Ecophysiology of Andropogon grass subjected to different cutting frequencies and intensities

Juliana R L Lima,Henrique N Parente,Rosane C Rodrigues,Clésio Dos S Costa,Francisco N De S Santos,Giovanne O C Sousa

doi:10.1590/1807-1929/agriambi.v24n9p610-615

Abstract

ABSTRACT The objective of this study was to evaluate the morphogenic and structural characteristics, and demographic patterns of Andropogon gayanus subjected to different cutting frequencies and intensities. A completely randomized design was adopted in a 3 × 2 factorial arrangement, corresponding to three cutting heights (50, 70, and 90 cm), and two cutting intensities (50 and 70%) with four repetitions, totaling 24 plots of 7.50 × 6.25 m. For morphogenesis, there was no interaction effect (P ≤ 0.05) of treatments on stem elongation rate, leaf appearance rate, and phyllochron rate. The highest rate of leaf elongation was observed at a height of 90 cm and cut intensity of 50%, with 1.69 and 0.84 cm tiller-1 d-1 of leaf elongation at heights of 50 and 70 cm, respectively. For forage production, there was no interaction (p > 0.05) between cutting intensity and cutting height. When the pasture was managed to a cutting height of 90 cm, there was a greater increase in dry leaf mass, stalk dry mass, dead forage dry mass, and total dry forage mass, which was 50.89% and 53.29% higher than pasture heights of 50 and 70 cm, respectively. There was no interaction between factors on demographic characteristics (p > 0.05). A cutting height of 70 cm with a cutting intensity of 50% is recommended when handling this grass.

Highlights

In the feeding of ruminants, plants of the Poaceae family are the most economical and practical part of the productive system, as long as the pasture is managed efficiently
The objective of this study was to evaluate the morphogenic and structural characteristics, and the demographic patterns of Andropogon gayanus grass subjected to different cutting frequencies and intensities
Grass managed at 50 cm height and 50% intensity showed a lower stem elongation rate (SER) (0.46 cm d-1)

Summary

Introduction

In the feeding of ruminants, plants of the Poaceae family are the most economical and practical part of the productive system, as long as the pasture is managed efficiently. Ecophysiology explains the morphophysiological responses of plants in environments in which they grow as a result of the management practices adopted. Understanding these changes facilitates the establishment of management practices consistent with the productive capacity of forage plants in a particular context (Pimentel et al, 2016). The frequency of defoliation or cutting changes the structure of the pasture, and the flow of biomass available to the animal via grazing, which can compromise the production and the nutritional value of grasses. The intensity of defoliation refers to how much the animal has removed from the plant in relation to what was made available for it to graze (Lemaire et al, 2011)

Objectives

Methods

Results