Scielo RSS <![CDATA[Bragantia]]> http://www.scielo.br/rss.php?pid=0006-870520150002&lang=pt vol. 74 num. 2 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.br/img/en/fbpelogp.gif http://www.scielo.br <![CDATA[Root growth and distribution in sugarcane cultivars fertigated by a subsurface drip system]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200131&lng=pt&nrm=iso&tlng=pt Despite of the agronomic importance for water management, few studies of sugarcane roots have been performed under field conditions during the crop cycle. The aim of this study was to determine the cumulative root density (LA), root distribution on soil profile and the effective rooting depth (ERD) for three sugarcane cultivars using the minirhizotron method. A field experiment was done with sugarcane cultivars IACSP94-2094, IACSP94-2101 and SP79-1011 grown under subsurface drip fertigation. Soil chemical and physical characteristics were also evaluated. Root evaluations were taken at 38, 58, 123, 185 and 205 days during the second ratoon, considering the soil profile until 0.8 m depth. The highest LA and root growth rates were found up to 0.4 m soil layer for all cultivars. Root growth rate varied during the crop cycle, with the highest values being found between 38 and 58 days after ratoon (DAR). There was a genotypic variation in root growth, with IACSP94-2101 showing the highest LA of 12.9 mm cm–2. The total root length observed around the tube (0.16892 m2) was 10.8, 5.9 and 2.5 m up to 0.8 m depth for IACSP94-2101, SP79-1011 and IACSP94-2094, respectively at 205 DAR. The effective rooting depth varied during the cycle for IACSP94-2094, but all cultivars presented an effective depth of 0.4 m at 205 DAR. <![CDATA[Estimação da área foliar de canola por dimensões foliares]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200139&lng=pt&nrm=iso&tlng=pt O objetivo deste trabalho foi modelar e identificar os melhores modelos para a estimação da área foliar determinada por fotos digitais, de três híbridos de canola, em função do comprimento, ou da largura e/ou do produto comprimento vezes largura do limbo foliar. Foram conduzidos três ensaios de uniformidade com canola (Brassica napus L.), e em cada ensaio avaliou-se um dos seguintes híbridos: Hyola 61, Hyola 76 e Hyola 433. Em cada híbrido, foram coletadas 125 folhas aos 77, 84, 91 e 97 dias após a semeadura, totalizando 1.500 folhas. Nessas 1.500 folhas, foram mensurados o comprimento (C) e a largura (L), e calculado o produto do comprimento vezes a largura (C×L) do limbo foliar. Determinou-se a área foliar de cada folha, por meio do método de fotos digitais (Y). Posteriormente, para cada híbrido, foram separadas, aleatoriamente, 80% das folhas (100 folhas por coleta × 4 coletas por híbrido = 400 folhas por híbrido) para a geração de modelos do tipo quadrático, potência e linear, de Y em função do C, da L, e/ou do C×L. Os 20% das folhas restantes (100 folhas por híbrido) foram usadas, separadamente, para a validação dos modelos. Em canola, os modelos do tipo potência, para os híbridos Hyola 61 (Ŷ = 1,3000x1,9336, R2 = 0,9531), Hyola 76 (Ŷ = 1,0579x2,0383, R2 = 0,9733) e Hyola 433 (Ŷ = 1,4154x1,9096, R2 = 0,9613), são adequados para a estimação da área foliar determinada por fotos digitais (Y) em função da largura do limbo foliar (x).<hr/>The objective of this work was to model and identify the best models to estimate the leaf area determined by digital photos, of three canola hybrid, with the length or width and / or the product length width of the leaf. Three uniformity trials were carried with the culture of canola (Brassica napus L.). In each trial was valued one of the following hybrids: Hyola 61, Hyola 76, Hyola 433. In each hybrid were collected 125 leaves at 77, 84, 91, 97 days after sowing, totaling 1,500 leaves. In these 1,500 leaves were measured length (C) and width (L) and calculated the length width (C×L) of the leaf. Was determined the leaf area of each leaf, by the method of digital photos (Y). After, for each hybrid were separated, randomly, 80% of the leaves (100 leaves by collects × 4 collects by hybrid = 400 leaves per hybrid) to build models of quadratic, potency