EFFECT OF METHODS OF TAPPING ON GUM YIELD OF ACACIA SEYAL VAR. SEYAL IN SOUTH KORDOFAN STATE, SUDAN

摘要

Acacia seyal var. seyal (talha) is an important multipurpose tree in the savanna zone of South Kordofan. The tree produces gum, which is collected from the natural exudation by the rural people. However, little information is available about the tapping possibility of A. seyal var. seyal. The objectives of this study were to determine the effect of tapping tools, position of tapping, date of tapping and intensity of tapping on A. seyal var. seyal gum yield, to find an improved procedure, suitable tool and optimum time for tapping the tree. Therefore, two experiments each with two factors/variables were carried out at Umfakarin forest reserve in 2001 02. In the first experiment the first factor was tapping tool, which was tested using four types (namely Makamak, Axe, Mohfar and Sonki). Sonki was developed by the gum research program for tapping A. Senegal whilst the axe is the traditional tool for tapping the gum arabic tree. The second factor was position of tapping, which was tested at four levels: lower stem (0-50 cm), middle stem (50-100 cm), higher stem (100-150 cm) and branch tapping. In the second experiment, the first factor was the date of tapping which was tested at three times (1st November, 15th November and 1st December), and the second factor was intensity of tapping, which was tested at four levels (2,4, 6 and 8 branches). The present study revealed the possibility of talha gum production by tapping A. seyal var. seyal. The tapping tools showed significant differences (P < 0.05) between the four tapping tools with respect to gum yield. The yield of Axe, Mohfar and Sonki was 58, 60 and 50% lower than that obtained using Makmak. The position of tapping had a significant effect (P < 0.05) on the amount of gum production; the middle stem tapping caused the highest gum yield with a total of 275 gree. The yields from the lower stem, higher stem and branch tapping were 25, 57 and 41% lower than that obtained from middle stem tapping. The interaction effect between the tapping tools and position of tapping was not significantly different. In the second experiment, the tapping date had a significant effect (P < 0.05) on the amount of produced talha gum. Trees in this experiment produced the highest gum yield when tapped on the 1st of November. However, the tapping intensity did not show significant effect on gum yield. Therefore, a tapping intensity of two to four branches is recommended in order to minimise the likelihood of damaging the A. seyal var. seyal tapped trees.