Carbon footprint estimation for tillage operations

As a larger use of agricultural machinery, the measurement of carbon emission is highly important. Quantification of the carbon footprint is important for the identification of more sustainable and environmentally friendly practices. Information about input energy (fuel energy) used by some tillage techniques was collected and converted into carbon. In order to use low emission tillage operations, the equivalent carbon emission factors of each tillage technique were determined. The carbon equivalents for using traditional tillage system were the highest comparing with other tillage systems (158.63 kg CE ha-1 and 55.63 kg CO2e ha-1), while No-till system which give (5.8 kg CE ha-1 and 5.45 kg CO2e ha-1). Improved conservation technology and management equipment can all help minimize the carbon footprints of farm machinery.

Rheological Properties of Clay Suspensions Treated by Hydrocyclone Process

Suspensions of bentonite clays are usually employed at industrial scale in different processes as drilling fluids as well as adsorbents for removing pollutants in muds or natural waters. For these purposes, avoiding the gravitational settling of the particles is a requirement for achieving a high efficiency and a low cost operation. Unfortunately, the clays in natural deposits are usually mixed with particles of other minerals with similar density, making difficult the separation process by usual gravitational methods. Among the most efficient and lowest cost processes, the separation by hydrocyclone is preferred because of a number of advantages at the industrial scale. In this work we verify, by different experimental methods, the efficiency of this wet separation process for removing impurities in a raw bentonite mineral, and at the same time to transform a calcium bentonite in a sodium one by dissolving sodium carbonate in the liquid phase of the hidrocyclone. Afterwards, we checked by using rheological measurements the best protocol for the preparation of the suspension. We studied the rheological behaviour of clay suspensions, with different degree of impurities removal and with different solid concentration, in order to determine the minimal conditions for obtaining bentonite suspensions that do not suffer from gravitational settling during a long period of time. For this purpose, we investigated the deformation and flow of different suspensions, under steady state and oscillatory shear, and determined when they developed a high enough yield stress and an appropriate elastic response to avoid particle settling. We explain the results in view of the energy of interaction between the different surfaces (faces, edges) of the clay platelets, which favours the formation of a soft gel in which the particles are entrapped in loose flocculi that extent along all the volume of the suspensions.This study was supported by project FIS2013-41821-R (Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica, Ministerio de Economía y Competitividad, Spain, co-funded by ERDF, European Union). Mariem Mekni Abrougui acknowledges financial support from Tunisian Goverment (fellowship program) and UE (Erasmus program) for her stays in the University of Granada

Diversity of teachers’ conceptions related to environment and human rights. A survey in 24 countries

The environmental, social and economical dimensions of ESD include human rights as equality of all the human beings independently to their gender, ethnic group, religion or sexual orientation. To analyse teachers’ conceptions on environment and on human rights, and to identify eventual links between them and with controlled parameters, a large survey has been done in 24 countries (8 749 teachers). The data are submitted to multivariate analyses. In the less developed countries, the teachers’ conceptions are more anthropocentric, less awareness of the problem of the limit of resources in our planet, and less reticent to use GMO (genetically modified organisms). These teachers are more believing in God, more practicing religion, more for “a strong central power”, “against the separation between science and religion”. The priority of ESD in these countries is poverty and development, while it is to avoid wasting and excessive consumption in the most developed countries. The teachers with the most anthropocentric conceptions more agree with these propositions: “It is for biological reasons that women more often than men take care of housekeeping” and “Ethnic groups are genetically different and that is why some are superior to others”, and more disagree with: “Homosexual couples should have the same rights as heterosexual couples”. These points illustrate that some socio-cultural traditions can differ from values of ESD (the universal human rights).CIEC – FCT Research Unit 317

Improving estimation of water soil erosion by introducing lithological formation for environmental remediation

Soil erosion is a serious and complex environmental problem worldwide, especially in the centre west of Tunisia. Whereas the construction of hill reservoirs is part of the soil and water conservation strategy, many of these have a siltation problem. Dhkekira is one of the smallest watersheds in central Tunisia whose most lithological formation consists of materials that are quite susceptible to water erosion. Due to the lack of low-scale lithological data, digital IR aerial photos with 2 m spatial resolution were considered. A semi-automatic classification of aerial photos, based on the image's textural indices is developed. The lithologic map extracted from aerial photos was used as input for ANSWERS-2000 water erosion model. Results obtained indicate first, with the semi-automatic classification of the mean and standard deviation of the thumbnail histograms that image output could help to give an idea about the existence of some surface lithological formation. The model applied to Dhkekira watershed showed that the spatial difference in water erosion was not caused only by land cover and slope, but also by lithological formation. The percentage of each lithological formation in sediment yield at the Dhkekira hill reservoir was estimated to be 69% sediment yield from Pleistocene and 19.7% from Lutetian-Priabonian