Abstract
Field and laboratory experiments were carried out at Ladoke Akintola University of Technology, Ogbomoso, Nigeria in 2001 and 2002 to assess the effects of age on the nutrient concentration and manorial properties of Tithonia diversifolia (Hemsl.) A Gray. Tithonia plants at 2, 4 and 6 of age and at flowering were harvested, processed and subjected to plant tissue analysis. Result showed that N, P and K decrease with age of Tithonia while C, Ca, Crude fibre, C:N ratio and organic matter increased with age. The highest values of N (2.10%), P(0.89%) and K (3.92%) occurred in 2 weeks plant (for N and P) and for 4weeks plants (for K). Ca was highest (3.28%) in 6weeks plant. Tithonia was very low in Mg with the highest value (0.0066) occurring in 2 and 6weeks plants. These values of N, P, Ca and Mg were however not significantly (P< 0.05) superior to those of 4 weeks plants. It is concluded that Tithonia is best cut and incorporated into the soil at 4 week of age for best manurial value.
Keywords: Tithonia diversifolia, manurial properties, nutrient content, age of plant.