Search

Sugarcane is an annual crop with a dynamic canopy that changes over time mainly because of genetic adaptation. There is uncertainty about the temporal trends of throughfall (TF) in this important commercial crop. In the present paper, we used troughs to measure TF in a third and fourth ratoon and subsequently in a fourth and fifth ratoon. Additional measurements were carried out in an adjacent riparian forest. There were no significant differences between cycles of sugarcane, growth phases and riparian forest. The TF results for ratoon crop and riparian forest in 2011/2012 were 76% and 79.5% of gross rainfall, respectively, while in 2012/2013, they were 79% and 78%, respectively. However, TF was remarkably lower in the riparian forest relative to ratoon from the second half of the culm formation and elongation phase (280 days after harvest) until harvest. Copyright © 2016 John Wiley & Sons, Ltd.

Since an understanding of how runoff is generated is of great importance to soil conservation, to water availability and to the management of a watershed, the objective of this study was to understand the generation of surface runoff in a watershed covered by sugarcane and riparian forest. Nine surface runoff plots were set up, evenly distributed on the lower, middle and upper slopes. The lower portion was covered by riparian forest. We showed that the average surface runoff coefficient along the slope in the present study was higher than in other studies under different land uses. Furthermore, the surface runoff was higher under sugarcane compared to the riparian forest, especially after sugarcane harvesting. Besides land cover, other factors such as the characteristics of rainfall events, relief and physical soil characteristics such as soil bulk density and saturated hydraulic conductivity influenced the surface runoff generation.

The carbon stable isotope ratio (δ13C) has become an important tool to determine the composition and quality of various beverages, indicating the amount of C3- and C4-sources used in brewing. Accordingly, we assessed the isotopic composition of beers produced in Brazil and abroad, in order to quantify the use of C4-sources as adjuncts. We also related the presence of such adjuncts to beer price, and compared the current results to similar studies, in order to assess any differences regarding beer composition over time. The mean δ13C value for Brazilian beers was around −22.0‰, indicating a high addition of C4-adjuncts during the brewing process. A dichotomy of beer isotopic signatures was observed: beers from large breweries had higher δ13C values (around −20.0‰) than beer from artisanal breweries (−25.0‰). Beer price per L was directly related to δ13C values in Brazil and abroad. This significant relationship, in addition to the 13C-enrichment observed in this study, may reflect a change in the Brazilian beer market, in which a greater variety of beverages are produced and marketed following traditional recipes regarding their purity.

Brazil is the largest producer of ethanol from sugarcane in the world. While the ethanol industry is economically important to Brazil for several reasons, it also has a significant impact on the environment. Here we analyze the water consumptive use in the transformation of the feedstock (sugarcane) into ethanol and the impact of industrial byproduct effluents on water resources of the state of Sao Paulo, Brazil. Our estimates indicated that in the 2007-2008 harvest, 700 million m3 was withdrawn mainly from rivers and streams by 140 mills, and of this total 440 million m3 was consumed which yielded a water use of approximately 1.53 m3 ·water·tonˉ1 sugarcane or approximately 18 L·water·L-ˉ1 ethanol. At the same time, a total of 120 million m3 of vinasse by-product was produced in the state, equivalent to an organic load of approximately 3 billion kg·BOD during the harvest season or approximately 8 million kg·BOD·dˉ1. Although the water used by sugarcane mills has decreased in recent decades, it is still possible to further decrease the amount of water used by ethanol production. This would decrease the pressure on 1st order streams of the state from which most water is withdrawn. In addition, the enormous volume of vinasse production must be reduced because it exerts constant pressure on aquatic ecosystems, soil and groundwater due to the constant increase in the potassium (K) concentration in areas where it is used as a fertilizer.

Based on the fact that streamwater quality reflects landscape conditions, the objectives of this study were: to investigate nitrogen (N), carbon (C), and major ion concentrations in six streams crossing minimally disturbed Atlantic Forest areas, with similar geomorphological characteristics; to determine N and C fluxes in one of these pristine streams (Indaia); and assess the impact of human activity on the biogeochemistry of two other streams in the same region, crossing urbanized areas. The distribution pattern of carbon and inorganic nitrogen dissolved forms, as well as the major ion and biogenic gas concentrations in the streamwater, was similar in pristine streams, indicating that the C and N dynamics were determined by influence of some factors, such as climate, atmospheric deposition, geology, soil type, and land covering, which were analogous in the forested watersheds. The urban streams were significantly different from the pristine streams, showing low dissolved oxygen concentrations, high respiration rates, and high concentrations of carbon dioxide, dissolved inorganic nitrogen, dissolved inorganic carbon, and major ion. These differences were attributed to anthropogenic impact on water quality, especially domestic sewage discharge. Additionally, in the Indaia stream, it was possible to observe the importance of rainfall over temporal dynamics of dissolved carbon forms, and also, the obtained specific flux of dissolved inorganic nitrogen was relatively elevated (approximately 11 kg ha−1 year−1). These results reveal the influence of human activity over the biogeochemistry of coastal streams and also indicate the importance N export of Atlantic Forest to the ocean.

