984 resultados para Levantamentos do solo
Resumo:
Os levantamentos epidemiológicos são importantes para o conhecimento da prevalência e tipologia das doenças bucais, podendo-se a partir dos dados coletados, planejar, executar e avaliar ações de saúde. É necessário, no entanto, que haja rigor metodológico que garanta reprodutibilidade, validade e confiabilidade, e que haja uniformidade de procedimentos para permitir comparações nacionais e internacionais. A iniciativa da Organização Mundial da Saúde (OMS) na assessoria à realização de levantamentos tem se mostrado extremamente útil, estimulando o estabelecimento de padrões de procedimentos que podem ser utilizados em todos os países. em 1991 foi publicada a edição em português da terceira edição do Oral Health Surveys - basic methods, de 1987, um manual que objetiva fornecer instruções para a realização de levantamentos epidemiológicos e tal publicação passou a servir de base a estudos realizados em diversos locais do Brasil e do mundo. O objetivo deste trabalho, é analisar criticamente a metodologia para Levantamento Epidemiológico em Saúde Bucal da OMS, na tentativa de contribuir para o aperfeiçoamento da mesma. de acordo com a presente análise, foram encontrados pontos relevantes para consideração, referentes à amostragem, à calibração dos examinadores e aos critérios para a avaliação de saúde bucal e necessidades de tratamento. Concluiu-se, em nível de recomendação, que, devido ao caráter dinâmico do conhecimento científico e, levando-se em consideração as diferenças regionais com relação ao padrão de desenvolvimento das doenças bucais, as propostas de padronização de levantamentos devem ser periodicamente revisadas. É provável, ainda, que outros pontos importantes não tenham sido detectados nesta análise, tornando-se premente ampliar esta discussão para toda a comunidade odontológica.
Resumo:
Com o objetivo de avaliar a influência da relação P:Mg na fertilidade do solo, no estado nutricional e na produção de matéria seca da alfafa, foi realizado um experimento em vasos com Latossolo Vermelho Amarelo distrófico, segundo delineamento inteiramente casualizado, em esquema de parcelas subdivididas, com três repetições. Os tratamentos foram constituídos de combinações de P (doses: 0, 100, 200 e 400 mg kg-1, fonte: superfosfato triplo) e Mg (doses: 0, 100 e 200 mg kg-1, fonte: cloreto de magnésio), nas proporções de 0, 0,5, 1, 2 e 4. No período experimental, foram realizados três cortes, com intervalo de 30 dias (subparcelas). Os resultados demonstraram que o incremento da relação P:Mg e das doses de P e de Mg aumenta a produção de matéria seca. O teor de P e as combinações de P:Mg no tecido vegetal apresentaram estreita relação com a proporção desses nutrientes no solo. A relação 2:1 acarretou maior teor de clorofila e N na matéria seca, enquanto altas quantidades de P no solo diminuíram a absorção de K.
Resumo:
In this work it was demanded to verify the zinc critical levels in soybean plants cultivated in a Dark-Red Latosol. So the experiment was carried out in vases with 4 liters of soil, which has received five doses of Zn (0, 1.0, 2.0, 3.0 and 4.0 ppm) in three correction levels. It was verified that the critical levels of the nutrient in plant (for 90% from highest production) was between 36 and 53 ppm to the dry matter yield and grains in treatments with correction.
Resumo:
O objetivo do experimento foi verificar o efeito do nitrogénio no solo, parcelado de diferentes formas e aplicado durante o período de "verão", combinado com pulverização foliar de ureia e/ou ácido giberélico, sobre a produção e qualidade de Setaria anceps Stapf cv. Kazungula. O nitrogênio (60 kg/ha/ano) foi aplicado segundo quatro formas de parcelamento: Testemunha (sem nitrogênio), N20M40 (20 kg/ha de N em novembro + 40 kg/ha de N em março), N30M30 (30 kg/ha de N em novembro + 30 kg/ha de N em março), F20M40 (20 kg/ha de N em fevereiro + 40 kg/ha de N em março). No início do período de "inverno" foram aplicados os quatro tipos de pulverizações foliares: Testemunha (sem ácido giberélico ou uréia), uréia a 2%, ácido giberélico a 50 ppm e uréia a 2% + ácido giberélico a 50 ppm. Os resultados revelaram que o parcelamento do nitrogénio no solo não influiu no aumento da produção de matéria seca do capim setária no período de "verão", apesar de proporcionar um incremento da mesma no corte de "inverno". Observou-se, ainda, uma boa distribuição da produção de matéria seca entre "verão" e "inverno", apresentando essa última estação 34,52% da produção total anual, em média. Os diferentes tipos de pulverização não influíram significativamente sobre a produção de matéria seca e a composição química bromatológica da forrageira no período de "inverno".
