Effect of swine residue rates on corn, common bean, soybean and wheat yield

Swine residue (SR) applied as nutrient source of crops such as corn, bean, soybean and wheat, besides representing an environmental-friendly way of disposing of organic waste resulting from swine production, may significantly increase grain yields, replacing mineral fertilizer. The objective was to evaluate the effect of SR rates on corn, common bean, soybean and wheat yields from 2002 to 2007, in comparison with mineral fertilizer. The experiment was carried out at the Instituto Agronômico do Paraná - IAPAR, Pato Branco, PR and consisted of increasing SR rates (0, 15, 30, 45, and 60 m³ ha-1) and one treatment with mineral fertilizer (NPK 4-30-10), using 250 kg ha-1 for bean and 300 kg ha-1 for corn, soybean and wheat. Also, in the treatment with mineral fertilizer, 60, 120 and 90 kg ha-1 N was applied as topdressing to bean, corn and wheat, respectively. There were significant increases of grain yield in all evaluated years and crops with increasing SR rates, especially in the grass species under study. Also, with increasing SR rates applied every six months, K, P, Ca and Mg were accumulated in the soil and the pH increased. The application of 60 m³ ha-1 SR increased yields and exceeded the yield obtained with the recommended mineral fertilizer, indicating this amount as adequate for these crops.

Seeds with high molybdenum concentration improved growth and nitrogen acquisition of rhizobium-inoculated and nitrogen-fertilized common bean plants

Seeds of common bean (Phaseolus vulgaris) with high molybdenum (Mo) concentration can supply Mo plant demands, but to date no studies have concomitantly evaluated the effects of Mo-enriched seeds on plants inoculated with rhizobia or treated with N fertilizer. This work evaluated the effects of seed Mo on growth and N acquisition of bean plants fertilized either by symbiotic N or mineral N, by measuring the activities of nitrogenase and nitrate reductase and the contribution of biological N2 fixation at different growth stages. Seeds enriched or not with Mo were sown with two N sources (inoculated with rhizobia or fertilized with N), in pots with 10 kg of soil. In experiment 1, an additional treatment consisted of Mo-enriched seeds with Mo applied to the soil. In experiment 2, the contribution of N2 fixation was estimated by 15N isotope dilution. Common bean plants grown from seeds with high Mo concentration flowered one day earlier. Seeds with high Mo concentration increased the leaf area, shoot mass and N accumulation, with both N sources. The absence of effects of Mo application to the soil indicated that Mo contents of Mo-enriched seeds were sufficient for plant growth. Seeds enriched with Mo increased nitrogenase activity at the vegetative stage of inoculated plants, and nitrate reductase activity at late growth stages with both N sources. The contribution of N2 fixation was 17 and 61 % in plants originating from low- or high-Mo seeds, respectively. The results demonstrate the benefits of sowing Mo-enriched seeds on growth and N nutrition of bean plants inoculated with rhizobia or fertilized with mineral N fertilizer.

Nutrient extraction and exportation by common bean cultivars under different fertilization levels: I - macronutrients

The use of cultivars with a higher yield potential and the adoption of new technology have achieved high grain yields in common bean, which probably changed the demand for nutrients in this crop. However, there is almost no information about the periods of the cycle in which nutrients are most demanded at which quantities by the main cultivars. The objective of this study was to evaluate the macronutrient extraction and exportation by the common bean cultivars Pérola and IAC Alvorada, under different levels of NPK fertilization, on a dystroferric Red Nitosol, in Botucatu, São Paulo State, Brazil. The experiment was arranged in a randomized complete block (split plot) design with four replications. The plots consisted of six treatments based on a 2 x 3 factorial model, represented by two cultivars and three NPK levels (PD0 - 'Pérola' without fertilization, PD1 - 'Pérola' with 50 % of recommended fertilization, PD2 - 'Pérola' with 100 % of recommended fertilization, AD0 - 'IAC Alvorada' without fertilization, AD1 - 'IAC Alvorada' with 50 % of recommended fertilization, and AD2 - 'IAC Alvorada' with 100 % of recommended fertilization) and subplots sampled seven times during the cycle. At higher levels of NPK fertilization, the grain yield and macronutrient extraction and exportation of both cultivars were higher, but without statistical differences. Macronutrient absorption was higher in the treatments with 100 % of recommended NPK fertilization (average amounts per hectare: 140 kg N, 16.5 kg P, 120 kg K, 69 kg Ca, 17.9 kg Mg, and 16.3 kg S). Regardless of the treatment, the demand for N, P, K, Ca, and Mg was highest from 45 to 55 days after emergence (DAE), i.e., in the R7 stage (pod formation), while the highest S absorption rates were concentrated between 55 and 65 DAE. More than 70 % of P, between 58 and 69 % of N, 40 and 52 % of S, 40 and 48 % of K, and 35 and 45 % of Mg absorbed during the cycle was exported with grains, whereas less than 15 % of Ca was exported.

