Carbon content and chemical attributes of Oxisol under sugarcane harvested with and without burning

O objetivo deste trabalho foi avaliar o acúmulo de carbono e os atributos químicos de um Latossolo Vermelho distrófico em sistemas de colheita da cana‑de‑açúcar com (CQ) e sem queima (SQ), em experimento de longa duração. Em 2009, após 14 anos da implantação do experimento em Pradópolis, SP, amostras de solo foram coletadas na linha de plantio, a 0,25 m da linha e na entrelinha, nas profundidades de 0–0,05, 0,05–0,1, 0,1–0,2, 0,2–0,3 e 0,3–0,4 m. Foram determinados os teores de carbono orgânico total (COT), Ca2+, Mg2+ e K+ trocáveis, P‑resina e P‑Mehlich‑1. Em geral, no sistema SQ, os teores de COT foram superiores na linha e a 0,25 m da linha, até a profundidade de 0,3 m. Na entrelinha, o acúmulo de carbono orgânico limitou-se às duas primeiras camadas superficiais. O sistema SQ também favoreceu a capacidade de troca catiônica e os valores de Ca2+, Mg2+ e saturação por bases, independentemente de locais de amostragem, nas duas primeiras camadas superficiais. O teor de P disponível foi pouco afetado pelos sistemas de colheita, com valores maiores no CQ. A colheita sem queima favorece o acúmulo de carbono orgânico e o aumento da fertilidade do solo, exceto quanto aos teores de P disponível.The objective of this work was to evaluate the chemical attributes of a Rhodic Hapludox according to the sugarcane harvest system, with (CQ) and without burning (SQ), in long‑term experiment. In 2009, after 14 years of establishment of a field experiment in Pradópolis, SP, Brazil, soil samples were taken at the planting row, at 0.25 m from the row, and between rows, at 0–0.05, 0.05–0.1, 0.1–0.2, 0.2–0.3, and 0.3–0.4‑m depth. Total organic carbon content (TOC), exchangeable Ca2+, Mg2+ and K+, and resin and Mehlich-1 available P were determined. In general, the SQ system had higher levels of TOC in the row, and at 0.25 from the row, to a depth of 0.3 m. Between lines, the accumulation of carbon was restricted to the first two layers of the soil. SQ system also favored cation exchange capacity and the values of Ca2+, Mg2+, and base saturation, regardless of sampling location, at the first two layers. Available contents of P were little affected by harvesting systems, with higher values found in the CQ system. Harvesting without burning increases carbon accumulation and soil fertility, except for available P

Forms of phosphorus in an Oxisol cultivated with sugarcane harvested without burning

