Wood sawdust is a solid residue, generated in the timber industry, which is of no profitable use and can cause serious environmental problems if disposed inadequately. The aim of this study was to use the eucalyptus sawdust in the preparation of activated carbons AC) and test them as adsorbents of methylene blue (MB) and phenol, representative pollutants from aqueous effluents of various industries. The eucalyptus sawdust was characterized by instrumental analysis such as elementary analysis (CHNS-O), thermogravimetric analysis (TGA), infrared spectroscopy (FTIR) and scanning electron microscopy (SEM , respectively, for MB and phenol).Index terms: Agro-industrial residues, adsorbents, pollutants. RESUMOA serragem é um resíduo sólido, gerado na indústria madeireira, que não tem uso rentável e pode causar sérios problemas ambientais quando disposta inadequadamente. Neste estudo, objetivou-se utilizar a serragem de eucalipto na preparação de carvões ativados (AC) e testá-los como adsorventes do corante azul de metileno (MB) e fenol; moléculas que representam poluentes de efluentes industriais. A serragem de eucalipto foi caracterizada por análises instrumentais, tais como: análise elementar (CHNS-O), análise termogravimétrica (TGA), espectroscopia na região do infravermelho (FTIR) e microscopia eletrônica de varredura (SEM). Os carvões ativados foram preparados por ativação física com dióxido de carbono AC_CO 2 , (10º Cmin , respectivamente, para MB e fenol). Termos para indexação:Resíduos agroindustriais, adsorventes, poluentes.

Droughts associated with climate change alter ecosystem functions, especially in systems characterized by low biodiversity, such as agricultural fields. Management strategies aimed at buffering climate change effects include the enhancement of intraspecific crop diversity as well as the diversity of beneficial interactions with soil biota, such as arbuscular mycorrhizal fungi (AMF). However, little is known about reciprocal relations of crop and AMF diversity under drought conditions. To explore the interactive effects of plant genotype richness and AMF richness on plant yield under ambient and drought conditions, we established fully crossed diversity gradients in experimental microcosms. We expected highest crop yield and drought tolerance at both high barley and AMF diversity. While barley richness and AMF richness altered the performance of both barley and AMF, they did not mitigate detrimental drought effects on the plant and AMF. Root biomass increased with mycorrhiza colonization rate at high AMF richness and low barley richness. AMF performance increased under higher richness of both barley and AMF. Our findings indicate that antagonistic interactions between barley and AMF may occur under drought conditions, particularly so at higher AMF richness. These results suggest that unexpected alterations of plant-soil biotic interactions could occur under climate change.

Intensive land use of the Brazilian Atlantic Forest accelerated with the rise of sugar cane plantations in the northeastern part of Brazil. Consequently, many ecosystems were destroyed, including riparian forests. The number of studies of riparian restoration has increased but comparative studies on the belowground effects of common reforestation strategies are rare. Here, we compared soil microbial properties among four different land use types: native rainforest, sugar cane plantation, single species reforestation, and mixed species reforestation, each replicated at two spatially independent sites. Soil samples were taken in 2013 and 2014, that is 2 and 3 years after reforestation, respectively. In both years, land use types had a significant effect on basal respiration, microbial biomass, and specific respiration (whereas specific respiration was marginally affected in 2014). In 2013, basal respiration in sugar cane plantations was significantly lower (−65%) when compared to native forests. In 2014, basal respiration (+60%) and soil microbial biomass (+90%) were significantly higher in mixed species reforestation compared to sugar cane, whereas single species reforestation had comparable values as in sugar cane plantations. Our results indicate that soil microbial biomass and activity respond rapidly to land use change when mixed species reforestation is used. Thus, using mixed species reforestation may enhance the provisioning of ecosystem services already in the short term.

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Palavras-chave: Áreas degradadas; Desenvolvimento; Sementes. IntroduçãoAs atividades de recuperação de áreas degradadas vêm buscando cada vez mais, modelos que aproximem a nova cobertura vegetal de uma sucessão ecológica com estabilidade dinâmica. Isto não se deve só ao ajuste ecológico destes novos povoamentos, mas também à redução no custo e à maior chance de sucesso (RODRIGUES, 2006). A interação dos conhecimentos teóricos básicos, informações sobre a área e tecnologia disponível são os fatores que vão determinar qual o modelo mais adequado para cada situação (KAGEYAMA;GANDARA, 2004).