Características morfogênicas e estruturais do capim-pangolão (Digitaria pentzii stent.) submetido a diferentes manejos de corte

Abstract

Ptarmigan grass (Digitaria pentzii Stent.) is a perennial, stoloniferous, drought-tolerant and intense grazing grass, and has reached high dry mass under semi-arid conditions. The objective of this study was to evaluate the management of cuttings in the morphogenetic and structural characteristics of pangolão grass. The experiment was conducted from July to November, 2018, in the experimental area of the Group of Studies in Forragicultura, Federal Rural University of Pernambuco, Academic Unit of Serra Talhada, micro region of Sertão do Pajeú. The experimental design was a randomized complete block design with 3 x 3 factorial design, with three pre-grazing heights (30, 40 and 50 cm) and three post-grazing (10, 15 and 20 cm) heights, with four replicates. The foliar leaf length, leaf blade width, stem length, stalk diameter, number of tillers, number of leaves: expanded, growing, senescent and leafy, were monitored every seven days withmonitoring of the growth of pangolon grass. dead Weighed fresh and dry mass of leaf blade, stem and panicle. The percentages of the morphological components were determined. The leaf area was estimated in a non-destructive manner, based on the linear length and width dimensions of the leaf blade. The data of the evaluations were submitted to normality test, homoscedasticity and to the analysis of variance by Test F. When the F was significant, the means of the treatments were compared by the Tukey test at 5% of probability. The pre-grazing height 30 cm gives higher dry mass values. The pre-grazing height of 50 cm presents a larger number of tillers and senescent leaves. The post-grazing at 10 cm of height presents higher phytomass values of the pangolão grass, independently of the pre-grazing height. The post-grazing at 15 and 20 cm associated with the pre-grazing of 50 cm provides a greater number of dead leaves. The pre-grazing height of 30 cm and post-grazing of 10 cm is presented as the best cut management for the pangolão grass. The product of the maximum leaf width length is a suitable parameter for use as an independent variable in the prediction of the leaf area of the pangolão grass, through regression models. The power model, Y = CL1,007, can be used to determine the leaf area of the pangolão grass, independently of the cutting height, with bases on the leaf blade length and width values of thisspecies.