Atrazine sorption in soil treated with biochar.

Biochar has been used worldwide as soil amendment. Due to the high sorption capacity of organic compounds by charcoal in general, the use of biochar can change the soil sorptive properties, that could result in a environmental protective strategy in one hand and/or in need of higher pesticides doses in another hand. However no data in the literature is available about the long term effect of biochar application in the sorptive properties of the soil, even studies about the sorptive properties of soil treated with biochar are scarce, the few available papers are with pure biochar. This unprecedented work, evaluating the sorption of atrazine in a clayed soil treated with biochar, under experimental field conditions, evaluated the sorption isotherms one and three years after the single biochar application (16 Mg ha-1 of biochar). One year after the biochar application the Kf was two times higher for the biochar amended soil than for the control one (without biochar). This effect decreases after three years from the application, but it is even significantly higher (50% higher) than the control treatment.

Desafíos contemporáneos para el socialismo en Cuba (A propósito de las reformas políticoeconómicas en la fase actual de la revolución)

This essay analyzes on the origin and impact of the amendment process currently undertaken by the Cuban government authorities considering it as the result of --what I call-- super structural imbalance. Such imbalance is caused by the application of the System for Management and Planning of the Economy. To our judgment, the process of amendment both structurally and super structurally conforms the new phase in the construction of the Socialism in the island from a coherent point of view to what it has been until now as a political constant of the revolution: the vindication of the human being as the promoter of its historical reality.

Impacts of trace element pollution on sewage sludge and soil-plant systems: developing remediation techniques and assessing plant uptake prevention measures

Trace Elements (TEs) pollution is a significant environmental concern due to its toxic effects on human and ecosystem health and its potential to bioaccumulate in the food chain and to threaten species survival, leading to a decline in biodiversity. Urban areas, industrial and mining activities, agricultural practices, all contribute to the release of TEs into the environment posing a significant risk to human health and ecosystems. Several techniques have been developed to control TEs into the environment. This work presents the findings of three-year PhD program that focused on research on TEs pollution. The study discusses three fundamental aspects related to this topic from the perspective of sustainable development, environmental and human health. (1) High levels of TEs contamination prevent the use of sewage sludge (SS) as a fertilizer in agriculture, despite its potential as a soil amendment. Developing effective techniques to manage TEs contamination in SS is critical to ensure its safe use in agriculture and promote resource efficiency through sludge reuse. Another purpose of the study was to evaluate different strategies to limit the TEs uptake by horticultural crops (specifically, Cucumis Melo L.). This study addressed the effect of seasonality, Trichoderma inoculation and clinoptilolite application on chromium (Cr), copper (Cu) and lead (Pb) content of early- and late-ripening cultivars of Cucumis Melo L.. Finally, the accumulation of copper and the effect of its bioavailable fraction on bacterial and fungal communities in the rhizosphere soil of two vineyards, featuring two different varieties of Vitis vinifera grown for varying lengths of time, were evaluated.