No sistema de colheita de cana-de-açúcar sem queima da palha (SQ) são depositadas, em média, 14 t ha-1 ano-1 de restos da cultura sobre as áreas de cultivo. Isso promove elevação do teor de matéria orgânica (MO) e melhoria nos atributos físicos, químicos e biológicos do solo. Contudo, os efeitos desse sistema na disponibilidade do fósforo ainda são pouco estudados. Amostras de um Latossolo foram colhidas num experimento de campo conduzido sob os sistemas SQ e com queima da cana (CQ). Foram coletadas amostras nas profundidades de 0-0,05 m, 0,05- 0,1 m, 0,1-0,2 m, 0,2-0,3 m e 0,3-0,4 m, na linha de plantio, a 25 cm da linha e na entrelinha (0,75 m da linha de plantio). Avaliaram-se: (i) variações nos atributos químicos do solo nos sistemas sob cana SQ e CQ; (ii) variações nos teores de P total, P orgânico total e as frações de P inorgânico (Pi) ligadas a ferro (Pi - Fe), a alumínio (Pi - Al), a cálcio (Pi - Ca), Pi ocluso e P - residual; e (iii) alterações nos teores das frações de Po lábil, Po biomassa, Po moderadamente lábil, Po fúlvico, Po húmico e Po não lábil. Partiu-se da hipótese de que a preservação da palha melhora os atributos químicos do solo e promove aumento da quantidade de P ligada às frações de P inorgânico (Pi) e de P orgânico (Po) mais lábeis, com maior intensidade nas posições e profundidades mais influenciadas pelo sistema radicular da planta. Houve elevação da capacidade de troca de cátions das amostras de solo coletadas no sistema SQ em todas as posições e profundidades testadas. Valores de carbono orgânico total, Ca2+, Mg2+ e V% no SQ superaram os do CQ nas camadas de 0-0,05 e 0,05-0,1 m nas posições linha, 0,25 m e entrelinha, como resposta aos efeitos positivos do acúmulo de MO proveniente da palha da cana. O teor de Pdisponível foi pouco afetado pela manutenção da palhada sobre o solo, sendo que valores mais altos foram encontrados somente na camada de 0-0,05 m nas amostras de solo coletadas no sistema CQ. Em geral, não houve diferenças nas formas de Pi entre as amostras de solo dos sistemas SQ e CQ e entre as posições e profundidades. No compartimento Po total, os resultados do sistema SQ apresentaram depleção em relação ao CQ na camada com maior densidade de raízes (0-0,05 m) e acumulação nas camadas de aplicação da adubação de plantio (0,2-0,3 e 0,3- 0,4 m). Os teores das frações de Po lábil, biomassa, moderadamente lábil, fúlvico e húmico no solo sob sistema SQ foram superiores aos do CQ, nas amostras coletadas na profundidade de 0,1- 0,2 m.In the management system of harvesting sugarcane without straw burning (SQ), 14 t ha-1 yr-1 of crop residues, on average, are deposited on the soil. So, organic matter (MO) contents increase, and physical, chemical and biological soil attributes are improved. However, the effects of phosphorus (P) availability in this system are still poorly studied. Samples of an Oxisol were collected from a field experiment conducted under SQ and under burned sugarcane (CQ) systems. Samples were collected at layers of 0-0.05 m, 0.05-0.1 m, 0.1-0.2 m, 0.2-0.3 m, and 0.3- 0.4 m in row, at 0.25 m from row and in interrow (0.75 m from the rows). We evaluated: (i) variations in soil chemical attributes in samples from both harvesting systems; (ii) changes in the contents of total P, total organic P, and inorganic P fractions (Pi) linked to iron (Pi-Fe), aluminum (Pi-Al), calcium (Pi-Ca), occluded Pi and P residual; (iii) changes in Po fractions, labile, biomass, moderately labile, fulvic, humic and non-labile. The main hypothesis is that the preservation of straw improves the chemical soil attributes and increases the amount of P bound to the most labile inorganic and organic P fractions, with greater intensity in the positions and depths most affected by sugarcane roots. Values of soil cationic exchange capacity were higher in soil samples collected in the SQ system in all positions and depths tested. The values of total organic carbon, Ca2+, Mg2+ and V% were higher in the SQ than in CQ, on the layers of 0-0.05 m and 0.05-0.1 m and on the positions of row and 0.25 m, in response to the positive effects of OM from the straw. Contents of available phosphorus were slightly affected by the maintenance of straw on the soil. Higher P values were found in samples collected in the upper layer (0-0.05 m) under CQ than under SQ harvesting system. In general, there were no differences between the values of total P and Pi fractions in soil samples from both systems. In the Po total compartment, the samples from SQ system showed depletion in relation to the CQ on the layer with the highest density of roots (0-0.05 m) and accumulation on the layers of application of fertilizer (0.2-0.3 and 0.3-0.4 m). The values of labile Po fractions (biomass, moderately labile, fulvic and humic acids) were higher in soil samples under SQ than under CQ systems in the samples collected at 0.1-0.2 m-layer

Conteúdo de carbono e atributos químicos de Latossolo sob cana-de-açúcar colhida com e sem queima

O objetivo deste trabalho foi avaliar o acúmulo de carbono e os atributos químicos de um Latossolo Vermelho distrófico em sistemas de colheita da cana-de-açúcar com (CQ) e sem queima (SQ), em experimento de longa duração. Em 2009, após 14 anos da implantação do experimento em Pradópolis, SP, amostras de solo foram coletadas na linha de plantio, a 0,25 m da linha e na entrelinha, nas profundidades de 0-0,05, 0,05-0,1, 0,1-0,2, 0,2-0,3 e 0,3-0,4 m. Foram determinados os teores de carbono orgânico total (COT), Ca2+, Mg2+ e K+ trocáveis, P-resina e P-Mehlich-1. Em geral, no sistema SQ, os teores de COT foram superiores na linha e a 0,25 m da linha, até a profundidade de 0,3 m. Na entrelinha, o acúmulo de carbono orgânico limitou-se às duas primeiras camadas superficiais. O sistema SQ também favoreceu a capacidade de troca catiônica e os valores de Ca2+, Mg2+ e saturação por bases, independentemente de locais de amostragem, nas duas primeiras camadas superficiais. O teor de P disponível foi pouco afetado pelos sistemas de colheita, com valores maiores no CQ. A colheita sem queima favorece o acúmulo de carbono orgânico e o aumento da fertilidade do solo, exceto quanto aos teores de P disponível

