NUTRITIONAL EFFICIENCY OF Stryphnodendron polyphyllum SEEDLINGS IN FUNCTION OF NITROGEN AND PHOSPHORUS

Due to lack of agronomic studies with native species and the importance of an adequate supply of nutrients to plants, this study aimed to evaluate the effect of N and P on the concentration and nutrient content as well as the nutritional efficiency of barbatim\ue3o ( Stryphnodendron polyphyllum ) seedlings in Oxisol. The study was conducted in 8 dm3 pots and kept in a greenhouse. Were studied four doses of N (0, 20.82, 41.64 and 62.46 mg kg-1 N) and four doses of P (0, 41.72, 83.44 and 125.16 mg kg-1 P2O5) in 4x4 factorial in randomized complete block design with four replications. After 210 days after sowing was evaluated dry mass of shoots and roots and nutrient concentration in the plant, through these data were calculated the efficiency of absorption and utilization of nutrients. There was significant interaction between doses of N and P to the concentration of P, K, Ca, Cu, Mn and Zn in shoots and N, P, K, Ca, Mg and Fe in the root. In seedling nutrients N and Fe were influenced only by the isolated effect of N levels, and Mg content by isolated effect of P levels. The content of all nutrients in the shoot and root was significantly influenced by the interaction between doses of N and P. The maximum doses provided greater nutrient contents in shoots, except for N and K. The micronutrients content in the shoot increased as a function of both N and P and reduced the root, except Fe. The barbatim\ue3o seedlings were more efficient at absorbing N and Zn and using P and Mg. Comparing the content, N and Ca were the nutrients that most accumulated on the plant tissues, however, those who had lower (P and Mg) were the nutrients more efficiently used.Devido \ue0 car\ueancia de estudos agron\uf4micos com esp\ue9cies nativas e da import\ue2ncia do adequado fornecimento de nutrientes \ue0s plantas, objetivou-se neste trabalho avaliar o efeito de doses de N e P sobre o teor e conte\ufado de nutrientes, bem como na efici\ueancia nutricional de mudas de barbatim\ue3o ( Stryphnodendron polyphyllum ), em Latossolo Vermelho distrof\ue9rrico. O trabalho foi desenvolvido em vasos de 8 dm3 , mantidos em casa de vegeta\ue7\ue3o. Foram estudadas quatro doses de N (0; 20,82; 41,64 e 62,46 mg kg-1 de N) e quatro doses de P (0; 41,72; 83,44 e 125,16 mg kg-1 de P2O5), em esquema fatorial 4 x 4, no delineamento experimental de blocos casualizados, com quatro repeti\ue7\uf5es. Decorridos 210 dias ap\uf3s a semeadura avaliou-se massa seca da parte a\ue9rea e radicular e teor de macro e micronutrientes na planta; por meio desses dados foram calculados os \uedndices de efici\ueancia de absor\ue7\ue3o e utiliza\ue7\ue3o de nutrientes. Houve intera\ue7\ue3o significativa entre as doses de N e P para os teores de P, K, Ca, Cu, Mn e Zn na parte a\ue9rea e N, P, K, Ca, Mg e Fe na raiz. Na parte a\ue9rea das mudas, os nutrientes N e Fe foram influenciados somente pelo efeito isolado das doses de N, e o teor de Mg pelo efeito isolado das doses de P. O conte\ufado de todos os nutrientes, na parte a\ue9rea e na raiz, foi influenciado significativamente pela intera\ue7\ue3o entre as doses de N e P. As m\ue1ximas doses proporcionaram maior conte\ufado de macronutrientes na parte a\ue9rea, exceto N e K. O conte\ufado de micronutrientes na parte a\ue9rea aumentou em fun\ue7\ue3o das doses de N e P e reduziu na raiz, exceto Fe. As mudas de barbatim\ue3o mostraram-se mais eficientes em absorver N e Zn e utilizar P e Mg. Comparados ao conte\ufado, o N e o Ca foram os nutrientes mais acumulados nos tecidos da planta, contudo, os que apresentaram menor valor (P e Mg) foram os nutrientes mais eficientemente utilizados