Propriedades físico-hídricas, compactação do solo, desenvolvimento radicular e produtividade da soja em diferentes manejos de solo

A cultura da soja (Glycine Max L.) faz parte da rotação de culturas praticadas pelos irrigantes do sudoeste paulista, os quais praticam o plantio direto como forma de uso sustentável do solo. O objetivo do trabalho foi avaliar o efeito dessa prática conservacionista sobre as propriedades físico-hídricas do solo, sobre sua compactação, sobre o desenvolvimento radicular e sobre a produtividade da cultura da soja, comparativamente com o preparo convencional. O experimento foi conduzido na Fazenda Buriti-Mirim, município de Angatuba, SP (23º30'13" S, 48º35'37" W; 640m), durante o segundo semestre de 2003, utilizando uma área de Argissolo Acinzentado irrigada por pivô central, dividida em dois tipos de manejo do solo preparo convencional e plantio direto. Embora no plantio direto tenha-se encontrado maior densidade do solo, menor quantidade de água disponível e menor resistência do solo à penetração, os dois manejos não diferiram quanto ao desenvolvimento radicular e a produtividade da soja.

Resíduo sólido orgânico urbano e níveis de irrigação no cultivo de crambe

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Propriedades espectrais uniformes para operadores de Schrödinger com potenciais Sturmianos

Pós-graduação em Matematica Aplicada e Computacional - FCT

Matéria orgânica do solo em rotações de culturas sob sistema semeadura direta

Pós-graduação em Agronomia (Agricultura) - FCA

Processo de preparação de zirconia dopada e não dopada pela rota sol-gel usando nitrato de zirconila como material de partida

Processo de Preparação de Zirconia Dopada e não Dopada pela Rota Sol-Gel Usando Nitrato de Zirconila como Material de Partida compreendendo as etapas de preparação de uma solução de nitratos de zirconila e outros nitratos metálicos em solução aquosa com composto orgânico de etanol metanol ou acetona, através do controle de molaridade. Embora não limitantes, valores ideais para molaridade das soluções são: entre 1,00 e 0,29 para obtenção de pó entre 0,29 e 0,18 para obtenção de superfície recoberta e entre 0,18 e 0,13 para obtenção de filmes finos. Manter a solução a 0°C para formação de filmes finos por imersão do substrato ou monocristal com velocidade constante ("dip-coating") ou por rotação a velocidade constante ("spinning"), ou para recobrimento de superfícies metálicas através de imersões sucessivas do substrato metálico a velocidade constante ("dip-coating"). Elevar a solução a 50°C para hidrolização e formação de um gel em forma de pó, secagem de pó ou liofilização, calcinação e moagem dos aglomerados.

Energetic efficiency of an agricultural tractor in function of tire inflation pressure

The tire inflation pressure, among other factors, determines the efficiency in which a tractor can exert traction. It was studied the effect of using two tire inflation pressures, 110.4 kPa in the front and rear wheels, 124.2 kPa in the front wheel and 138 kPa in the rear wheels, the energetic efficiency of an agricultural tractor of 147 kW of engine power, in the displacement speed of 6.0 km.h-1, on track with firm surface, with the tractor engine speed of 2000 rpm. For each condition of the tire pressure, the tested tractor was subjected to constant forces in the drawbar of 45 kN and 50 kN, covering 30 meters. It was used a randomized complete block with a 2x2 factorial arrangement (tire pressure and drawbar power) with four replications, totaling 16 experimental units. Data were subjected to analysis of variance, using the Tukey test at 5% probability for comparison averages. The lowest hourly and specific fuel consumption, the lowest slippage of the wheelsets and the highest efficiency in the drawbar was obtained with the tire inflation pressure of 110.4 kPa in the front and rear tires of the tractor, highlighting that lower pressures improve energetic and operational performance of the tractor.

