PRODUCTION AND FOREST QUALITY OF Tithonia diversifolia (HEMSL.) A. GRAY UNDER DIFERENT COURT FREQUIENCIES

Abstract

The forage production and quality of Tithonia diversifolia (Hemsl.) A. Gray was evaluated under four cutting frequencies at 250 msnm between 2009 and 2011, in Bugaba, Chiriquí. An annual rainfall of 3700 mm and an average temperature of 28° C were recorded. The dry matter (DM) production and leaf/stem ratio were evaluated as production variables. The quality of the forage was evaluated according to the content of crude protein (PC), calcium (Ca), phosphorus (P) and magnesium (Mg) in leaf, whole plant and stem. Under a randomized complete block design with three replicates and cutting frequencies every 30, 45, 60 and 75 days, 35 cm long stakes of T. diversifolia were planted at 0,75 m between plants and rows. At sowing it was fertilized with 40, 30 and 20 kg/ha of N, P₂O₅ and K₂O, respectively. Maintenance fertilization was split in three annual applications of 20 and 40 kg/ha of N and P₂O₅, correspondingly. The analysis of variance showed a mean forage yield of 2,34 and 1,73 t DM/ha in the rainy and dry season, (P>0,05). The DM production was different between the cutting frequencies (P<0,01) with mean values ​​of 0,67; 1,67; 3,12 and 5,04 t DM/ha; for 30, 45, 60 and 75 days, respectively. The cutting frequency affected the leaf/stem ratio (P<0,05); not so, the content of PC, Ca, P and Mg (P>0,05). Regardless of the cutting frequency, we found a difference in PC content in leaf, whole plant and stem (P<0,05). It was concluded that increasing the cutting frequency showed an increase in dry matter production and a decrease in the contents of the crude protein.