and linear type for Y function of the C, L and/or C×L. The remaining 20% of the leaves (100 leaves by hybrid), separately, were used to validate the models. In canola, the potency model for hybrid Hyola 61 (Ŷ = 1.3000x1.9336, R2 = 0.9531), Hyola 76 (Ŷ = 1.0579x2.0383, R2 = 0.9733) and Hyola 433 (Ŷ = 1.4154x1.9096, R2 = 0.9613), are adequate for estimation of leaf area determined by digital photos (Y) as function of the width of the leaf (x). <![CDATA[Análise da capacidade combinatória em feijoeiro comum submetido ao déficit hídrico]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200149&lng=pt&nrm=iso&tlng=pt O trabalho teve como objetivo estudar o comportamento de genitores de feijoeiro para compor um programa de melhoramento visando à tolerância à seca. A capacidade geral e específica de combinação das cultivares foram avaliadas utilizando genitores identificados como tolerantes à seca (BAT 477 e SEA 5), genitores desenvolvidos pelo Instituto Agronômico – IAC (IAC Alvorada e IAC Carioca Tybatã) e suas progênies, oriundas de um dialelo completo, incluindo os recíprocos. A semeadura foi realizada em solo, usando delineamento de blocos casualizados com três repetições, tanto para o experimento com irrigação como para o experimento com déficit hídrico, aplicado a partir do pré-florescimento. As plantas submetidas ao déficit hídrico permaneceram nessa condição por um período de 30 dias. Foram avaliados caracteres fisiológicos, morfológicos, componentes de produção e produtividade de grãos, observando-se a presença de efeitos aditivos e não aditivos no controle das características, além de indicar que os genitores empregados no estudo contribuíram de forma diferenciada nos cruzamentos de que participaram. Considerando o déficit hídrico na pré-floração, os genitores SEA 5 e IAC Alvorada apresentaram efeitos positivos quanto à capacidade geral de combinação para os caracteres produtividade e massa de mil grãos, enquanto o genitor SEA 5 também destacou-se com efeito positivo em relação ao número de sementes por vagem, sugerindo o incremento para essas características nos cruzamentos dos quais participaram. O cruzamento SEA 5 × IAC Alvorada destacou-se para a característica produtividade de grãos por apresentar maior efeito positivo para capacidade específica de combinação e por ter como genitores as cultivares que apresentaram valores positivos para capacidade geral de combinação.<hr/>This paper aimed at selecting parents to compose a common bean breeding program for drought tolerance. General and specific combining abilities were evaluated under controlled conditions, using drought tolerant parents (BAT 477 and SEA 5), elite cultivars developed at IAC (IAC Alvorada and IAC Carioca Tybatã) and their progenies obtained from a complete diallel, including the reciprocals. Sowing was done in soil following a randomized block design with three replications for both experiments, the control with irrigation and the drought stress experiment imposed from pre-flowering stage. Plants remained under drought stress for 30 days. Physiological and morphological traits as well as yield components and grain yield were evaluated, detecting additive and non-additive effects controlling these traits. The parents used in this study had contributed in different proportions in the crosses they participated in. Regarding the drought stress condition in the pre-flowering stage, the parents SEA 5 and IAC Alvorada presented greater positive effects for the general combining ability for the yield and weight of one thousand seeds, whereas the parent SEA 5 also showed a positive effect for the number of seeds per pod, suggesting the increase of these traits in the crosses they participated in. The hybrid combinations SEA 5 × IAC Alvorada showed a positive result for grain yield, related to the higher positive effect for specific combining ability and because they have as parents the cultivars which confer the best positive values for general combining ability. <![CDATA[Genetic divergence among maize hybrids by morphological descriptors]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200156&lng=pt&nrm=iso&tlng=pt Two experiments