Effects of nutrient deficiencies on the growth potential and vigour of khaya senegalensis (desr.) A. Juss. seedlings in South West Nigeria Nursery

Abstract

Successful afforestation and reforestation projects are dependent on various factors, but the quality of seedlings placed in the field is extremely important as fertile growth medium contributes to seedling vigour in the nursery. The study investigated the nutrient requirements for optimum growth of K. senegalensis and their deficiency symptoms in a bid to enhance vigorous seedlings. One-month-old seedlings of K. senegalensis were transplanted to polythene pots filled with washed and sterilized 4kg river sand for application of different nutrient solutions (NS). Treatments include Deionized water [No nutrient (control)] (T1), Standard NS of known nutrient concentration (complete nutrients) (T2), NS lacking K (T3), NS lacking Ca (T4), NS lacking Mg (T5), NS lacking N (T6), NS lacking P (T7), NS lacking S (T8) and NS lacking Fe (T9) in ten replicates laid in a complete randomized design. Visual deficiency symptoms were observed and recorded based on unusual growth patterns and coloration. Data on seedling height, stem diameter and number of leaves were collected and subjected to analysis of variance (ANOVA). The symptoms on T6 were first observed three weeks after transplanting when the older leaves changed colour to pale green. T7 older leaves and Stems turned to dark green and had stunted growth. Curling of leaf tips, brown scorching and chlorosis were observed in T3. There were significant differences among the treatments in growth variables at (P< 0.05). It is found that different components of nutrient solution play significant roles in the growth and development of K. senegalensis seedlings. For optimum growth and development, planting of k. senegalensis seedlings in nutrient-rich soil are recommended.