A Espectrometria atômica na avaliação da marcha de absorção, acúmulo e exportação de nutrientes na espécie oleaginosa alternativa cártamo (Carthamus Tinctorius L.)

Abstract

Know the mineral uptake and nutrient accumulation are extremely important informations for the development of a culture, since these indicate the nutritional status of the plant and allow to an appropriate crop management. In this sense, this study determined the mineral uptake and nutrient accumulation the macronutrients (Ca, K and Mg) and micronutrients (Cu, Fe, Mn and Zn), using a flame atomic absorption spectrometry, in safflower alternative oilseed (Carthamus tinctorius L.) subjected to the crop rotation system with soybean and corn. To evaluate these factors, were collected shoot of 5 plants in different stages of development. However, after flowering the plant were separated into stems, leaves, flowers and seeds. The sample preparation consisted to weigh an amount of 0.2500 g (± 0.0001 g) of sample and subjected to acid digestion with HNO3:HCl [8:2 (v/v)] in an open system using a digester heating block.The determinations of macro- and micronutrients were made employing the main atomic lines of Cu (324.8 nm), Fe (248.3 nm), Mn (279.5 nm), Zn (213.9 nm), Ca (422.7 nm), K (766.5 nn) e Mg (202.6 nm). The accuracy and precision were evaluate by addition and recovery test and the results were consistent at 95% confidence. The safflower plants in crop rotation with soybeans accumulated until the flowering period contents of K > Ca> Mg> Fe> Mn> Zn> Cu, while with crop rotation with corn the accumulation followed like as K> Ca> Mg> Mn> Fe> Zn> Cu. After separation of the plant it was observed that higher levels of the nutrients were in the leaf and/or stem/leaf. The results obtained to safflower in crop rotation system with soybean and corn were compared with the control, and the results obtained were statistically different at 95% (t-test Student) for most elements. These results indicate that the previous culture positively influenced the absorption of nutrients, considering that the higher levels of nutrients were determined in the specie subject to crop rotation system.