with 25 maize commercial hybrids were carried out in a direct sowing system in Southern Brazil in the harvests of 2009/2010 and 2010/2011. Quantitative descriptors were used with the objective of determining the genetic divergence and the relative contributions of traits among hybrids for extraction of inbred lines. This study was carried out in Oxisol soil using a randomized block design with four replicates. Data were subjected to combined analysis of variance, and based on the multivariate analyses, Tocher and average linkage (UPGMA) cluster analyses, based on generalized distance of Mahalanobis, to quantify divergence in addition to Singh criterion to validate trait with the most contribution. The multivariate methods were consistent with each other, and the weight of 100 grains was the trait that contributed most to the divergence and had similar behavior in grain yield between hybrids in both years. Furthermore, this descriptor representing significant genetic variability for crossings and lines extraction to hybridization between BM 3061, ATL 200 and P 30B39 Y. <![CDATA[Número de repetições para avaliação de caracteres em genótipos de feijão-caupi]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200161&lng=pt&nrm=iso&tlng=pt O objetivo deste trabalho foi determinar o número de medições (repetições) necessário para avaliar caracteres de genótipos de feijão-caupi (Vigna unguiculata). Vinte genótipos de feijão-caupi de porte ereto e vinte de porte semiprostrado foram avaliados no Estado do Mato Grosso do Sul, em seis e quatro ensaios, respectivamente. Os dez ensaios foram conduzidos no delineamento blocos ao acaso, com quatro repetições. Foram mensurados os caracteres comprimento de vagem, massa de vagem, massa de grãos por vagem, número de grãos por vagem, massa de cem grãos e produtividade de grãos. Foram verificados os pressupostos do modelo matemático, realizada a análise de variância, estimado o coeficiente de repetibilidade e calculado o número de repetições. Ensaios com quatro repetições identificam genótipos superiores de feijão-caupi em relação aos caracteres comprimento de vagem, massa de vagem, massa de grãos por vagem, número de grãos por vagem, massa de cem grãos e produtividade de grãos, com, respectivamente, 84,57, 75,62, 73,14, 75,25, 81,53 e 79,19% de exatidão no prognóstico de seu valor real.<hr/>The objective of this study was to determine the number of measurements (replicates) necessary to predict the performance of cowpea (Vigna unguiculata) genotypes. Twenty genotypes of cowpea to growth habit erect and twenty semi-prostrate were carried out in Mato Grosso do Sul State, Brazil, in six and four trials, respectively. It was conducted ten trials in randomized complete blocks design with four replicates. The character length of pod, weight of pod, weight of grains per pod, number of seeds per pod, weight of hundred grains and grain yield were measured. Assumptions of the mathematical model were examined, analysis of variance was performed, the repeatability coefficient was estimated and the number of replicates was calculated. Trials with four replicates identify superior cowpea genotypes in relation to length of pod, weight of pod, weight of grains per pod, number of seeds per pod, weight of hundred grains and grain yield characters, with, respectively, 84.57, 75.62, 73.14, 75.25, 81.53 and 79.19% accuracy of the true prognostic value. <![CDATA[Genetic divergence among cupuaçu accessions by multiscale bootstrap resampling]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200169&lng=pt&nrm=iso&tlng=pt This study aimed at investigating the genetic divergence of eighteen accessions of cupuaçu trees based on fruit morphometric traits and comparing usual methods of cluster analysis with the proposed multiscale bootstrap resampling methodology. The data were obtained from an experiment conducted in Tomé-Açu city (PA, Brazil), arranged in a completely randomized design with eighteen cupuaçu accessions and 10 repetitions, from 2004 to 2011. Genetic parameters were estimated by restricted maximum likelihood/best linear unbiased prediction (REML/BLUP) methodology. The predicted