We assessed substrate‐induced respiration and soil chemical properties in order to study the influence of charcoal, nitrogen and phosphorus fertilisation on two different perennial crops in a confounded factorial design on a highly weathered Amazonian upland soil. Each plantation tested three different factors in three different levels making up 27 (33) treatment combinations. Whereas the banana plantation received mineral fertilisation in addition to charcoal applications (3rd factor), the guarana (Paullinia cupana) plantation was fertilised organically using chicken manure and bone meal as the corresponding factors. Charcoal increased pH, total nitrogen, availability of sodium, zinc, manganese, copper and soil humidity, and decreased aluminium availability and acidity in the mineral‐fertilised plantation only. This caused a significant increase in basal respiration and microbial efficiency in terms of carbon dioxide release per microbial carbon in the soil. The microbial biomass, efficiency and population growth after substrate addition was significantly increased with increasing levels of organic fertiliser amendments. We conclude that charcoal is a valuable component especially in inorganic‐fertilised agricultural systems. Copyright © 2008 John Wiley & Sons, Ltd

RESUMOSulfato de amônio (SA) e uréia (U) marcados com 15 N foram aplicados na cultura do milho, em sucessão à aveia preta (Avena strigosa Schieb.), no sistema plantio direto, 43 dias antes e 31 dias depois da semeadura, na dose de 80 kg ha -1 de N, incorporados a 5-7 cm de profundidade, em sulcos espaçados de 0,8 m, nas entrelinhas do milho. O objetivo foi quantificar o N dos fertilizantes imobilizado no solo ( 15 N-orgânico), no sulco de adubação, e o N-recuperado na planta nos estádios de 5-6 folhas, 11-12 folhas, florescimento e maturação fisiológica. O delineamento experimental foi inteiramente casualizado com parcelas subdivididas e três repetições. As parcelas foram constituídas das fontes U e SA, e as subparcelas, das épocas de aplicação de N. O experimento foi realizado em Latossolo Vermelho ácrico típico fase cerrado subcadocifólio, na Fazenda Floresta do Lobo-Pinusplan, em Uberlândia (MG). Na aplicação em pré-semeadura, a máxima imobilização foi observada aos 19 dias da aplicação do SA (13,3 kg ha -1 ou 16,6 % do N-aplicado) e aos 40 dias da aplicação da U (13,7 kg ha -1

Sugarcane growing area in Brazil sharply expanded between 2000 and 2010 due to the increasing world demand for sugar and ethanol. Since this expansion of sugarcane is said to occur in areas covered by degraded pastures, it is likely not threatening the environment or food production. In order to verify this assumption, we investigate at farm and field levels which types of land use sugarcane cropping replaced between 2005 and 2010 and the reasons for farmers shifting or not shifting to sugarcane, as a case study in two counties in the state of Goiás. Within the studied period, sugarcane cropping expansion was related to large farms, lower risk perceived by farmers, and higher profitability compared with soybean and beef cattle-raising. For smallholders, particularly dairy farmers, the need to comply with the set-aside rules under Brazilian Forest Code (Código Florestal Brasileiro) made a shift to sugarcane less attractive, as it would have forced them to reduce farm cultivable area, with loss of incomes. From 30,408 ha under sugarcane surveyed, 45.7% had used to be pastures, 31% had previously been pastures rotated with soybean and maize, and 23.3% had been cropped exclusively with soybean or maize.

The propagation of the guarana plants using seeds is nowadays not recommended because the high variability in the productivity and susceptibility to diseases. The cuttings propagation of a select guarana plant clones is recommended for Amazonas State. The objective of this study was to evaluate the survival rate of cuttings of twelve clones of guaraná in three substrates with three replicates. The evaluated clones were: BRS 300, BRS 871, BRS 372, BRS 648, BRS 189, BRS 505, BRS 610, BRS 612, BRS 850, BRS 882, BRS 608, BRS 611. The growing media tested were 50% of soil + 50% of chicken manure (v/v); 50% chicken manure + 50% sieved powdered charcoal (v/v) and a comercial growing media for vegetables (Plantmax ® ). The comercial growing media and the misture of chicken manure + sieved powdered charcoal substrate produced the higher cuttings survival rate. The clone BRS Amazonas showed the highest percentage of survival (88.2%) and clone BRS 372 the lowest (15%).