Influence of the Nutritional Aspects on Initial Growth of African Mahogany (Khaya ivorensis A. Chev.)

Khaya ivorensis A. Chev. (African mahogany) is one of the most economically important forest species, since it is used in the international furniture market. However, little is known about its culture and nutritional requirements. This study aimed to assess the development of K. ivorensis plants subjected to different base saturations, as well as to different N, P and K levels. An 8-ha area was used, wherein 4 ha had base saturation increased to 55% and the remaining 4 ha to 75%. The experimental design adopted was randomized blocks with eight repetitions in a factorial scheme (4 × 4 × 4), being four N doses, four P doses and four K doses. The base saturation was assessed through the block effect. The root collar diameter and the plant height were measured 12 months after planting. Each experimental plot comprised six plants. The root collar diameter showed statistical differences between blocks and N doses. Only the NPK association showed statistical variation in plant height. However, a growth decreasing trend resulting from increased N doses was observed, as well as a growth increasing trend resulting from increased P and K doses. All treatments favored African mahogany growth. The most indicated base saturation was 55%, since there was no plant growth improvement when V% was increased to 75%. The excess of N impaired the growth of the species. The best treatment comprised 60 g urea, 240 g triple superphosphate, and 168 g potassium chloride.