Concepción Maldonado González

Improving the relationship between soil characteristics and metal bioavailability by using reactive fractions of soil parameters in calcareous soils

The contribution of the nature instead of the total content of soil parameters relevant to metal bioavailability in lettuce was tested using a series of low-polluted Mediterranean agricultural calcareous soils offering natural gradients in the content and composition of carbonate, organic, and oxide fractions. Two datasets were compared by canonical ordination based on redundancy analysis: total concentrations (TC dataset) of main soil parameters (constituents, phases, or elements) involved in metal retention and bioavailability; and chemically defined reactive fractions of these parameters (RF dataset). The metal bioavailability patterns were satisfactorily explained only when the RF dataset was used, and the results showed that the proportion of crystalline Fe oxides, dissolved organic C, diethylene-triamine-pentaacetic acid (DTPA)-extractable Cu and Zn, and a labile organic pool accounted for 76% of the variance. In addition, 2 multipollution scenarios by metal spiking were tested that showed better relationships with the RF dataset than with the TC dataset (up to 17% more) and new reactive fractions involved. For Mediterranean calcareous soils, the use of reactive pools of soil parameters rather than their total contents improved the relationships between soil constituents and metal bioavailability. Such pool determinations should be systematically included in studies dealing with bioavailability or risk assessment.

Terminología e información gramatical en textos didácticos y diccionarios

Grammatical terminology and information in teaching texts and dictionaries. This paper sets out the different approach that we believe should be taken with regard to discrepancies of approach and the disparity of grammatical terms in textbooks and in linguistic reference works, particularly when such works are designed for different compulsory courses in primary and secondary education. Based on almost thirty years of editorial experience, and using representative examples taken from dictionaries and from Latin, French, English and Spanish grammar, this paper firstly attempts to show how the level of complexity of grammatical information included in educational reference works should be inversely proportional to the level of knowledge of the language user. Secondly, we analyse how, unfortunately, it is almost general practice for editorial teams to write their materials using a theoretical approach which they do not later follow in the development of educational materials across the different courses.