Acacia seyal Var seyal Del. and Acacia mellifera (Vahl) Benth, Nursery Establishment and the Effects of Land Preparation on their Growth in North West Sennar, Sudan

Abstract

Acacia seyal and Acacia mellifera are of great economical importance in the Sudan. Besides their many uses and values, Acacia seyal produces gum. Little or no experimentation work was done on their establishment, and artificial regeneration in the field. This study investigated their raising in the nursery and the effect of three methods of land preparation on their regeneration in the field. Four experiments were conducted: - Seed germination; using three shade conditions, three different pretreatments, soaking in concentrated sulphuric acid (5 minutes), boiling water (30 minutes), cold water (24 hours) and control for Acacia seyal. Acacia mellifera seeds were placed under different light intensity. - Seedling production of Acacia seyal; using different pretreatments, soaking in concentrated sulphuric acid (5 minutes), boiling water (30 minutes) and cold water (24 hours), three different light intensities (high light intensity, partial shade and low light intensity). - Seedling production of Acacia mellifera; using the three shade conditions, adopted for Acacia seyal. The parameters measured were above ground parameters (shoot height and shoot fresh weight (g) and below ground parameters (root length (cm) and root fresh weight (g)). - The effect of land preparation on artificial regeneration of Acacia seyal and Acacia mellifera; using three methods of land preparation: Furrowing method, (by using Moldboard plow), ditching method (by using Ditcher) and Disking method (by using wide level disc harrow) the parameters measured were above ground and under ground parameters. Pregermination treatments and shade condition had significant effect. Acacia seyal highest germination percentage was obtained by the use of concentrated sulphuric acid (100% for 5 minutes) under low light intensity. For Acacia mellifera, low light intensity also proved to be the best. The best condition for producing nursery stock of Acacia seyal is the use of concentrated sulphuric acid under high light intensity or partial shade. Also high light intensity and partial shade gave high growth of Acacia mellifera seedlings, probably due to the direct effect of light intensity on photosynthesis which increased with increased light, stomatal opening and chlorophyll synthesis. Medium tillage, by Moldboard plow proved to be the suitable technique for land preparation for both Acacia seyal and Acacia mellifera planting, compared to wide level disc harrow and Ditcher. Moldboard plow significantly affected growth of Acacia seyal and Acacia mellifera, probably because of the cut of soil which is medium and that affect the availability of nutrients, leads to higher water retention and improved soil condition.