breeding values were used in the study on genetic divergence through Unweighted Pair Cluster Method with Arithmetic Mean (UPGMA) hierarchical clustering and Tocher’s optimization method based on standardized Euclidean distance. Clustering consistency and optimal number of clusters in the UPGMA method were verified by the cophenetic correlation coefficient (CCC) and Mojena’s criterion, respectively, besides the multiscale bootstrap resampling technique. The use of the clustering UPGMA method in situations with and without multiscale bootstrap resulted in four and five clusters, respectively, while the Tocher’s method resulted in seven clusters. The multiscale bootstrap resampling technique proves to be efficient to assess the consistency of clustering in hierarchical methods and, consequently, the optimal number of clusters. <![CDATA[Tamanho de parcela e número de repetições em canola]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200176&lng=pt&nrm=iso&tlng=pt Os objetivos deste trabalho foram determinar o tamanho ótimo de parcela e o número de repetições, para avaliar a massa verde de canola (Brassica napus L.). Foram realizados 27 ensaios de uniformidade de 5m×5m (25m2), sendo nove ensaios para cada um dos seguintes híbridos: Hyola 61, Hyola 76 e Hyola 433. Cada ensaio foi dividido em 25 unidades experimentais básicas (UEB) de 1m×1m, totalizando 675 UEB. Foi pesada a massa verde das plantas de cada UEB. O tamanho ótimo de parcela (Xo) foi determinado por meio do método da curvatura máxima do modelo do coeficiente de variação, e as comparações de médias, entre os híbridos, foram feitas pelo teste de Scott-Knott. O número de repetições, para experimentos nos delineamentos inteiramente casualizados e blocos ao acaso, em cenários formados pelas combinações de i tratamentos (i=3, 4, ..., 50) e d diferenças mínimas entre médias de tratamentos a serem detectadas como significativas a 5% de probabilidade, pelo teste de Tukey, expressas em percentagem da média do experimento (d=10%, 13%, ..., 40%), foi determinado por processo iterativo até a convergência. O tamanho ótimo de parcela para avaliar a massa verde de canola é 6,41m2. Quatro repetições, para avaliar até 50 tratamentos, nos delineamentos inteiramente casualizados e blocos ao acaso, são suficientes para identificar, como significativas a 5% de probabilidade, pelo teste de Tukey, diferenças entre médias de tratamentos de 41,4% da média do experimento.<hr/>The objectives of this work were to determine the optimum plot size and number of repetitions, to evaluate the fresh weight of canola (Brassica napus L.). Twenty-seven uniformity trials of 5m×5m (25m2) were conducted. Each trials was divided in 25 basic experimental units (BEU) of 1m×1m, totaling 675BEU. The fresh weight of plants, in each BEU was weighed. The optimum plot size (Xo) was determined by the method of maximum curvature of the model coefficient of variation and the means compared, among hybrids, by Scott-Knott test. The number of repetitions, for experiments on completely randomized and randomized block designs, in scenarios of combinations of i treatments (i=3, 4, ..., 50) and d minimal differences between treatments means, to be detected as significant, 5% probability by Tukey test, expressed in percentage of the average of the experiment (d=10%, 12%, ..., 40%), was determined by iterative process until convergence. The optimum plot size to evaluate the fresh weight of canola is 6.41 m2. Four replications, to evaluate up to 50 treatments, in completely randomized and randomized block designs, are sufficient to identify, as significant at the 5% probability by Tukey test, differences between treatment means 41.4% of the average experiment. <![CDATA[Produtividade de laranjeira Folha Murcha enxertada em limoeiro Cravo sob adensamento de plantio]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200184&lng=pt&nrm=iso&tlng=pt A citricultura brasileira passa por mudanças no padrão tecnológico, destacando-se o adensamento dos plantios. Dentro desse contexto, implantou-se em 1982 experimento para avaliação de cinco espaçamentos entre plantas (2,0; 3,0; 4,0; 5,0 e 6,0 metros) para laranjeira Folha Murcha, enxertada em limoeiro Cravo. O ensaio foi conduzido sem irrigação, fixando-se o espaçamento entrelinhas em 6,5 metros. Em complementação aos dados obtidos entre os anos de implantação e estabilização do pomar (1982 a 1993), são apresentados e discutidos neste trabalho resultados de avaliações realizadas do 12.o ao 22.