Caracterização nutricional do nim em plantios no Brasil Nutritional characterization of neem plantations in Brazil

No Brasil são incipientes os estudos sobre os aspectos nutricionais do cultivo do nim. Propôs-se, neste trabalho, determinar os teores foliares de macronutrientes em plantios de nim estabelecidos em oito Estados do Brasil e correlacioná-los com os nutrientes disponíveis na camada de 0-20 cm de profundidade dos solos sob os plantios amostrados. De cada plantio foram coletadas folhas de nove árvores das partes média/superior e média/inferior da copa, as quais foram misturadas, formando duas amostras compostas denominadas folhas da copa média/superior (FCMS) e folhas da copa média/inferior (FCMI). Para análise de variância dos teores foliares de nutrientes utilizou-se o delineamento inteiramente casualizado, com decomposição total dos graus de liberdade visando ao efeito local de plantio, idade de plantio e posição na copa, sendo a comparação de médias realizada pelo Teste de Duncan (p < 0,05). A amostragem foliar nas árvores de nim depende, quando feita na posição mediana subdividida em FCMS e FCMI, entre outros fatores, da mobilidade do nutriente e da condição de luminosidade do plantio. Os teores foliares de Ca apresentam indícios de ser o nim uma espécie calcícola. O nim é eficiente na absorção de N, P e Ca. O K do solo apresenta correlação positiva com o K das FCMI.<br>In Brazil, there are very few studies about nutritional status of neem. This study aimed to determine the contents of macronutrients in leaf in neem plantations established in different locations in eight states of Brazil, and perform correlations with the available nutrients in the respective soils under the sampled plantation. From each plantation the leaves were collected from nine trees, from the middle superior and middle inferior part of the crown. Each part of the crown of the nine trees were mixed, forming two composite samples and were nominated as leaves from the middle superior crown (FCMS), and middle inferior crown (FCMI). At the time of leaf sampling, the soil was collected in 0-20 cm depth. For variance analysis of the nutrient contents of leaf, a completely randomized design was used, applying total decomposition of the degrees of freedom for stand localization, stand age and crown position effect, being the mean comparisons performed by the Duncan test (p < 0,05). Additional correlation and cluster analysis were applied integrating soil data. The leaf sampling of neem trees, when realized in the middle of the crown subdivided in FCMS and FCMI depends, among other factors, on the nutrient mobility and on the light conditions of the stand. The leaf contents of Ca show indications that the neem plant could be a calcicole plant, and efficient in N and P absorption. The soil K content is positively correlated with the K content of the FCMI position