Sequential extraction of phosphorus in an Oxisol amended with biosolids in a long-term field experiment in Brazil

The continued growth of large cities is producing increasing volumes of urban sewage sludge. Disposing of this waste without damaging the environment requires careful management. The application of large quantities of biosolids (treated sewage sludge) to agricultural lands for many years may result in the excessive accumulation of nutrients like phosphorus (P) and thereby raise risks of eutrophication in nearby water bodies. We evaluated the fractionation of P in samples of an Oxisol collected as part of a field experiment in which biosolids were added at three rates to a maize (Zea mays L) plantation over four consecutive years. The biosolids treatments were equivalent to one, two and four times the recommended N rate for maize crops. In a fourth treatment, mineral fertilizer was applied at the rate recommended for maize. Inorganic P forms were extracted with ammonium chloride to remove soluble and loosely bound P; P bound to aluminum oxide (P-Al) was extracted with ammonium fluoride; P bound to iron oxide (P-Fe) was extracted with sodium hydroxide; and P bound to calcium (P-Ca) was extracted with sulfuric acid. Organic P was calculated as the difference between total P and inorganic P. The predominant fraction of P was P-Fe, followed by P-Al and P-Ca. P fractions were positively correlated to the amounts of P applied, except for P-Ca. The low values of P-Ca were due to the advanced weathering processes to which the Oxisol have been subjected, under which forms of P-Ca are converted to P-Fe and P-Al. The fertilization with P via biosolids increased P availability for maize plants even when a large portion of P was converted to more stable forms. Phosphorus content in maize leaves and grains was positively correlated with P fractions in soils. From these results it can be concluded that the application of biosolids in highly weathered tropical clayey soils for many years, even above the recommended rate based on N requirements for maize, tend to be less potentially hazardous to the environment than in less weathered sandy soils because the non-readily P fractions are predominant after the addition of biosolids. (C) 2012 Elsevier B.V. All rights reserved

CULTIVAR RELEASE-BRS Cometa: a carioca common bean cultivar with erect growth habit

BRS Cometa was developed by Embrapa Rice and Beans and registered by the Ministério da Agricultura,Pecuária e Abastecimento (MAPA) for the states of Santa Catarina, São Paulo, Tocantins, Goiás and the Federal District ofBrazil in view of its erect growth habit, earliness, good lodging resistance and resistance to Colletotrichum lindemuthianumand to bean common mosaic virus

Antioxidant Action and In Vivo Anti-Inflammatory and Antinociceptive Activities of Myrciaria floribunda Fruit Peels: Possible Involvement of Opioidergic System

This work evaluated the antioxidant properties and in vivo antinociceptive and anti-inflammatory effects of extracts obtained from fruit peels of Myrciaria floribunda (H. West ex Willd.) O. Berg (Myrtaceae). This plant is popularly known in Brazil as Cambuí or camboim. Different extracts were submitted to comparative analysis to determine the content of selected phytochemical classes (levels of total phenols, flavonoids, and monomeric anthocyanins) and the in vitro antioxidant potentials. The extract with higher potential was selected for in vivo evaluation of its antinociceptive and anti-inflammatory action. Finally, the chemical characterization of this extract was performed by high-performance liquid chromatography (HPLC). MfAE (extract obtained using acetone as solvent) showed the higher levels of phenols (296 mg GAE/g) and anthocyanins contents (35.65 mg Cy-3-glcE/g) that were associated with higher antioxidant activity. MfAE also exhibited in vivo anti-inflammatory and analgesic propertiers. This fraction inhibited the inflammatory and neurogenic phases of pain, and this effect was reversed by naloxone (suggesting the involvement of opioidergic system). MfAE reduced the abdominal contortions induced by acetic acid. The HPLC analysis revealed the presence of gallic acid (and its derivatives) and ellagic acid. Taken together, these data support the use of M. floribunda fruit peels for development of functional foods and nutraceutics