º ano de cultivo (1994 a 2004). Calculou-se volume de copa a partir dos dados de altura e diâmetro das plantas, em 1995. Além disso, avaliou-se a produção de frutos por planta, produção acumulada e projeção da produtividade média (t ha–1) para cada espaçamento proposto. No espaçamento mais adensado (6,5×2,0 m), as plantas apresentaram menor volume de copa; em contrapartida, maior produtividade da laranjeira Folha Murcha foi observada nesse tratamento. Houve queda de produção nos anos mais avançados de cultivo, independentemente da densidade de plantio. O espaçamento 6,5×2,0 acarreta alta produtividade para laranjeira Folha Murcha, tornando a técnica do adensamento apta à adoção pelo citricultor.<hr/>The Brazilian citrus production comes through changes in technological standard, specially the high density of plantations. Within this context, was implemented in 1982, the experiment for evaluation of five plant spacings (2.0, 3.0, 4.0, 5.0 and 6.0 meters) to Folha Murcha sweet orange grafted on Rangpur. The test was conducted without irrigation, settling the line spacing of 6.5 meters. Complementing the data obtained in the years of deployment and stabilization of the orchard (1982 to 1993), are presented and discussed in this paper results of assessments carried between the 12th and 22nd years of cultivation (1994-2004). It was calculated canopy volume from the data of height and diameter of the plants in 1995. In addition, evaluated the production of fruits per plant and yield (t ha–1) for each spacing proposed. In the high density (6.5×2.0 m) the plants had lower canopy volume, on the other hand increased yield of the Folha Murcha sweet orange was observed in this treatment. There was production fall, in the final years of cultivation, regardless of plant density. The 6,5×2,0 m spacing leads to high productivity of Folha Murcha sweet Orange, making high density an apt technique to the adoption by the citrus producer. <![CDATA[Relationship between endogenous ethylene production and natural defoliation traits during the maturation of sugarcane]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200189&lng=pt&nrm=iso&tlng=pt The relationship between endogenous ethylene production and natural defoliation rate was examined in sugarcane cultivars with different natural defoliation traits. Ethylene production was examined at different positions on leaf sheaths and leaf scars at various sugarcane maturation stages using gas chromatography as an external standard method. During the sugarcane maturation process, ethylene production was greatest in the 2nd leaf sheath scar, followed by the 5th and 10th, in that order. It was also greatest during the early maturation stage, followed by the mid-maturation and harvest stages. Ethylene production of the leaf sheaths and leaf scars differed significantly among the sugarcane cultivars. Cultivars that defoliate easily produced significantly more ethylene than those that do not defoliate easily. The natural defoliation rates was greatest in the harvest stage, followed by mid-maturation and early maturation stage. Correlation analysis indicated that ethylene production was positively correlated with natural defoliation rates, particularly during early- and mid-maturation stages. <![CDATA[Effects of silicon on the penetration and reproduction events of <em>Meloidogyne exigua</em> on coffee roots]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200196&lng=pt&nrm=iso&tlng=pt Considering that the root-knot nematode Meloidogyne exigua has caused great yield losses to coffee production in Brazil, this study aimed to determine whether the penetration and the reproduction events of this nematode on the roots of plants from two coffee cultivars with different levels of basal resistance to this nematode could be affected by silicon (Si). Coffee plants from