Crescimento De Cana-de-açúcar Sob Aplicação De Biofertilizante Da Bovinocultura E Ureia

Effluents from intensive cattle breeding and treated with anaerobic reactors are highly relevant for agricultural reuse. Current paper assesses the growth of sugarcane cultivars SP 803280 and RB 867515 for 220 days. Doses 0, 16, 48, 64, 80 and 96 kg ha-1 N were applied derived from biofertilizing sources produced by cattle-breeding waste water and urea. Experimental design comprised randomized blocks with 96 splits and four replications. The cultivars fertilized with biofertilizers caused growth similar to those fertilized with urea. Doses 64, 80 and 96 kg ha-1 had the best efficiency in growth. Since average height of 3 m was obtained for cultures at the end of the experiment, urea may be replaced by biofertilizers.9497398

Implications of CO2 pooling on δ13C of ecosystem respiration and leaves in Amazonian forest, Biogeoscience

The carbon isotope of a leaf (d13Cleaf) is generally more negative in riparian zones than in areas with low soil moisture content or rainfall input. In Central Amazonia, the small-scale topography is composed of plateaus and valleys, with plateaus generally having a lower soil moisture status than the valley edges in the dry season. Yet in the dry season, the nocturnal accumulation of CO2 is higher in the valleys than on the plateaus. Samples of sunlit leaves and atmospheric air were collected along a topographical gradient in the dry season to test whether the d13Cleaf of sunlit leaves and the carbon isotope ratio of ecosystem respired CO2 (d13CReco) may be more negative in the valley than those on the plateau. The d13Cleaf was significantly more negative in the valley than on the plateau. Factors considered to be driving the observed variability in d13Cleaf were: leaf nitrogen concentration, leaf mass per unit area (LMA), soil moisture availability, more negative carbon isotope ratio of atmospheric CO2 (d13Ca) in the valleys during daytime hours, and leaf discrimination (¿leaf). The observed pattern of d13Cleaf might suggest that water-use efficiency (WUE) is higher on the plateaus than in the valleys. However, there was no full supporting evidence for this because it remains unclear how much of the difference in d13Cleaf was driven by physiology or &delta13Ca. The d13CReco was more negative in the valleys than on the plateaus on some nights, whereas in others it was not. It is likely that lateral drainage of CO2 enriched in 13C from upslope areas might have happened when the nights were less stable. Biotic factors such as soil CO2 efflux (Rsoil) and the responses of plants to environmental variables such as vapor pressure deficit (D) may also play a role. The preferential pooling of CO2 in the low-lying areas of this landscape may confound the interpretation of d13Cleaf and d13CReco

Land System Science In Latin America: Challenges And Perspectives

This article reviews the current status, trends and challenges of land system science in Latin America. We highlight the advances in the conceptualization, analysis and monitoring of land systems. These advances shift from a focus on the relationships between forests and other land uses to include a greater diversity of land cover and land-use types and the processes and interactions that link them. We then provide a biome-level typology of social-ecological land systems (SELS) as an approach to help connect local-level realities to regional processes and we discuss how this approach can help to design more socially inclusive land systems. We also discuss the increased role of distant socio-economic and ecological interactions that connect these SELS to global processes. Combined, these insights support a research agenda for land system science in the region that can develop more accurate and integrative monitoring of land change and their social and ecological consequences, better understand different stakeholder perspectives within a context of livelihood diversification, and encourage institutional feedbacks to govern land systems influenced by distant drivers. © 201726-27374

Can land use changes alter carbon, nitrogen and major ion transport in subtropical brazilian streams? Modificações no uso da terra podem alterar o transporte fluvial de carbono, nitrogênio e íons maiores?

Several studies in tropical watersheds have evaluated the impact of urbanization and agricultural practices on water quality. In Brazil, savannas (known regionally as Cerrados) represent 23% of the country's surface, representing an important share to the national primary growth product, especially due to intense agriculture. The purpose of this study is to present a comprehensive evaluation, on a yearly basis, of carbon, nitrogen and major ion fluxes in streams crossing areas under different land use (natural vegetation, sugar cane and eucalyptus) in a savanna region of SE Brazil. Eucalyptus and sugar cane alter the transport of the investigated elements in small watersheds. The highest concentration of all parameters (abiotic parameters, ions, dissolved organic carbon DOC - and dissolved inorganic carbon - DIC) were found in Sugar Cane Watersheds (SCW). The observed concentrations of major cations in Eucalyptus Watersheds (EW) (Mg, Ca, K, Na), as well as DIN and DOC, were found frequently to be intermediate values between those of Savanna Watersheds (SW) and SCW, suggesting a moderate impact of eucalyptus plantations on the streamwater. Same trends were found in relation to ion and nutrient fluxes, where the higher values corresponded to SCW. It is suggested that sugar cane plantations might be playing an important role in altering the chemistry of water bodies.<br>Diversos estudos têm sido desenvolvidos em bacias de drenagem tropicais no intuito de avaliar o impacto da urbanização e das práticas agrícolas na qualidade dos corpos d'água. No Brasil, as savanas (conhecidas regionalmente como Cerrado) representam 23% do território brasileiro, sendo uma região importante no crescimento nacional, especialmente devido às intensas atividades agrícolas. A finalidade deste trabalho é apresentar uma avaliação dos fluxos de carbono, nitrogênio e principais íons em córregos com diferentes usos do solo (vegetação, cana de açúcar e eucalipto) em uma região de Cerrado, SE Brasil. A cana de açúcar e o eucalipto alteram o transporte dos elementos investigados nessas pequenas bacias de drenagem. As concentrações mais elevadas de todos os parâmetros analisados (parâmetros abióticos, íons, carbono orgânico dissolvido e carbono inorgânico dissolvido) foram encontradas na bacia de cana de açúcar (SCW). As concentrações observadas para os cátions na bacia do eucalipto (EW) (Mg, Ca, K, Na), assim como Carbono Inorgânico Dissolvido (CID) e Carbono Orgânico Dissolvido (COD), apresentaram valores intermediários entre as bacias do Cerrado e da cana de açúcar, sugerindo um impacto moderado dessa plantação aos corpos d'água. Mesma tendência foi observada para os fluxos de íons e nutrientes, sendo, novamente, os maiores valores encontrados na bacia de cana-de-açúcar. Os autores sugerem que o cultivo da cana de açúcar representa um importante fator na modificação da química de pequenas bacias de drenagem