Características biológicas do solo indicadoras de qualidade após dois anos de aplicação de biossólido industrial e cultivo de milho

A utilização agrícola de biossólidos tem sido muito incentivada, mas, como esses resíduos apresentam composição química variada, o valor agronômico e os efeitos sobre características indicadoras de qualidade do solo precisam ser avaliados caso a caso, a fim de estabelecer normas de segurança para uso desses materiais. Neste trabalho foram avaliadas características biológicas, após a aplicação, por dois anos consecutivos, de doses crescentes (0, 6, 12, 18 e 24 t ha-1 base seca) de um biossólido gerado por uma indústria de fibras e resinas PET e da adubação mineral completa no cultivo de milho, em um Cambissolo distrófico, comparados aos de uma área adjacente, sob Brachiaria sp. e sem cultivo nos últimos 10 anos, usada como referência. Os valores de C e N da biomassa microbiana, a respiração basal e as atividades das enzimas urease e beta-glicosidase e da hidrólise do diacetato de fluoresceína (FDA) aumentaram, enquanto a atividade da fosfatase ácida diminuiu com a elevação das doses de biossólido, porém estas não tiveram efeito sobre o quociente metabólico (qCO2). A diminuição da atividade da fosfatase se deveu ao aumento da disponibilidade de P no solo, não caracterizando efeito adverso da aplicação do biossólido. Com aplicação de 12 t ha-1 de biossólido (recomendação agronômica), a respiração e a hidrólise da FDA foram maiores e a atividade da fosfatase foi menor que a obtida no solo com adubação mineral, mas as demais características avaliadas não diferiram entre estes tratamentos. A colonização micorrízica de Brachiaria sp. não diferiu entre plantas de crescimento espontâneo nas parcelas anteriormente cultivadas com milho e aquelas da área adjacente. Apesar do menor número de esporos, verificou-se enriquecimento de espécies de fungos micorrízicos arbusculares (FMAs) nas parcelas cultivadas. O carbono orgânico (Corg) e a biomassa microbiana apresentaram alta correlação com os demais parâmetros avaliados, indicando que as alterações na quantidade e qualidade da matéria orgânica, promovidas pela aplicação do biossólido, refletiram na dinâmica da microbiota e influenciaram positivamente os parâmetros biológicos de qualidade do solo.

Degradação de pastagens na Região Amazônica: propriedades físicas do solo e crescimento de raízes

O objetivo deste trabalho foi avaliar: (i) a relação entre a degradação de pastagens de colonião manejadas com queima, e as modificações nas propriedades físicas e morfológicas de um Argissolo Vermelho-Amarelo da Amazônia; (ii) o crescimento radicular de pastagens com diferentes níveis de degradação; (iii) o potencial de recuperação de pastagens degradadas de colonião com a introdução de andropógon. Numa propriedade rural da Região de Marabá, PA, foram estudados quatro tipos de pastagem: pastagem produtiva de colonião (Panicum maximum Jacq.); pastagem de colonião em declínio produtivo; pastagem de colonião degradada (capoeira); pastagem de colonião degradada e recuperada com andropógon (Andropogon gayanus Kunth). Como referência das propriedades do solo antes do desmatamento, estudou-se, também, uma reserva de mata nativa. A queima das pastagens foi prática usual, e apesar disso, estas não foram adubadas. A degradação da pastagem diminuiu a cobertura do solo e o deixou exposto à chuva e ao pisoteio do gado, o que resultou em aumento da densidade do solo na camada superficial e diminuição do grau de floculação da argila e da porosidade total. A diminuição da produção da parte aérea na pastagem degradada foi acompanhada de diminuição do número de raízes no perfil do solo, e da concentração do sistema radicular próximo à superfície. O andropógon demonstrou bom potencial para recuperação das áreas de pastagens degradadas, na Região Amazônica.

