nitrogen favouring the production of leaf tissue in young tillers during summer.