Resumo:
Potassium deficiency in soybeans has spread iii São Paulo State, Brazil, as a consequence of soil K reserve depletion. Exchangeable and nonexchangeable K dynamics in soil were investigated in order to understand the reserve exaustion and its significance to soybean nutrition. Soybean was grown in 8 1 pots with five soils differing in K and clay contents, in presence or absence of K fertilization. Soil samples were taken at 20 days interval and soybean was harvest at R6. Exchangeable (H2SO4 0,05 N) and nonexchangeable K (boiling HNO3) were estimated in soil sample. Two of the soils were very poor in exchangeable K, and even so there was no response in dry matter due to K fertilization. In spite of some differences in K contents in some of the soybeans parts, generally K absorption was not affected by K fertilization, except in grains. Potassium acumulation in soybean plants were affected by soils, but the response was not closely related to exchangeable K in soil. The main K source to the plants was the HNO3 extrated K, showing that this form is not at all nonexchangeable. After the period of maximum plant demand there was a sharp increase in extractable K in soil showing a tendency to a natural equilibrium.
Resumo:
Two experiments were carried out in pots with a Dusky Latossol showing a 15% base saturation. In the first experiment dolomitic limestone was applied to reach 45, 60, 75 and 90% of base saturation. In the second, MnSO4 was applied in rates of 30, 60, 90 and 120 ppm,and base saturation was raised to 70%.Soybean plants cv. IAC-9 were grown up to R6, when dry matter production and manganese accumulation were evaluated. Soybean responded to liming up to 60% base saturation, as Mn availability and evantualy Mn absorption were decreased to non-toxic levels. Mn applied to a reclamed soil up to 120 ppm was not enough to cause toxicity to soybean cv IAC-9. All of the chemical extractors (Ammonium Acetate, DTA, Mehlich and H2SO4) showed modification in Mn availabity in soil but were not definitely related to Mn absorption and dry matter production.
Resumo:
The aim of this study was to try the forecast of corn (Zea mays L.) sowing dates, the understanding of the quantitative effect of water deficits on that crop and crop yield decrease on a basis of a climatic model of water deficit forecast. This model was applied at Cambara (lat. 23 degrees 00'S, long. 50 circle 02'WGr, altitude 450 m), PR, Brazil. The model estimates yield decrease, in relation to potential values, as a function of the sowing dates which determine flowering and grain filling dates, highly critical times in relation to water deficit. The estimates were done from expected values of water deficit, at the 80% probability level and accumulated degrees-days, using several climatological data. Results show that the first ten days of November are the best corn sowing date under dry or irrigated conditions. Under these same conditions, the worst time showed to be August. Estimates of total needs of supplementar irrigation get values of 126 e 226 mm, respectively to the corn sowed at the first ten days of November and August.
Resumo:
The objective of this study was to analyze, using the geoestatistic and a system of classification fuzzy, the fertility of an experimental area with base in chemical attributes of the soil and its relationship with the productivity of the conilon coffee. The study was accomplished in the experimental farm of the INCAPER - ES. The soil samples were collected in the depth of 0 - 0.2 m, being analyzed the attributes: matches, potassium, calcium and magnesium, aluminum, sum of bases, cation exchange capacity (pH 7), and saturation percentage. The data were submitted to a descriptive, exploratory, and geostatistical analysis. A system of fuzzy classification was applied using the attributes described to infer about the fertility of the soil and its relationship with the productivity of the culture. The fertility possibility presented positive spatial relationship with the productivity of the culture, with higher values of this where the possibility of fertile soil is superior.
Resumo:
The microorganisms are essential components in the maintenance of the biological and physicochemical balance of the soil. They exert important function including the degradation of residues of plants and animals and the release of nutrients in the alimentary chain. This work had as objective to compare the microbiota of a soil under bush covering (SMS) and other cropped with vegetables (SHC), suppressive or not it Rhizoctonia solani. Total microbial community DNA was extracted of soils, amplification for PCR of the genes 16S rDNA, inserted into pGEM (R)-T cloning vector and sequencing of the genes of the ribosomal RNA. The analysis of the results demonstrated that this methodology was efficient for evaluation of bacteria in ground. In the bush soil suppressive the microorganisms more found belonged to the phyla of the Acidobacterias, Verrucomicrobia and Actinobacterias and in the soil cultivated with vegetables the biggest frequency was of organisms pertaining to the phyla of the Proteobacterias, Firmicutes and Bacteroidetes.
