Tillering dynamics and population stability of three tropical forage grasses cultivated as pure or mixed stands

Abstract Studies on tillering dynamics are essential to understand the aspects underlying the persistence and adaptation pathways of grass communities, especially in more complex multispecific pastures. This study aimed to assess the tillering dynamics and population stability of Andropogon gayanus cv. Planaltina (PG), Megathyrsus maximus cv. Massai (MG) and Urochloa brizantha cv. BRS Piatã (PP) grown as monocultures and as a mixture. The treatments corresponded to three grasses described above. Sixteen 180 m 2 plots were randomly assigned and managed intermittently under manual harvest at pre- and post-harvest heights of 35 and 17.5 cm, respectively, for two years. During autumn/winter/early spring, when resource availability is limited by abiotic factors, pasture population stability was ensured by the conservation strategy of all species, mainly through the high tiller survival rate (85.5 ± 0.32). In late spring and summer, the capture strategy was prioritized for all species, with stability ensured through high tiller appearance rates (30.3 ± 0.80 and 40.4 ± 1.47, respectively), which compensated for the high tiller death rate (28.7 ± 1.10) and resulted in greater species turnover during these both seasons. The association among PG, MG and PP in a mixture allows species to coexist with relatively stable populations and tillering dynamics, similar to their monocultures. These findings represent a step forward in our understanding of mixed swards stability and indicate that such associations could be viable alternatives to palisadegrass monocultures in tropical regions. Further research should test this mixed sward under grazing, during medium to long-term.