Efeito do processamento UAT (Ultra Alta Temperatura) sobre as características físico-químicas do leite

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Atributos físicos de um Latossolo Vermelho correlacionados linear e espacialmente com a consorciação de guandu com milheto

O sistema cultivo mínimo, por possibilitar pouca movimentação de solo, menor número de operações agrícolas sem incorporação dos resíduos vegetais, apresenta vantagens em razão do menor custo de preparo e da redução das perdas de solo e água. No ano agrícola de 2006/2007, na Fazenda de Ensino e Pesquisa da Faculdade de Engenharia de Ilha Solteira, SP, Brasil - FEIS/UNESP, situada nas condições do Cerrado Brasileiro, objetivou-se analisar a produtividade de massa de matéria seca da consorciação de forragem (guandu+milheto) (MSF), em função de atributos físicos do solo, tais como resistência à penetração (RP), umidade gravimétrica (UG), umidade volumétrica (UV) e densidade do solo (DS) nas profundidades de 0,0-0,10 m; 0,10-0,20 m e 0,20-0,30 m. Para tanto, foi instalado um ensaio, contendo 117 pontos amostrais, em um Latossolo Vermelho distroférrico, sob pivô central, numa área experimental de 1600 m² sob cultivo mínimo. A análise estatística constou de análise descritiva inicial dos atributos e análise das correlações lineares simples entre eles, e, finalmente, de análise geoestatística. do ponto de vista da correlação espacial, o atributo que mais bem explica a produtividade de massa de matéria seca da consorciação é a densidade do solo na camada de 0,20-0,30 m, com uma correlação inversa, indicando que as espécies se desenvolvem bem em solos adensados.

Caracterização do óleo das sementes de Pachira aquatica Aublet para aproveitamento alimentar

Os frutos de Pachira aquatica Aublet apresentam sementes comestíveis com características organolépticas muito apreciadas pelas populações amazônicas, sendo pouco utilizados em outras regiões. Este trabalho teve como objetivo caracterizar as sementes quanto à composição centesimal e determinar as características físico-químicas e perfil de ácidos graxos. A determinação da composição centesimal das sementes (teores de umidade, lipídios, proteínas, cinzas e carboidratos) e análises do óleo extraído das mesmas (ácidos graxos livres, índices de peróxido, iodo, refração, saponificação, ponto de fusão e perfil de ácidos graxos) foram realizadas seguindo metodologia oficial. O teor de óleo nas sementes 38,39% demonstrou que estas têm potencial para aproveitamento industrial. Das características físico-químicas analisadas, o óleo extraído das sementes apresentou 39,2% de ácidos graxos livres (expresso em % ácido oleico), índice de iodo de 27,4 g I2.100 g-1, índice de saponificação de 208,0 mg.KOH g-1, índice de refração (40 °C) de 1,4569 e ponto de fusão de 41,9 °C. Quanto à composição de ácidos graxos do óleo predominaram os ácidos palmítico (44,93%), oleico (39,27%) e linoleico (11,35%). Tal fato favorece o uso deste óleo como matéria-prima para as indústrias alimentícia, farmacêutica e de cosméticos.

Liming in the transition to no-till under a wheat-soybean rotation

Soil and subsoil aluminium toxicity has been one of the main limiting factors for soybean and wheat yields in tropical soils. Usually liming is the most effective way to deal with soil acidity and Al toxicity, but in no-till systems the soil is not disturbed making it impossible to incorporate lime in the arable layer, and lime has been usually applied on the soil surface. In this paper soybean and wheat responses to lime applied on the soil surface and/or incorporated in the soil arable layer were evaluated during the transition from conventional tillage to a no-till system. The experiment was conducted for 3 years in Parana, Brazil, using a wheat-soybean rotation. Lime rates ranging from 0.0 to 9.0 t ha(-1) were incorporated down to 20 cm and 4.5 t ha(-1) were spread or not on the soil surface. Soil samples were taken down to 60 cm, 39 months after the first lime application. Soil chemical characteristics were affected by lime application down to 60 cm deep in the profile. Soybean responded to lime irrespective of application method, but the highest accumulated yield was obtained when lime was incorporated into the arable layer. For wheat, the more sensitive the cultivar, the greater was the response to lime. During the introduction of a no-till system, lime must be incorporated into the arable layer when the wheat cultivar is Al-sensitive. (C) 2007 Elsevier B.V. All rights reserved.

