Perfilhamento de espécies de Urochloa durante o inverno, primavera e verão

Abstract

The grasses of the Urochloa genus are the most commonly used for pasture formation in Brazil. In view of this, studies to understand the perennialization of these forage plants through tillering patterns are important because they allow for the identification and design of management practices aimed at increasing pasture forage production. This study was conducted to compare the tillering patterns of Urochloa species throughout the seasons. The experiment was carried out from September 2021 to March 2023 in an area of the Capim Branco Experimental Farm in Uberlândia, MG. This area consisted of 18 experimental plots, each measuring 6.25 m². The experiment followed a completely randomized design with repeated measures over time and three repetitions. Six forage grasses were evaluated: Angola grass (Urochloa mutica), Mozambique grass (Urochloa mosambicensis), signal grass (Urochloa decumbens cv. Basilisk), swamp bristlegrass (Urochloa arrecta), humidicola grass (Urochloa humidicola cv. Common), and ruzi grass (Urochloa ruziziensis cv. Kennedy). Basal tillering dynamics were assessed in two areas of 0.0177 m² per experimental unit. The time of year had a significant influence on all response variables. The factor "forage grass" individually influenced four variables: tiller appearance and mortality balance (BAL), population stability index of tillers (IE), tiller population density (DPP), and tiller survival rate (TSoP). There was no interaction between the studied factors and the response variables. The lowest values for the response variables BAL, IE, DPP, and tiller appearance rate (TApP) occurred in winter, spring/early summer, and late summer, while the highest values were observed in early spring and late summer. Tiller mortality rate (TMoP) and TSoP had intermediate values in winter. The lowest TMoP value occurred in early spring, and the highest values were in spring/early summer, mid-summer, and late summer. TSoP had the highest value in early spring and the lowest values in spring/early summer, mid-summer, and late summer. In general, signal grass, bristlegrass, swamp bristlegrass, humidicola grass, and ruzi grass have similar tillering patterns throughout the seasons. Angola grass has its perenniality compromised in well-drained Cerrado soils.