the cultivars Catuaí and IAPAR 59, which are susceptible and resistant, respectively, to M. exigua, were grown in pots containing Si-deficient soil that was amended with either calcium silicate (+Si) or calcium carbonate (–Si). The Si concentration on the root tissue significantly increased by 159 and 97% for the +Si plants from the cultivars Catuaí and IAPAR 59, respectively, compared to the –Si plants of these cultivars. The population of M. exigua, the number of galls and the number of eggs were significantly reduced on the roots of the +Si plants of the cultivars Catuaí and IAPAR 59 compared to the –Si plants of these cultivars. It was concluded that the development and reproduction events of M. exigua were negatively impacted on the roots of coffee plants supplied with Si. <![CDATA[Nitric oxide reduces oxidative damage induced by water stress in sunflower plants]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200200&lng=pt&nrm=iso&tlng=pt Drought is one of the main environmental constraints that can reduce plant yield. Nitric oxide (NO) is a signal molecule involved in plant responses to several environmental stresses. The objective of this study was to investigate the cytoprotective effect of a single foliar application of 0, 1, 10 or 100 µM of the NO donor sodium nitroprusside (SNP) in sunflower plants under water stress. Water stressed plants treated with 1μM SNP showed an increase in the relative water content compared with 0 μM SNP. Drought reduced the shoot dry weight but SNP applications did not result in alleviation of drought effects. Neither drought nor water stress plus SNP applications altered the content of photosynthetic pigments. Stomatal conductance was reduced by drought and this reduction was accompanied by a significant reduction in intercellular CO2 concentration and photosynthesis. Treatment with SNP did not reverse the effect of drought on the gas exchange characteristics. Drought increased the level of malondialdehyde (MDA) and proline and reduced pirogalol peroxidase (PG-POD) activity, but did not affect the activity of superoxide dismutase (SOD). When the water stressed plants were treated with 10 μM SNP, the activity of PG-POD and the content of proline were increased and the level of MDA was decreased. The results show that the adverse effects of water stress on sunflower plants are dependent on the external NO concentration. The action of NO may be explained by its ability to increase the levels of antioxidant compounds and the activity of ROS-scavenging enzymes. <![CDATA[Microscopic aspects of the colonization of <em>Pyricularia oryzae</em> on the rachis of wheat plants supplied with silicon]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200207&lng=pt&nrm=iso&tlng=pt Considering the importance of blast, caused by Pyricularia oryzae, to reduce wheat yield, this study investigate how silicon (Si) could reduce the wheat blast symptoms in the rachis tissues using light microscopy and scanning electron microscopy. Wheat plants (cv. BR 18) were grown in hydroponic culture with either 0 (–Si) or 2 mM (+Si) of Si. Blast symptoms were very well developed on the spikes of the –Si plants, which showed intense discoloration in contrast with the spikes of the +Si plants. At 72 hours after inoculation (hai), fungal hyphae extensively colonized the epidermis and the collenchyma tissue in the radial direction in the rachis of the –Si plants. In the +Si plants, fungal hyphae colonized the epidermis and the collenchyma cells to a lesser extent than in the –Si plants. At 96 hai, fungal hyphae were observed in the epidermis, vascular bundles and cortical tissue in the rachis node of the -Si plants. In the +Si plants, a phenolic-like material was detected in the parenchyma with lower fungal colonization in comparison with the –Si plants. In scanning electron microscopy, fungal hyphae were scarcely observed in the upper epidermal, collenchyma and parenchyma cells in the rachis tissue of the +Si plants, whereas in the rachis tissue of the –Si plants, fungal hyphae extensively colonized the epidermis, collenchyma, parenchyma and vascular bundles. <![CDATA[Distribuição espacial da