Distribuição de poros e densidade de latossolos submetidos a diferentes sistemas de uso e manejo

Man cultivates the soil for centuries, but the intensive business and use of the soils under Cerrado vegetation for agricultural production grew out of the seventies. The objective of this study was to evaluate soil physical characteristics as a function of sampling time and the soil uses in a Cerrado area in Uberlandia City - MG, Brazil. The managements were adopted: degraded pasture (M-1), conventional tillage (M-2), minimum tillage (M-3), tillage absence (M-4), no-tillage (NT) for three years (M-5); NT for nine years (M-6), NT for three years after Pinus (M-7), PD for one year after Pinus (M-8) and Pinus forest (M-9) with 25 years old. The evaluations were conducted in 2002/03 growing season, in two areas. The soils were: area 1, an Oxisol (Red Latosol - LV-1, M-1 through M-5) and area 2, two Oxisols (Red Latosol and Red-Yellow Latosol - LVA and LV-2, M-6 through M-9). The physical attributes studied changed depending of the soil class, sampling time and management systems, with emphasis on the area 2 soils, which, in general, better preserved its main physical attributes. Managements with intense tillage, such as the M-2, are the most soil physically degrade, presenting mostly negative changes to soil bulk density, total porosity, microporosity and macroporosity. Since the systems which promote less tillage, in short term, to preserve desirable physical attributes. The M-9 system had the lowest attributes range, compared to the others.

Effect of calcium and magnesium silicate on the growth of the castor oil plant subjected to salinity levels

Salt stress decreases the osmotic potential of soil solution causing water stress, causing toxic effects in the plants resulting in injuries on the metabolism and nutritional disorders, thus compromising the plant growth, resulting in lower production. The calcium silicate and magnesium can perform the same function as limestone, besides providing silicon to plants, may also contribute to the resistance of plants to salt stress. Thus, the objective of this study was to evaluate the effect of calcium and magnesium silicate on the growth of the castor oil plant BRS Energia cultivated under saline conditions. This study evaluated plant height, stem diameter, number of leaves, leaf area, dry weight of shoot and root, and soil chemical characteristics. There was no interaction between factors of salinity level and of silicate level regarding the evaluated variables. There was a direct relationship between salinity levels and plant growth in height and stem diameter. The K concentration in soil were affected by salinity levels.

Incorporação de mucuna-preta e de restos culturais de milho antes da cultura do feijão (Phaseolus vugaris L.) de inverno

The experiments were conducted during two years (1990/91 and 1992/93), to study the effects of the incorporation of bengal velvetbean and of residues on the development and yield of the winter bean crops. The trial was developed in experimental field at the Faculdade de Engenharia de Ilha Solteira, UNESP, located in Selvíria, MS, Brazil, in dark red latosol covered by savanna vegetation. It was concluded that: the incorporation of residues of corn or corn + bengal velvetbean or only bengal velvetbean had no effects on soil chemical characteristics, evaluated 80 days after the residues incorporation; in yield and bean crop development, no statistical differences were observed among treatments.

Adubação verde em Citrus: Influência na porosidade e retenção de água de um latossolo vermelho-escuro do noroeste do estado de São Paulo

The objective of this research was to study the porosity, bulk density and retention of water of an Oxisol, located in the Northwestern region of Sn̄o Paulo state, Brazil. The soil was cultivated with Citrus sp., to which green manure was applied between rows for three years. Each of six species of green manure crops (Crotalaria juncea L., Mucuna deeringiana Steph. & Bart., Canavalia ensiformis L. DC., Cajanus cajan L., Lablab purpureum L. and Ricinus communis L.) were seeded for three years (1995, 1996 and 1997) between Citrus rows, plus a treatment with a mix of all six species and a control (natural regrowth af vegetation). The experimental design was a randomized complete block design, with four replications for each of the eight treatments. Water retention, microporosity, macroporosity, total porosity and bulk density were analyzed in the beginning (1995) and end (1997) of the experiment, at three depth ranges (0-0.10; 0.10-0.20 and 0.20-0.40m). We concluded that there were statistically significant differences for bulk density, macroporosity, total porosity and retention of water among the different soil depth ranges; there were no significant differences among treatments though.

Influence of carrageenan and total solids content on the rheological properties of lactic beverage made with yogurt and whey

The purpose of this work was to study the influence of carrageenan level (X 1) and total solids content of yogurt/whey mixture (X 2) on starter culture fermentation time, physicochetnical properties (pH, fat and total solids contents) and rheological characteristics of lactic beverages using response surface methodology. The physicochemical characteristics of the lactic beverages were similar to those of commercial products. All beverages showed non-Newtonian fluid behavior with thixotropy and yield stress. The total solids content of the lactic beverages had a greater influence on the rheological behavior of these products than the carrageenan level. Wide ranges of consistency measurements were observed by varying the stabilizer level and total solids content.