Nutrient extraction and exportation by common bean cultivars under different fertilization levels: II - micronutrients

Where the level of agricultural technology is higher, common bean cultivars with a higher yield potential possibly require greater amounts of micronutrients. In Brazil however, there is a lack of information about the micronutrient extraction and exportation by the main grown cultivars. The objective of this study was to evaluate micronutrient (B, Cu, Fe, Mn, and Zn) extraction and exportation by common bean cultivars Pérola and IAC Alvorada, under different levels of NPK fertilization, on a dystroferric Red Nitosol, in Botucatu, São Paulo State, Brazil. The experiment was arranged in a randomized complete block (split plot) design with four replications. The plots consisted of six treatments based on a 2 x 3 factorial model, represented by two cultivars and three NPK levels (PD0 - 'Pérola' without fertilization, PD1 - 'Pérola' with 50 % of recommended fertilization, PD2 - 'Pérola' with 100 % of recommended fertilization, AD0 - 'IAC Alvorada' without fertilization, AD1 - 'IAC Alvorada' with 50 % of recommended fertilization, and AD2 - 'IAC Alvorada' with 100 % of recommended fertilization) and subplots sampled seven times during the cycle. Higher levels of NPK fertilization increased micronutrient extraction by both cultivars, and treatments with 100 % of recommended NPK fertilization extracted on average 167 g B, 58 g Cu, 1,405 g Fe, 1,213 g Mn and 211 g Zn per hectare. Regardless of the treatment, the highest demand period for B, Cu, Fe, Mn and Zn in both cultivars occurred at the R7 stage (pod formation), i.e. 42 to 55 days after emergence (DAE). The amount of B, Cu, Fe, Mn and Zn exported depended mainly on the level of NPK fertilization used, with values per hectare ranging from 38 to 90 g of B, 12 to 26 g of Cu, 222 to 568 g of Fe 234 to 467 g of Mn, and 40 to 96 g of Zn.

Genotypic variability in seed accumulation of foliar-applied molybdenum to common bean

The genotypic variability in molybdenum (Mo) accumulation in common bean seeds has been demonstrated in cases in which soil is the main Mo source, but this variability is yet unknown when Mo is foliar-applied. Therefore, seed Mo concentrations (SMoCc) and seed Mo contents (SMoCt) of 12 genotypes were determined in four experiments in the Zona da Mata, Minas Gerais, Brazil, in which plants were sprayed with 600 g ha-1 Mo. For comparison, two additional experiments without external Mo were conducted. Without Mo application, the average SMoCc was undetectable or 2.83 µg g-1, without significant differences among genotypes. On average, with Mo applications, SMoCc ranged from 14.7 to 25.0 µg g-1 and SMoCt, from 3.94 to 6.84 µg. 'Majestoso' was among the genotypes with the highest SMoCc in the four experiments. However, the large-seeded 'Jalo MG-65' and 'Carnaval' generally had higher SMoCt than the small-seeded 'Majestoso'. 'Ouro Negro' and especially 'Valente' were among the genotypes with the lowest SMoCc and SMoCt. The values of these variables were 61 and 90 %, respectively, higher for 'Majestoso' than those for 'Valente'. Our results suggest that common bean genotypes differ in their capacity to accumulate foliar-applied Mo in the seeds. Mo-rich seeds of large-seeded genotypes or of small-seeded of small-seeded genotypes with good capacity to accumulate Mo in seeds can be produced with relatively less Mo fertilizer.

