Cut management of Tithonia diversifolia as a function of regrowth ages: a physiological and morphological approach

ABSTRACT Tithonia diversifolia is exploited in tropical countries as a forage. However, there are no studies on its ecophysiology and relationship with the management of the species. This study aimed to evaluate the post-cut regrowth ages of T. diversifolia in terms of physiological and productive behavior and its implications for forage management. A completely randomized design was used, with four replications and ten regrowth ages of T. diversifolia at 21, 28, 35, 42, 49, 56, 63, 70, 77, and 84 days after the cut. Photosynthetic rate and stomatal conductance showed relatively low values at the beginning of growth and maximum values at 39 and 51 days of regrowth and subsequent decline. WUE was higher at 45 days of regrowth. A linear reduction in the function of the plant's age was observed for transpiration. Leaf dry mass reflected the balance of physiological processes, with a gradual increase and subsequent decrease in net production. A period of 15 days, between 49 to 63 days of regrowth, is recommended for using T. diversifolia as forage. This period associates leaf availability, higher carbon fixation, more significant WUE, and little senescent material (<5% of the plant's total dry mass) from T. diversifolia.