Structural Characteristics of Mulato Grass I under Different Cutting Heights

Abstract

This work aimed to evaluate the effects of different individual heights of cut on structural charac-teristics of Brachiaria hibrida cv. Mulato I in four periods of the year. The study was carried out at the Fazenda Experimental Vale do Acaraú, in Sobral, Ceará, Brazil, from January to December, 2008. The experimental design was a split plot, with the plots representing four pasture condi-tions through manual cuts of 10 cm, 20 cm, 30 cm and 40 cm heights, which were done every 30 days. Each treatment had three replications. The subplots were represented by four periods of evaluation: January-February-March, April-May-June, July-August-September and October-No-vember-December. Fertilization was performed with 350 kg of N/ha, divided into monthly appli-cations. Irrigation was conducted in alternate days during the dry season. The variables studied were: mean height before cutting (cm); dry matter content (%); total dry matter production (t/ha); percentage of leaves; percentage of stems; percentage of dead material; leaf blade/stem ratios; number of total leaves per tiller; number of live leaves per tiller; average size of leaves; and tiller density. Cutting at 10 cm caused a decrease in total dry matter production, underestimating the potential production. Cutting heights between 20 and 30 cm contributed positively to increase the total number of leaves, number of green leaves, average size of the leafs and total dry matter pro-duction. Under the present experimental conditions, cutting around 40 cm was not recommended because of a decreasing in the leaf/stem ratio and a increasing in stem fraction and dry matter content, compromising the structure of the canopy.