Variability of root traits in common bean genotypes at different levels of phosphorus supply and ontogenetic stages

Selection of common bean (Phaseolus vulgaris L.) cultivars with enhanced root growth would be a strategy for increasing P uptake and grain yield in tropical soils, but the strong plasticity of root traits may compromise their inclusion in breeding programs. The aim of this study was to evaluate the magnitude of the genotypic variability of root traits in common bean plants at two ontogenetic stages and two soil P levels. Twenty-four common bean genotypes, comprising the four growth habits that exist in the species and two wild genotypes, were grown in 4 kg pots at two levels of applied P (20 and 80 mg kg-1) and harvested at the stages of pod setting and early pod filling. Root area and root length were measured by digital image analysis. Significant genotype × P level and genotype × harvest interactions in analysis of variance indicate that the genotypic variation of root traits depended on soil nutrient availability and the stage at which evaluation was made. Genotypes differed for taproot mass, basal and lateral root mass, root area and root length at both P levels and growth stages; differences in specific root area and length were small. Genotypes with growth habits II (upright indeterminate) and III (prostrate indeterminate) showed better adaptation to limited P supply than genotypes of groups I (determinate) and IV (indeterminate climbing). Between the two harvests, genotypes of groups II and III increased the mass of basal and lateral roots by 40 and 50 %, respectively, whereas genotypes of groups I and IV by only 7 and 19 %. Values of the genotypic coefficient of determination, which estimates the proportion of phenotypic variance resulting from genetic effects, were higher at early pod filling than at pod setting. Correlations between shoot mass and root mass, which could indicate indirect selection of root systems via aboveground biomass, were higher at early pod filling than at pod setting. The results indicate that selection for root traits in common bean genotypes should preferentially be performed at the early pod-filling stage.

Water infiltration in an ultisol after cultivation of common bean

Water infiltration in the soil is an important hydrological process that occurs at the interface of the soil-atmosphere system; thus, the soil management practice used has a strong influence on this process. The aim of this study was to evaluate water infiltration in the soil and compare equations for estimating the water infiltration rate in an Ultisol after harvesting common bean (Phaseolus vulgaris L.) under simulated rainfall. Field tests with a rainfall simulator were carried out in three soil management systems: minimum tillage (MT), conventional tillage (CT), and no tillage (NT). In NT, four levels of plant residue on the soil surface were evaluated: 0, 3, 6, and 9 t ha-1. The models of Kostiakov-Lewis, Horton, and Philip were used to estimate the infiltration rate. In the MT system, the final infiltration rate was 54 mm h-1, whereas in the CT and NT systems with up to 3 t ha-1 of plant residue on the soil surface, the rate was near 17 mm h-1. In addition, the results indicated that in the NT system the infiltration rate increased with plant residue coverage greater than 6 t ha-1, i.e., there was a positive correlation between plant cover and the water infiltration rate. The Horton model was the most suitable in representing the water infiltration process in the soil. Therefore, this model can be recommended for estimation of this variable regardless of the soil tillage system used.

Linguagem, cultura e alteridade: imagens do outro

A interação a um só tempo complementar e conflitiva de três temas: linguagem, cultura e alteridade, constituem o eixo de um debate sobre a infância e a criança portadora de marcas sociais e étnicas. Na medida em que a percepção do social se prende a princípios e a valores considerados universais, verdadeiros, legítimos e únicos, que precisam ser relativizados, questiona-se o fato de a cultura e a alteridade se expressarem por linguagens nem sempre visíveis e explícitas, que exigem um olhar atento e aprofundado nas muitas realidades do campo social e no seu cotidiano como meio de compreender-lhes seus muitos significados. Crianças pobres de periferia urbana e do meio rural, crianças brancas, negras e mestiças e, ainda, crianças de rua, emprestam-nos suas falas e imagens construídas com desenhos, para expressar a sua percepção do meio em que vivem. Tais expressões referem-se também à escola que aí está, a seus processos e agentes para dizer, por meio de outras linguagens, como olham seu mundo e como são olhados por ele.