Resumo:
A harmful and limiting factor regarding culture productivity is soil compaction, a parameter that can be quantified by the resistance of the soil to penetration and highly influenced by water content. These variables present spatial and temporary variability, characteristics which can be determined by the geostatistical technique. In the light of the above, the present work had as its objective the study of spatial variability of soil resistance to penetration (RP) and water content in the soil (U) in soy culture. The RP values at depths of 0,00-0,10; 0,11-0,20 and 0,21-0,30 m varied from 2,9 to 4,28 MPa and are considered harmful to the root development of legumes, although they have not influenced soy productivity which was 3887 kg ha(-1). The medium water content of the soil was between 0,210 and 0,213 kg kg(-1) for the three depths studied. The resistance of the soil to penetration, expressed through semivariograms, presented spatial dependence at all depths, being adjusted to the spherical model at depths of 0,00-0,10m and exponential at depths of 0,110,20 and 0,21-0,30 m. The spatial variability for all studied layers presented a range of about 20m. The water content in the soil did not present spatial dependence for the depths, presenting randomized distribution.
Resumo:
No-tillage system is an efficient technique in control of soil erosion, when compared with conventional tillage, however, some studies indicate higher compaction under no-tillage, mainly in the surface layer. Strategies that increase the organic matter content, as crop rotation and organic fertilization, can be used to solve the soil compaction. The aim of this study was to evaluate the effect of soil managements (crop succession and crop rotation) and fertilization (organic, mineral and organic-mineral) in the physical properties of the soil, under no-tillage system, from 2006 to 2008. The evaluations were carried out in February 2007, after the summer corn harvest, and in September 2008, after the winter corn harvest. Crop rotation decreased the soil density and soil resistance to penetration and increased the macroporosity and total porosity. The use of organic sources of fertilization did not affect any of the physical attributes of soil. The yield of summer corn was highest in succession crop and mineral fertilization, however, in the winter, there was no difference between the soil managements and among the fertilizations.
Resumo:
The evaluation of micronutrient availability in agricultural soil treated with sewage sludge was developed in Field with maize cultivation on a Dystrophic Red Latosol. The experiment used a randomized complete block design, with the treatments in a split-plot scheme, in time, with six doses of sewage sludge (main-plot treatment) in relation to the five sampling periods for the soil (subplot treatment), with four replications. The sewage sludge was applied in the superficial layer (0-20 cm). The micronutrients Fe, Cu, Mn and Zn were extracted from the soils using a DTPA (diethylenetriaminepentaacetic acid) solution. The same micronutrients were analyzed in the plant tissue after the nitric-perchloric decomposition of the maize samples by spectrometric atomic absorption. The results showed an increasing amount of Fe, Mn, Zn, Cu, Cation Exchange Capacity (CEC) and a decreasing pH in the soil. The increasing doses of sewage sludge increased the Fe, Mn, Cu and Zn availability in the soil solution, and the uptake amount by maize plants were always greater than the control values.
Resumo:
In this work the distribution was evaluated "in situ" of phosphorus (P), organic matter (MO), potassium (K), calcium (Ca), magnesium (Mg), cation exchange capacity (CEC), aluminum (Al), sum of bases (S), base saturation (V) and pH of a soil cultivated with soybean and irrigated with swine wastewater in the 0, 25, 50 and 75% levels. The factorial scheme was constituted by the 20, 40 and 60 cm soil depths and four wastewater levels with five repetitions. The results showed that significant difference occurred only for P, K and CEC in the soil profile. However, in all parameters, the 60 cm soil depth showed that the concentrations levels are similar to before the aplication of treatments.
Resumo:
The objective of this work was to evaluate the effect of nitrogen sources and rates on maize nutrition and grain yield under no-tillage system in sandy soil. The experiment was conducted in a Typic Quartzipsamment, in the city of Cassilandia, State of Mato Grosso do Sul, Brazil. A completely randomized block design was used in a factorial array 3x4 with four replicates. Treatments consisted of three sources [urea, extruded urea with starch (Starea), and ammonium sulfonitrate with nitrification inhibitor of 3,4-dimethylpyrazole-phosphate (Entec (R) 26)] and four rates (0, 45, 90 and 180 kg ha(-1)) of nitrogen, applied in side-dressing when the plants presented four and six expanded leaves. The nitrogen source affected N, K, and S concentration in the leaf, but did not interfere in the components of production and maize grain yield. Nitrogen application like ammonium sulfonitrate promoted higher concentrations of N, K and S in the maize leaf in relation to the urea, especially in the larger rates studied. Side-dressing nitrogen fertilization increased the number of ears per plant, number of grains per ear and grain yield, grown under no-tillage system in sandy soil, independent of the used source.
Resumo:
Land occupation and its use have a remarkable influence on the superficial water flow and the carrying of sediments to the riverbed and may change the quality and availability of water. The current study aimed to check the influence of the land occupation and use on the Tres Barras stream resources, in Marinopolis, SP, Brazil. To check this influence, an analysis of Pearson's correlation between the parameters of quality and availability and use of water and land was developed. The samples covered the period of January, 2006 until December, 2007. It may be concluded that areas occupied by forests and pastures (in less intensity) favoured the availability and quality of water of the watershed. The inhabited areas and those used for agriculture, and the degraded forests in general, reduced the availability and quality of water in the watershed.