Tendo em vista que a qualidade das águas dos rios reflete as condições das bacias de drenagem, o objetivo principal deste trabalho foi estudar a dinâmica do nitrogênio (N), do carbono (C) e dos íons maiores em seis rios que drenam áreas de preservação da Mata Atlântica, e investigar os impactos causados pela influência antrópica na biogeoquímica de dois rios que drenam também áreas de ocupação urbana consolidada. Além disso, uma vez inserido no Projeto Temático BIOTA - Gradiente Funcional, que busca compreender a composição, a estrutura e o funcionamento da Floresta Ombrófila Densa Atlântica, o presente estudo objetivou também determinar os fluxos de N e C em um dos rios estudados, contribuindo desta forma para o cálculo do balanço destes nutrientes no ecossistema em questão. Foram selecionados oito rios no município de Ubatuba-SP e realizadas as coletas mensais (set/06 a dez/07). As coletas intensivas, a cada dois dias (dez/06 a mar/08), foram realizadas apenas no rio onde foram estimados os fluxos dos nutrientes, sendo que em mar/08 foi realizada ainda neste rio a coleta diu-noturna (de hora em hora por dois dias consecutivos). As microbacias que possuem características hidrológicas, geomorfológicas e fisiográficas semelhantes apresentaram mesmo padrão de distribuição dos gases biogênicos, das formas de carbono e nitrogênio e dos íons maiores dissolvidos nas águas. Os rios que drenam áreas urbanas diferiram significativamente dos demais rios estudados, tanto em relação às variáveis relacionadas ao metabolismo aquático (apresentando menores concentrações de oxigênio dissolvido e maiores valores de pressão parcial do dióxido de carbono e das taxas respiratórias), quanto em relação às concentrações de nutrientes e íons maiores (apresentando maiores concentrações de carbono e nitrogênio inorgânico dissolvido, assim como maiores valores do somatório de cargas iônicas). Estas diferenças foram relacionadas às interferências antrópicas nestas duas microbacias, principalmente aos aportes de efluentes domésticos. Através dos resultados obtidos na coleta diu-noturna, foi constatada a importância dos eventos de chuvas intensas na dinâmica temporal das formas de carbono dissolvido, assim como de íons maiores. Além disso, foram obtidos, no estudo intensivo, fluxos relativamente elevados de carbono orgânico dissolvido (6,9 kg C ha-1 ano-1), de carbono inorgânico dissolvido (22,4 kg C ha-1 ano-1) e de nitrogênio inorgânico dissolvido (3,2 kg N ha-1 ano-1). De acordo com os resultados obtidos, concluí-se que a influência antrópica promoveu significativas alterações na biogeoquímica dos rios e que a Floresta Ombrófila Densa Atlântica apresenta expressivas perdas das formas dissolvidas de C e N, via fluxo hidrológico. Based on the fact that streams water quality reflects the conditions of the landscape, the objectives of this study were: to investigate nitrogen (N), carbon (C) and major ions dynamics in six streams covered by Atlantic Forest; and assess the impacts of the human activities over the biogeochemistry of two urban streams at same region. Since this study is part of BIOTA Thematic Project Functional Gradient, N and C fluxes were determined at one of the streams, in order to contribute with the estimation of nutrient balances for the Atlantic Forest. Eight streams were selected at Ubatuba, State of São Paulo. Water was monthly sampled from Sept-06 to Dec-07 at all streams. At one of the streams (Indaiá) water samples were taken every two days from Dec-06 to Mar-08; and also water samples were collected every hour during a 48h period at Mar-08. The pristine watersheds showed the same pattern in terms of distribution of biogenic gases, C, N and major ions concentrations in the streamwater. The urban streams were significantly different from the pristine streams regarding to: (i) aquatic metabolism - low dissolved oxygen concentrations, high carbon dioxide concentrations and high respiration rates; and (ii) nutrient and major ions concentrations - high dissolved inorganic nitrogen and carbon concentrations as well as high ionic concentrations. These differences were attributed to anthropogenic impacts at water quality, especially domestic sewage discharge. Besides, it was found relatively high fluxes of dissolved organic carbon (6.9 kg C ha-1 yr-1), dissolved inorganic carbon (22.4 kg C ha-1 yr-1), and dissolved inorganic nitrogen (3.2 kg N ha-1yr-1). Through the 48h sampling at Indaiá stream it was possible to observe the importance of intense rainfalls events over temporal dynamics of dissolved carbon forms and major ions concentrations. These results reveal the influence of human activities over the biogeochemistry of costal streams and also show the importance of Atlantic Forest hydrological fluxes of dissolved C and N to the ocean.