Objective

: To evaluate the effect of planting density and regrowth age on the biomass production and bromatological composition of Tithonia diversifolia (Hemsl.) A. Gray.

Materials and Methods

: A trial was conducted at the Santa Lucía Experimental Farm, of the National University of Costa Rica. A split-plot, completely randomized design was used. The planting density constituted the main plot, and regrowth age, the subplot, with three repetitions per treatment. The planting densities 1, 2 and 4 plants/m2 were evaluated and three regrowth ages (42, 56 and 70 days) were studied, for a total of nine treatments. The variables biomass production and bromatological composition were evaluated. For the data processing a variance analysis was used.

Results

:The biomass production did not show significant interaction (p < 0,05) between planting density and regrowth age. The density of 2 plants/m2 and regrowth age of 70 days reached the highest production (0,46 and 0,48 kg DM/m2, respectively). The interaction of the factors planting density and regrowth age significantly affected the bromatological composition variables. The protein contents were between 8,9 and 17,5 %; the neutral detergent fiber, between 3,27 and 42,5 %, and the in vitro dry matter digestibility values, between 71,6 and 85,2 %.

Conclusions

: Planting density and regrowth age constitute variables that influenced biomass production and bromatological composition of the T. diversifolia forage. When it was cultivated at a density of 2 plants/m2, the highest biomass production was achieved. Meanwhile, with 4 plants/m2 competition for sunlight was generated, which limited biomass production.

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