Assessment of first molars sagittal and rotational position in Class II, division 1 malocclusion

OBJECTIVE: This study assessed the anterior-posterior positioning of the upper and lower first molars, and the degree of rotation of the upper first molars in individuals with Class II, division 1, malocclusion. METHODS: Asymmetry I, an accurate device, was used to assess sixty sets of dental casts from 27 females and 33 males, aged between 12 and 21 years old, with bilateral Class II, division 1. The sagittal position of the molars was determined by positioning the casts onto the device, considering the midpalatal suture as a symmetry reference, and then measuring the distance between the mesial marginal ridge of the most distal molar and the mesial marginal ridge of its counterpart. With regard to the degree of rotation of the upper molar, the distance between landmarks on the mesial marginal ridge was measured. Chi-square test with a 5% significance level was used to verify the variation in molars position. Student's t test at 5% significance was used for statistical analysis. RESULTS: A great number of lower molars mesially positioned was registered, and the comparison between the right and left sides also demonstrated a higher number of mesially positioned molars on the right side of both arches. The average rotation of the molars was found to be 0.76 mm and 0.93 mm for the right and left sides, respectively. CONCLUSION: No statistically significant difference was detected between the mean values of molars mesialization regardless of the side and arch. Molars rotation, measured in millimeters, represented ¼ of Class II.

Chemical and biological properties of phosphorus-fertilized soil under legume and grass cover (Cerrado region, Brazil)

The use of cover crops has been suggested as an effective method to maintain and/or increase the organic matter content, while maintaining and/or enhancing the soil physical, chemical and biological properties. The fertility of Cerrado soils is low and, consequently, phosphorus levels as well. Phosphorus is required at every metabolic stage of the plant, as it plays a role in the processes of protein and energy synthesis and influences the photosynthetic process. This study evaluated the influence of cover crops and phosphorus rates on soil chemical and biological properties after two consecutive years of common bean. The study analyzed an Oxisol in Selvíria (Mato Grosso do Sul, Brazil), in a randomized block, split plot design, in a total of 24 treatments with three replications. The plot treatments consisted of cover crops (millet, pigeon pea, crotalaria, velvet bean, millet + pigeon pea, millet + crotalaria, and millet + velvet bean) and one plot was left fallow. The subplots were represented by phosphorus rates applied as monoammonium phosphate (0, 60 and 90 kg ha-1 P2O5). In August 2011, the soil chemical properties were evaluated (pH, organic matter, phosphorus, potential acidity, cation exchange capacity, and base saturation) as well as biological variables (carbon of released CO2, microbial carbon, metabolic quotient and microbial quotient). After two years of cover crops in rotation with common bean, the cover crop biomass had not altered the soil chemical properties and barely influenced the microbial activity. The biomass production of millet and crotalaria (monoculture or intercropped) was highest. The biological variables were sensitive and responded to increasing phosphorus rates with increases in microbial carbon and reduction of the metabolic quotient.

Arbuscular mycorrhizal fungal communities and soil aggregation as affected by cultivation of various crops during the sugarcane fallow period

Management systems involving crop rotation, ground cover species and reduced soil tillage can improve the soil physical and biological properties and reduce degradation. The primary purpose of this study was to assess the effect of various crops grown during the sugarcane fallow period on the production of glomalin and arbuscular mycorrhizal fungi in two Latosols, as well as their influence on soil aggregation. The experiment was conducted on an eutroferric Red Latosol with high-clay texture (680 g clay kg-1) and an acric Red Latosol with clayey texture (440 g kg-1 clay) in Jaboticabal (São Paulo State, Brazil). A randomized block design involving five blocks and four crops [soybean (S), soybean/fallow/soybean (SFS), soybean/millet/soybean (SMS) and soybean/sunn hemp/soybean (SHS)] was used to this end. Soil samples for analysis were collected in June 2011. No significant differences in total glomalin production were detected between the soils after the different crops. However, total external mycelium length was greater in the soils under SMS and SHS. Also, there were differences in easily extractable glomalin, total glomalin and aggregate stability, which were all greater in the eutroferric Red Latosol than in the acric Red Latosol. None of the cover crops planted in the fallow period of sugarcane improved aggregate stability in either Latosol.