Dinâmica de cátions na raiz e folhas de berinjela cultivada sobre doses crescentes de potássio oriundas de duas fontes

This study was conducted at the Department of Plant Production, Sector Horticulture, UNESP - Botucatu, SP, Brazil, in order to assess the dynamics of cationic nutrients in roots and leaves and effects on dry matter production of roots and shoots in eggplant grown on conditions of increasing doses of potassium from two distinct sources (KCl and K 2SO 4). The experiment was arranged in randomized blocks in factorial 2 × 4 (two sources of potassium, KCl and K 2SO 4 and four doses of each source equivalent, 250, 500, 750 and 1000 kg ha -1 K 2O) comprising eight treatments with three replicates. For the experiment we used Oxisol medium texture (615 g of sand, silt 45 g and 340 g clay per kg soil). The characteristics evaluated were: soil electrical conductivity, mass of shoot and root material, content and ratio of K +, Ca 2+ and Mg 2+ in roots and leaves of eggplant. We conclude that excessive doses of sources of K 2O affected the production of dry matter of roots and shoots, as well as electrical conductivity. The accumulation and the relationship of Ca2+/K+, Mg 2+/K + were affected by increased K + concentration; K 2SO 4 was the fertilizer that was less damaging.

Maçã 'Royal Gala' revestida com quitosana estocada à temperatura ambiente

The aim of this work was to evaluate apples covered with chitosan during storage at ambient temperature. 'Royal Gala' apples were covered with chitosan (MRQ), immersed in acetic acid solution (MB) or did not receive any treatment (MC) and subsequently analyzed physicochemical, sensorial andinstrumentally, as well as for rotten occurrence, at zero, 7, 14, 21, 28, 35, 42 and 46 days of storage. The ratio, pH and reducing sugar contents increased while total titratable acidity, total sugars, total solids and firmness were reduced during storage. Was observed a drastically reduction of ascorbic acid and slight increase on soluble solids, except in the apples that were not pretreated (MC). Luminosity and chromaticity ratio values improved with time, with higher intensity in MRQ. Rotten occurrence was not expressive. The acceptance of appearance, color, global impression, aroma and flavor decreased with time, and appearance and texture were considered the most important sensory attributes for apples. The use of chitosan delayed ripening, reduced losses in firmness and presented a more intense bright, extending shelf life period up to seven days.

Shelf Life of Fresh and Pasteurized Organic Passion Fruit (Passiflora Edulis F. Flavicarpa Deg.) Pulp

The shelf life of the organic passion fruit pulp, both fresh and pasteurized at 70C and 90C and stored under refrigeration, was evaluated. The heat treatment did not affect the sensory and physicochemical characteristics of the pasteurized pulps when compared with the fresh pulp, except for the ascorbic acid content. The pulps were also microbiologically safe. The pulps pasteurized at 70 and 90C were suitable for consumption for a minimum shelf-life period of 207 days of storage under refrigeration and for the fresh pulp it was attributed a shelf-life period of 60 to 90 days. The pulp pasteurized at 70C showed higher acceptance scores for all the attributes and purchase intention scores, suggesting a more stable behavior and higher sensory quality. Practical Applications: This work intended to evaluate the influence of the minimum pasteurization on the sensory acceptance and microbiological and physicochemical characteristics of the organic passion fruit pulp stored under refrigeration, with the aim to identify the shelf life. Heat treatment is one of the processes used for food preservation. Lower pasteurization temperature than that used by the Brazilian industries and storage under refrigeration showed to be appropriate for passion fruit pulp quality. In this way, the microbiological, physicochemical and sensory features of passion fruit were preserved. This work can be used as a reference for passion fruit pasteurization, which is able to increase the shelf life of this fruit while preserving its desirable original features. Journal Compilation © 2012 Wiley Periodicals, Inc.

The assessment of the quality of sugar using electronic tongue and machine learning algorithms

The correct classification of sugar according to its physico-chemical characteristics directly influences the value of the product and its acceptance by the market. This study shows that using an electronic tongue system along with established techniques of supervised learning leads to the correct classification of sugar samples according to their qualities. In this paper, we offer two new real, public and non-encoded sugar datasets whose attributes were automatically collected using an electronic tongue, with and without pH controlling. Moreover, we compare the performance achieved by several established machine learning methods. Our experiments were diligently designed to ensure statistically sound results and they indicate that k-nearest neighbors method outperforms other evaluated classifiers and, hence, it can be used as a good baseline for further comparison. © 2012 IEEE.