The addition of organic residues to agricultural soils has been used as a practical alternative to improve crop quality and health. The objective of this work was to evaluate maize physiological and nutritional responses to the application of compost and biochar combined with urea (N) and N-(n-butyl) thiophosphoric triamide (NBPT). The experiment was performed in plastic pots with 3 kg of soil under greenhouse conditions for 30 days. The compost and biochar were applied at the rate of 0.3 ton ha-1, using an amount of nutrient (nitrogen, phosphorus and potassium) demanded by crop growth. The physiological responses of maize were monitored by measuring the plant height, stalk diameter, leaf chlorophyll content, shoot dry weight and root dry weight. The nutritional responses of maize were assessed by using the nutrient concentration and the total nutrient assimilation by the plants. The results showed that the addition of compost or biochar did not alter the maize physiological response compared to the addition of mineral fertilizer used under the same conditions. However, a difference occurred in the maize nutritional responses to the compost and biochar amendments combined with urea and NBPT. The greatest N concentration in maize was observed in the treatment consisting of biochar combined with urea + NBPT. All the treatments in which compost or biochar was applied in combination with urea and NBPT presented greater total N assimilation compared to the treatment with conventional fertilization. The results of this survey showed that the combination of urea and NBPT improved the nitrogen-use efficiency of maize.

Land use systems have a great impact on soil function and microbial diversity in tropical soils. Our study aimed to evaluate soil biochemical indicators and community composition and to assess the relationship between soil biochemical and microbial indicators and bacterial diversity of three agroecosystems (pine forest, soya and sugarcane) and native Cerrado forest in the Brazilian savanna. Soil biochemical indicators (soil organic matter and enzymes) and high-throughput sequencing of 16S rDNA were performed in two topsoil depths (0-5 cm and 5-10 cm). Soil microbial and enzyme activity showed that agricultural soil usage has a negative impact on soil function compared to native and pine forests. Results also revealed higher enzyme activities in 0-5 cm depth compared to 5-10 cm depth, but enzymatic activities depend on land use systems. Soil bacterial community was affected by land use systems and depth, revealing changes in structure and abundance of bacterial composition. Alphadiversity indexes were higher in the agricultural systems than in the forests, however they showed a signifi cant negative correlation with most of the studied soil microbial and biochemical indicators. Our research had brought new relevant information about the relationship between the soil biochemical indicators and the bacterial diversity in the Brazilian Cerrado.

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Este artigo apresenta e discute o projeto de extensão desenvolvido pelo grupo PET/ BIOLOGIA - UFU, intitulado "A Riqueza do Cerradoâ€?, o qual fez parte de um projeto maior, denominado "Frutificarâ€?. O objetivo foi proporcionar aos participantes conhecimentos científicos a respeito do Bioma Cerrado, com o intuito de familiarizá-los ao ambiente em que estão inseridos. O projeto foi realizado na ONG Ação Moradia no bairro Morumbi, Uberlândia-MG, de maio a setembro de 2007, com jovens de idade entre 12 e 16 anos que trabalham com mudas de Cerrado na ONG. A extensão realizada possibilitou aos participantes a assimilação de aspectos referentes ao Bioma Cerrado e também uma maior conscientização a respeito da preservação do Cerrado.

Ao meu amor Bruno, por ser meu eterno companheiro, vivendo ao meu lado todos os momentos alegres ou tristes, com carinho, paciência e dedicação, me ensinando todos os dias o verdadeiro significado da palavra AMOR. À minha Mãe, por ser essa Guerreira que sempre lutou para fazer o melhor por nós, e por me educar, auxiliar nos estudos e, acima de tudo, por me ensinar os maiores e verdadeiros valores da vida. À minha família, Darc, Dani, Tiago, Leandro e João Gabriel por acreditarem em mim desde o início, e por me apoiarem em todas as decisões e por dividirem comigo cada momento especial da minha vida. A memória de minha querida vovó Dirce, minha professora e mestre de vida, por todos os seus ensinamentos, carinho, dedicação e amor incondicional. Mesmo distante esta é mais uma conquista e um sonho que realizamos juntas! Vocês são tudo de mais importante em minha vida. Amo Vocês! Palavras-chave: carbono da biomassa, respiração basal, atividade enzimática do solo, hidrólise de diacetato fluoresceína (FDA), β-glicosidase, urease, fosfatase ácida, desidrogenase, 16S rDNA, pirosquenciamento, fertilizante orgânico e organomineral, nitrogênio, Cerrado.