condutividade elétrica do solo medida por indução eletromagnética e da produtividade de cana-de-açúcar]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200215&lng=pt&nrm=iso&tlng=pt A agricultura atual requer a inserção de novas tecnologias que permitam a identificação dos padrões de solo e planta, possibilitando a determinação da sua variabilidade espacial. O objetivo deste trabalho foi determinar a relação espacial entre a produtividade da cana-de-açúcar, da condutividade elétrica do solo medida por indução eletromagnética e da textura do solo. A área experimental está localizada em Goiana (Pernambuco, Brasil) (Latitude 07°34’25”S, Longitude 34°55’39”W). O experimento foi conduzido em uma área de 6,5 ha. A produtividade da cana-de-açúcar e a condutividade elétrica aparente do solo (CEa) foram medidas em 90 pontos de amostragem distribuídos aleatoriamente na área de estudo. Os mapas de condutividade elétrica do solo (CEa-V e CEa-H) apresentaram comportamento semelhante ao da produtividade de cana-de-açúcar. A correlação linear apresentou valores de 0,74 (produtividade x CEa-H) e 0,85 (produtividade x CEa-V). A condutividade elétrica medida por indução eletromagnética apresentou-se como uma ferramenta importante para a previsão da produtividade da cana-de-açúcar. Os atributos texturais (argila, silte e areia) apresentaram elevada variabilidade espacial.<hr/>The current agriculture requires the use of new technologies that allow the identification of soil and plant patterns, and the determination of their spatial variability. This work determined the spatial relationship between the sugar cane yield and soil apparent electrical conductivity (ECa) measured by electromagnetic induction (EMI) and soil texture. The experimental area is located in Goiana (Pernambuco State, Brazil) (07°34’25”S, 34°55’39”W). The experimental area was 6.5 ha. Sugar cane yield and soil apparent electrical conductivity (ECa) were measured at 90 sampling points randomly distributed in the study area. Maps of soil electrical conductivity (ECa-V and ECa-H) were similar to that of sugar cane yield. The linear correlation showed values of 0.74 (yield x ECa-H) and 0.85 (yield x ECa-V). The electrical conductivity measured by electromagnetic induction has been shown to be an important tool for predicting the yield of sugar cane. The textural properties (clay, silt and sand) showed high spatial variability. <![CDATA[Perdas e custos associados à erosão hídrica em função de taxas de cobertura do solo]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200224&lng=pt&nrm=iso&tlng=pt O objetivo deste estudo é estimar custos da erosão hídrica associados às perdas de nutrientes em quatro taxas de cobertura artificial do solo. O experimento foi conduzido de 1987 a 1996, em talhões coletores de perdas por erosão, em Campinas (SP), em Latossolo Vermelho distroférrico, sob chuva natural. O delineamento experimental foi inteiramente ao acaso, com quatro tratamentos (taxas de cobertura do solo: 0%, 24%, 40% e 90%) e três repetições. Para estimar os custos, os teores de P, K+, Ca2+ e Mg2+ na água da enxurrada e na terra carreada pela erosão foram somados, convertidos em superfosfato triplo, cloreto de potássio e calcário dolomítico, e multiplicados pelos seus preços de mercado. Os resultados indicam, para as condições experimentais, que quanto maior o percentual de cobertura do solo, menores as perdas de água, terra, matéria orgânica e nutrientes. O solo com 90% de cobertura, em comparação àquele com 0%, reduziu as perdas médias de água em 51,97%, de terra em 54,44% e de matéria orgânica em 54,91%. Em solo sem cobertura, foram estimadas perdas de 16% de P2O5 e 8% de KCl em relação à quantidade de fertilizantes recomendada. Os custos variaram de US$ 107,76 ha–1 ano–1 no solo com 0% de cobertura a US$ 18,15 ha–1 ano–1 no solo com 90%. A partir desses valores, estimaram-se para o Brasil perdas de 616,5 milhões de toneladas de terra ao ano, decorrentes do processo de erosão do solo em lavouras anuais, e custos da ordem de US$ 1,3 bilhão ao ano.