Introduction. Chlordecone (CLD), an organochlorine formerly used to control the banana black weevil, is strongly adsorbed on soils, particularly on andosols. A simplified analytical procedure for the quantitative determination of chlordecone residues in water and micro-samples of soil and plants was compared with a standard method. Materials and methods. The procedure combines a simplified sampling protocol and a 10-min solid phase microextraction (SPME), followed by gas chromatographic separation (GC) and mass spectrometric (MS and MS/MS) identification. Quantitation of CLD used a standard addition method with zero extrapolation. First, seventy samples were analysed using the proposed method and the standard method based on hot solvent extraction. Second, fifteen soil samples were analysed with two SPME methods followed by GC-MS but using CLD labelled with C13 as an internal standard or the proposed method. Results and discussion. The detection (LOD) and quantitation (LOQ) limits of our SPME extraction procedure were determined for GC-MS and GC-MS/MS with water, plant (pineapple roots) and soil samples: in water for MS/MS, LODMS/MS-water = 0.5 ng×L–1, LOQMS/MS-water = 2.0 ng×L–1; in andosol for MS/MS, LODMS/MS-soil = 15.0 ng×kg–1 dw, LOQMS/MS-soil = 80.0 ng×kg–1 dw. Data from the seventy contaminated soils obtained with the proposed method and the standard method showed a correlation coefficient of r = 0.86. Data obtained by the two SPME/GC-MS quantitation procedures showed a correlation of r = 0.8073. Conclusion. The method proposes a simplified sample preparation and extraction of CLD in water, plant and soil samples, with no solvent manipulation and which is not time-consuming. The LOD and LOQ were similar to those obtained with other currently used methods. The method is reliable and accurate and may be considered as a good tool for research purposes.

Introduction. Mineral status related to micronutrients and sodium is important to obtain high yields, despite the fact that no standardized contents have been established for yellow passion fruit. Biofertilizers have emerged as an important component of the integrated nutrient supply system aiming at an environmentally better nutrient supply because they have a direct action on micronutrient uptake. In this context, the objective of our research was to evaluate the micronutrient and sodium foliar contents of yellow passion fruit plants fertilized with two different biofertilizers in Brazil. Materials and methods. A randomized block design with treatments distributed in a factorial arrangement (2 × 5) referring to two biofertilizers (simple and enriched with Zn, Mg, Mn, Cu, Co, Fe, Ca, B and Mo) and five doses of each biofertilizer [(0.0, 0.6, 1.2, 1.8 and 2.4) L·plant–1] was adopted. Results of boron, copper, iron, manganese, zinc and sodium foliar contents were submitted to variance analysis, the Tukey test and regression analysis. Results and discussion. The results indicate that enriched biofertilizer promoted the statistically highest foliar contents of all elements. The biofertilizer doses applied had different effects on foliar contents of the elements studied. Conclusion. Micronutrient and sodium foliar contents of yellow passion fruit were affected by both the type and doses of biofertilizers. Simple biofertilizer promoted optimum supplies of boron and iron, while enriched biofertilizer supplied boron, iron, manganese and zinc.

Introduction. Research on the mineral nutrition of Barbados cherry is scarce. Leaf sampling techniques for this crop are unknown. Leaf analysis, associated with the determination of the nutrient availability in the soil, can provide reliable orientation for the establishment of fertilizer programs. For a correct interpretation of the nutritional status, it is important (1) to evaluate the seasonal variation of nutrient contents in the leaves, (2) to determine the appropriate time for leaf sampling and analysis, and (3) to indicate the best part of the plant for determination of the nutritional status. These subjects were the three objectives of this study. Materials and methods. The experiment was conducted from March 1997 to February 1998 in Visconde do Rio Branco, Minas Gerais, Brazil. The dynamics of the elements N, P, K, Ca, Mg, S, Fe, Cu, Zn and Mn were studied in leaves at the apical, median and basal positions of branches located in the upper, median and lower portions of the plant canopy. Results. The minimum variation in the foliar contents occurred at the medium third of the branches located in the upper portion of the canopy. So, these parts are the most appropriate for leaf sampling. Moreover, December was characterized as the appropriate time for leaf sampling. Conclusion. The leaf sampling techniques developed will allow better study of the mineral nutrition of M. emarginata in order to establish reliable fertilizer programs and to improve the yields of this fruit tree.