EFFECTS OF MACRONUTRIENT DEFICIENCIES ON THE GROWTH AND VIGOUR OF KHAYA IVORENSIS SEEDLINGS

Nutrient deficiency may adversely affect the growth and quality of seedlings in forest nurseries. The objectives of this study were to determine the initial effects of macronutrient deficiency on the growth and vigour of Khaya ivorensis seedlings. One-month-old K. ivorensis seedlings were transplanted into plastic pots filled with acid washed sand. Six treatments were assigned to the seedlings––one control (T1) containing complete nutrient solution, and five treatments T2–T6, each lacking one of the following macronutrients N, P, K, Ca and Mg respectively. Watering with 100 ml of the specified nutrient solution or distilled water was done on alternate days. All treatments comprising eight replications were laid out in a complete randomized design. The visual deficiency symptoms and seedling growth were recorded monthly. Plant tissue nutrient content and dry weight were determined six months after transplanting. All treatments except for control induced deficiency symptoms. Macronutrient deficiencies induced visual deficiency symptoms, changes in seedling growth and tissue nutrient concentration. Lack of Mg and K adversely affected the tissue nutrient content of the seedlings.