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Ecofisiología Vegetal y Producción de Cultivos / Plant Ecophysiology and Crop ProductionIntegrated system for recommending fertilization rates in pineapple (Ananas comosus (L.) Merr.) crop Sistema integrado para recomendar dosis de fertilización en el cultivo de la piña (Ananas comosus (L.) Merr.) AbstractIn recent years much attention has focused on the impacts of agriculture on climate change, due to this stage specialists in plant nutrition and soil fertility have achieved the task of generating adequate fertilization doses for pineapple to reduce effects on environment. A methodology for Integrated System for Recommending Fertilizer Dose (ISRFD) was used. As a result, seven Thiessen polygons of the average annual rainfall, where rainfall ranged from 1640 to 2841 mm was correlated. Therefore, three major soil groups were defined and classified as subunit level. Likewise, eight doses of fertilizers were generated as follows: N, P 2 O 5 and K 2 O, with a fertilizer dose, a map is generated according to the cultivar: 230-138-300 for Creole pineapple in Acrisol Cutanic (Chromic, Ferric); 460-161-480 for Cayenne and MD2 in Acrisol Cutanic (Endoclayic, Ferric); 345-161-450 for Cayenne and MD2, for Creole in Acrisol Cutanic (Endoclayic, Hyperdystric, Ferric); 391-161-450 for Cayenne and MD2 in Acrisol Umbric Cutanic (Endoclayic, Hyperdystric) and Acrisol Umbric Cutanic (Endoclayic, Hyperdystric, Ferric); 207-138-300 for Creole in Acrisol Umbric Cutanic (Endoclayic, Hyperdystric); 253-138-300 for Creole in Acrisol Umbric Cutanic (Endoclayic,Hyperdystric, Ferric); 253-138-360 for Creole in Acrisol Umbric Gleyic (Hyperdystric, Ferric); and 391-161-360 in Cambisol Endogleyic (Clayic, Eutric). These fertilizer doses were supplemented with micronutrients to obtain the expected results.

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In the present work, we report a methodology for the rapid detection of soil pollution by hydrocarbons that is based on direct coupling of a headspace sampler with a mass spectrometer. With no prior treatment, the samples are subjected to the headspace generation process and the volatiles generated are introduced directly into the mass spectrometer, thereby obtaining a fingerprint of the sample analyzed. The mass spectrum corresponding to the mass/charge ratios (m/z) ranging between 49 and 160 atomic mass units (amu) contains the information related to the composition of the headspace and is used as the analytical signal for the characterization of the samples. Chemometric treatments, such as hierarchical cluster analysis (HCA), linear discriminant analysis (LDA), and soft independent modeling class analogy (SIMCA) were used to characterize the different types of samples analyzed. The main advantage of the proposed methodology is that no prior chromatographic separation and no sample manipulation are required. The method is rapid, simple, and in view of the results, highly suitable for detecting pollution in soils polluted by hydrocarbons.

En el Panel Intergubernamental de las Naciones Unidas sobre el Cambio Climático, se ha indicado que el secuestro de carbono por las plantas es una alternativa de bajo costo para reducir el contenido de dióxido de carbono (CO2) atmosférico. Por ello, el manejo forestal y de humedales representa una oportunidad para el almacenamiento de carbono. En el caso de los suelos orgánicos de manglares, los promedios de descomposición son bajos y su potencial de almacenamiento de carbono es alto, por lo que pueden ser una alternativa para el secuestro de carbono. En esta investigación se cuantificó la reserva de carbono en suelos orgánicos con vegetación de mangle (Rhizophora mangle L. y Laguncularia racemosa (L.) Gaertn) en la parte oeste del estado de Tabasco, México, encontrándose que el contenido de carbono fluctúa entre 47 kg C m-2 y 82 kg C m-2, lo cual refleja el gran potencial que tienen.