Reduction of sward height in the fall/winter as strategy to optimize tillering in Urochloa brizantha syn. Brachiaria brizantha

Abstract

The evaluation of tillering dynamics is important to understand the effects of defoliation strategies and climate on forage production and perenniality of the sward. Therefore, the objective of this study was to identify defoliation strategies that optimize the tillering of marandu palisadegrass through the year. Three defoliation strategies were evaluated: sward with 15 cm in fall/winter and 30 cm in spring/summer; 45 cm in fall/winter and 30 cm in spring/summer; and 30 cm during the entire experimental period. Tiller appearance (TAR), mortality (TMR), and survival (TSR) rates; the balance (BAL) between TAR and TMR; stability index (SI); and tiller density (TD) were evaluated monthly and grouped into the seasons: winter, early spring, late spring, and summer. A completely randomized design with four replicates was adopted. In summer and early spring, TAR, SI, and TD were higher than in winter and late spring. Winter was characterized by unfavorable climatic conditions to plant growth, such as low precipitation and temperature, and in summer there was a short period of rainfall scarcity. The defoliation strategies in fall/winter did not influence tillering dynamics. The marandu palisadegrass with 15 cm in fall/winter showed a greater TD than that with 45 cm. To increase TD, marandu palisadegrass can be maintained at 15 cm in fall/winter, and at 30 cm in summer.