<hr/>The aim of this study was to estimate water erosion costs associated with nutrient losses in four different rates of artificial cover. The experiment was carried out from 1987 to 1996 in runoff plots to measure soil losses in Campinas, State of Sao Paulo, in an Ferralsol under natural rainfall. The experimental design was completely randomized, with four treatments (0%, 24%, 40% and 90% artificial cover) and three replications. To estimate costs, P, K+, Ca2+ and Mg2+ concentrations in runoff water and soil removed by erosion were summed up, converted into triple superphosphate, potassium chloride and dolomitic limestone and multiplied by their respective market prices. The results indicate that, under the experimental conditions, the greater the percentage of soil cover, the lower the losses of water, soil, organic matter and nutrients. The soil with 90% cover presented reduction of 51.97% in average water losses, 54.44 in soil losses and 54.91% in organic matter losses than the treatment with 0% cover. In bare soil, losses were estimated at 16% P2O5 and 8% KCl in terms of the amount of fertilizers recommended. Costs varied from US$ 107.76 ha–1 year–1 in bare soil (0% cover) to US$ 18.15 ha–1 year–1 in soil with 90% cover. With these values, losses were estimated at 616.5 million tons of soil per year for Brazil, as a result of soil erosion in annual crops, and cost of this process is around US$ 1.3 billion per year. <![CDATA[Balanço de energia e consumo hídrico de vinhedo de ‘Cabernet Franc’]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200234&lng=pt&nrm=iso&tlng=pt O método do balanço de energia foi utilizado em vinhedo da uva para vinho ‘Cabernet Franc’, conduzido em espaldeira alta, para caracterizar a repartição do saldo de radiação (SR) nos diferentes fluxos de calor: latente (LE), sensível e no solo. Em média LE representou aproximadamente 79% de SR. São apresentadas as variações horárias dos componentes do balanço de energia para dias: ensolarado e nublado. O consumo hídrico do vinhedo para os diferentes subperíodos fenológicos foi: poda-florescimento (99 mm), florescimento-início de maturação (249 mm) e início de maturação-colheita (201 mm). Para o ciclo total (poda-colheita), o consumo hídrico obtido foi de 549 mm.<hr/>The energy balance method was used on a ‘Cabernet Franc’ vineyard trained on a vertical trellis system with branches attached to four wires to characterize the partition of the net solar radiation (SR) into the latent (LE), sensible and soil heat fluxes. As an average LE represented 79% of SR. Hourly variation of the energy balance components for sunny and cloudy days are shown. The water consumption for the different phenological phases were: pruning-flowering (99 mm), flowering-veraison (249 mm); veraison-harvest (201 mm). Considering the entire cycle (pruning-harvest) the water consumption was 549 mm. <![CDATA[Errata]]> http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0006-87052015000200239&lng=pt&nrm=iso&tlng=pt O método do balanço de energia foi utilizado em vinhedo da uva para vinho ‘Cabernet Franc’, conduzido em espaldeira alta, para caracterizar a repartição do saldo de radiação (SR) nos diferentes fluxos de calor: latente (LE), sensível e no solo. Em média LE representou aproximadamente 79% de SR. São apresentadas as variações horárias dos componentes do balanço de energia para dias: ensolarado e nublado. O consumo hídrico do vinhedo para os diferentes subperíodos fenológicos foi: poda-florescimento (99 mm), florescimento-início de maturação (249 mm) e início de maturação-colheita (201 mm). Para o ciclo total (poda-colheita), o consumo hídrico obtido foi de 549 mm.<hr/>The energy balance method was used on a ‘Cabernet Franc’ vineyard trained on a vertical trellis system with branches attached to four wires to characterize the partition of the net solar radiation (SR) into the latent (LE), sensible and soil heat fluxes. As an average LE represented 79% of SR. Hourly variation of the energy balance components for sunny and cloudy days are shown. The water consumption for the different phenological phases were: pruning-flowering (99 mm), flowering-veraison (249 mm); veraison-harvest (201 mm). Considering the entire cycle (pruning-harvest) the water consumption was 549 mm.