Efeito da adubação na nutrição e na colonização radicular por fungos micorrízicos arbusculares do camucamuzeiro (Myrciaria dubia (H.B.K.) McVaugh e da aceroleira (Malphigia punicifolia L.) em um Latossolo da Amazônia Central

Abstract

The low fertility of the majority of Amazonian uplands soils allied to the deficiency resource of the majority of small farmers influence directly in the development and local agriculture sustainability. One strategies to reach the sustainability is to maximize the beneficial microorganisms use of the soil, as the arbuscular mycorrhizal fungi (AMF), which are capable to increase the site mineral nutrients and water absorption to host plants. In addition, the foliar fertilization is a economic practice that has high index of mineral nutrients use for the plants, due to lower amounts of the product used. In this manner, informations about soil microbiology and the acerola and camu-camu behavior in differents treatments can contribute to develop the production of these two potencial fruit species to local agriculture. This research had as objective to evaluate the fertilization effect in the nutrition and AMF colonization of the camu-camu and acerola tree cultivated on yellow oxisol located in the Brasileirinho Agricultural Community, Manaus. In fields conditions, it was evaluated the foliar macro e micronutrients contents, the mycorrhiza colonization rates and the spores number of both the species on three collect times. The experimental design was randomized blocks with a 3 x 10 split plot scheme to camu-camu tree. The factors means three collect times (08/04/06, 15/07/06 e 07/11/06) and ten treatments with chemical, foliar and organic fertilization. To acerola tree, 3 x 9 split plot scheme, with three collect times (21/02/06, 15/06/06 e 09/11/06) and nine treatments. There were significant variations in the acerola foliar contents in differents treatments. The plants that received the treatments with chemical fertilization presented the higher leand Ca, Mg, K, P and N. The plants that received the treatments with foliar fertilization presented the highest Fe, Mn and Zn leand contents. This fact provides the aiding on micronutrients absorption through the highest effectiveness of foliar fertilizer. There were variations in foliares contents of camu-camu in differents treatments, with exception of the N and Mn contents. The plants that received the treatments with organic fertilization presented the highest Ca, Mg, P and K averages. The Fe, Mn and Zn leand contents were favored by foliar fertilizer applications, exception to Mn, that did not present significant variations. In Authoress: THANA ESASHIKA BEZERRA Adviser: Dr. LUIZ ANTONIO DE OLIVEIRA acerola, the treatment with chemical fertilizer provided the hightest Ca, Mg, K, P and N contents without differing of the contents provided by organic fertilization. The organic fertilization is more economical than others fertilization to the small farmers. The foliar fertilizer was efficient to micronutrients, proving to be a quick, economical and of easy application. In camu-camu, the treatment with organic fertilization was adjusted, because it had provided the highest Ca, Mg and K contents. To P, Fe, Zn and Mn nutrients, the treatments with foliar fertilizer showed efficient. On acerola, the association with mycorrhiza fungi showed positives correlations with leand nutrients, but the correlation rate was very low. Thus, there was no efficient benefice of the plant-fungi symbiosis. In both the cultures, the fertilization and the P concentration in the soil can have influenced, of negative form, in roots colonization by mycorrhizal fungi. Besides, to camu-camu and acerola tree, the organic fertilization, generally, provided the better results to the macronutrients, and the foliar fertilization to the micronutrients. Key words: Amazonian Fruit Species, Foliar Fertilization, Plant Nutrition, Arbuscular Mycorrhizal Fungi (AMF).