Ruzigrass affecting soil-phosphorus availability

The objective of this work was to evaluate the effectiveness of ruzigrass (Urochloaruziziensis) in enhancing soil-P availability in areas fertilized with soluble or reactive rock phosphates. The area had been cropped for five years under no-till, in a system involving soybean, triticale/black-oat, and pearl millet. Previously to the five-year cultivation period, corrective phosphorus fertilization was applied once on soil surface, at 0.0 and 80 kg ha-1 P2O5, as triple superphosphate or Arad rock phosphate. After this five-year period, plots received the same corrective P fertilization as before and ruzigrass was introduced to the cropping system in the stead of the other cover crops. Soil samples were taken (0-10 cm) after ruzigrass cultivation and subjected to soil-P fractionation. Soybean was grown thereafter without P application to seed furrow. Phosphorus availability in plots with ruzigrass was compared to the ones with spontaneous vegetation for two years. Ruzigrass cultivation increased inorganic (resin-extracted) and organic (NaHCO3) soil P, as well as P concentration in soybean leaves, regardless of the P source. However, soybean yield did not increase significantly due to ruzigrass introduction to the cropping system. Soil-P availability did not differ between soluble and reactive P sources. Ruzigrass increases soil-P availability, especially where corrective P fertilization is performed.

Soil nitrogen dynamics after Brachiaria desiccation

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

Corn productivity in function of surface application of lime in differents management systems and cultural preparation

The evaluation of technologies employed at the agricultural production system such as crop rotation and soil preparation, both associated with crop-livestock integration, is crucial. Therefore, the aim of the present study was to evaluate the incorporation of lime for three no-tillage systems and cultural managements in system of crop-livestock integration, with emphasis on corn grain yield. The experiment was conducted from January 2003 to April 2005 at Selvíria city, MS, in Dystroferric Red Latosol, clay texture. The experimental design was randomized blocks with split plots consisted of three main treatments, aimed the soil physics conditioning and the incorporation of lime: PD - No-no-tillage; CM - minimum no-tillage, and PC - conventional no-tillage; and of two secondary treatments related to the management: rotation and crop succession, with four replications. Data on agronomic traits of maize were analyzed: plant height, stem diameter, height of the first spike insertion, 100 grains weight and grain yield. The results showed that the maize produced under the system of crop-livestock integration is quite feasible, showing that grain yields are comparable to averages in the region and the different soil physical conditioning and incorporation of lime did not influence the corn yield as well as the cultural managements, rotation and succession, did not affect the maize crop behavior after two years of cultivation.

Características físicas, reológicas e sensorial de produtos extrusados de misturas de farinha de maracujá e fécula de mandioca

This research had as objective to evaluate the effect of extrusion temperature and screw speed on physical and rheological properties, as well as, the sensory acceptance of cassava and passion fruit snacks produced in single-screw extruder. A central composite design with 11 treatments was used, considering as dependent variables: expansion index (EI), specific volume (SV), water solubility index (WSI), water absorption index (WAI), color (L*, a*, b*) and pasting properties (RVA). The products were flavored and analyzed for global acceptance. The results showed significant effects of temperature and screw speed on the dependent variables. The chocolate flavored snacks obtained good acceptance.

Cassava and turmeric flour blends as new raw materials to extruded snacks

Short cooking time and ability to blend varieties of food ingredients have made extrusion cooking a medium for low-cost and nutritionally improved food products. The effect of moisture, extrusion temperature and amount of turmeric flour mixed with cassava flour on physical characteristic of puffed snacks was evaluated in this work. Extrusion process was carried out using a single-screw extruder in a factorial central composite design with four factors. Results showed effect of extrusion parameters on dependents variables. High expansion, low browning, low water solubility index, intermediate water absorption index and high crispness desirable characteristics to puffed snacks are obtained in conditions of 12% moisture, 5% turmeric flour, 105º C of temperature and 250 rpm of screw speed. These paper point to the potential still unexplored of the use of flours of cassava and turmeric as raw materials in the development of extruded puffed snacks.

Desenvolvimento de um biorreator rotativo para produção de enzimas celulolíticas por fermentação em estado sólido

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)