A apropriação da linguagem escrita e o trabalho alfabetizador na escola

O artigo apresenta um estudo do processo de produção de textos escritos vivenciado por dez crianças de 6 anos em uma classe de alfabetização. O trabalho pedagógico realizado pela professora tem relevância teórica e metodológica para este estudo. Dois objetivos foram definidos: (i) caracterizar as estratégias utilizadas pelas crianças para se aproximarem das convenções do sistema de escrita, notadamente, o princípio alfabético e a segmentação do texto em palavras; e (ii) caracterizar a atividade de elaboração e reelaboração do conhecimento lingüístico, evidenciando a atividade epilingüística das crianças e deixando emergir o sujeito da/na linguagem. São analisados 115 textos, produzidos ao longo de um semestre. É utilizada uma metodologia de investigação indiciária, com base em Ginzburg (1989). A análise dos dados apontou estratégias singulares e estratégias comuns de aproximação do sistema de escrita pelas crianças. Os saberes advindos dos textos escritos a que as crianças têm acesso, principalmente, organizaram as suas produções. A atividade epilingüística se manifestou durante todo o período estudado, em vários níveis. Concluo que o percurso de produção dos textos escritos é próprio de cada sujeito: o processo funda-se na escrita social e converge para a escrita social por caminhos singulares.

Relação entre desempenho infantil em linguagem escrita e percepção do professor

Esta pesquisa teve como objetivo investigar a relação entre o desempenho em leitura e escrita de palavras e de texto de 110 crianças de 2ª série de escolas públicas e o julgamento do professor sobre tais habilidades. Foram encontradas correlações significativas entre o desempenho dos alunos e a percepção do professor sobre essas habilidades. A avaliação do professor sobre a competência em leitura do aluno ao final do ano letivo mostrou-se um fator sensível na determinação de diferenças de desempenho dos alunos. Apesar das correlações positivas encontradas, houve algumas discrepâncias entre o julgamento do professor e as avaliações. O estudo sugere que o professor tem um conhecimento que o habilita a classificar as habilidades de leitura e escrita de seus alunos de forma relacionada ao desempenho deles, do ponto de vista da avaliação com base na psicologia cognitiva.

A linguagem oral como elemento integrante da brincadeira

Este texto discute a importância da brincadeira infantil para o desenvolvimento da linguagem oral nas crianças. É o desdobramento de pesquisa que investigou o trabalho com a linguagem em uma instituição educativa infantil que atende crianças de 2 a 6 anos de idade. O estudo de caso utilizou como técnica de coleta dos dados a observação participante. Conclui que as crianças recriam, nas brincadeiras, situações vivenciadas nas diversas esferas de comunicação humana das quais participam e, portanto, que as brincadeiras são de natureza cultural. Acentua, ainda, a importância do trabalho colaborativo para o desenvolvimento infantil

Diferenças conceituais sobre termos e definições e implicações na organização da linguagem documentária

A definição é um instrumento importante na elaboração de uma linguagem de organização da informação, porém nem sempre ela pode ser desenhada segundo os moldes prescritos pelas normas terminológicas. Propomo-nos a reunir alguns elementos para compreender o que é uma definição, como ela é elaborada segundo diferentes pontos de partida e objetivos, quais as dificuldades encontradas na utilização das prescrições da terminologia clássica e das normas terminológicas no tratamento dos discursos das humanidades e das áreas em formação ou transformação, e que alternativas são apontadas para seu enfrentamento. Parte-se do princípio de que, se a transferência da informação ocorre no universo da linguagem, é necessário observar as diferentes tipologias discursivas e sua terminologia, sob pena de comprometer a comunicação em ambientes informacionais.