| dc.description.abstract |
The macaw palm (Acrocomia aculeata (Jacq.) Lodd. Ex Mart.) is a palm native to Brazil with potential for vegetable oil production compared to african palm (Elaeis guineensis Jacq.). The advantage of macaw palm regarding african palm is its adaptability to various soil and climatic conditions. However, until recently, this plant was operated exclusively in extractive system, with few phytotechnical studies about the species. Moreover, for the macaw palm is established as a feedstock for biodiesel production, is essential to meet two basic requirements: production scale and competitive price. For this it is necessary to develop culture systems, which in turn involves knowledge of the nutritional requirements of the plant. This study aimed to evaluate the response of macaw palm to the absence of mineral nutrients (characterization of nutritional deficiency) and different levels of fertilization in plants grown in the nursery and in field conditions. For this, there were three unpublished experiments with this plant: Experiment 1 - Getting the symptoms of nutrient deficiency and nutrient content related to these minerals. Two months old macaw palm seedlings were acclimated in static aerated nutrient solution until the issuance of the first pinnate leaf (definitive leaves), when the seedlings were six months old and the treatments were applied (omission of mineral nutrients: N, P, K, Ca, Mg, S, Cl, Fe, B, Cu and Zn). After six months of cultivation under the influence of treatments (1 year old seedling) chemical characteristics (levels of mineral nutrients in plant tissue) and plant parameters (leaf number, shoot length and root diameter of the bulb and dry weight of the bulb, root and leaf) were evaluated. As a result, we obtained the characterization of mineral deficiency, the nutrient content in dry matter, nutrient accumulation and sensitivity of the macaw palm plant to the omission of nutrients. Experiment 2 - Evaluation of substrates combination of lime and phosphorus fertilization coverage for macaw palm seedling production. Three trials were conducted involving: evaluation of substrates for macaw palm seedling production; evaluation of the effect of lime and phosphorus in plant propagation and evaluation of the frequency of top-dressing with N, K and Mg. Three months old seedlings of macaw palm were treated as described above and evaluated for chemical and plant parameters. As a result, we obtained a reference to substrate composition, lime, phosphate and topdressing for macaw palm seedling production. Experiment 3 - Evaluation of macaw palm response to five levels of N and K fertilization for two years, growing in the field. Eight months old macaw palm seedlings were planted in the field with the same initial fertilization for all treatments. At the beginning of the rainy season subsequent treatments were induced (N and K increasing). In the second year of cultivation, plant height, leaf number, force and foliar concentrations of mineral nutrients were evaluated. As a result, we obtained a reference on the macaw palm response to increasing doses of N and K at the field level as well as the first parameters of foliar cultivated plants. In general, the results obtained from the three experiments allow making a fertilizer recommendation for macaw palm seedling production, guide the fertilized field and compare the nutritional status of grown macaw palm plants. |
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