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Scientia Agricola, Volume: 81, Publicado: 2024
  • Physio-edaphoclimatic factors show optimal soil suitability for three tropical crops in the Ecuadorian Amazon Agrometeorology

    Vizuete-Montero, Marco Omar; Figueroa-Saavedra, Hilter Farley; Barbaru-Grajales, Asterio Denis; Zapata-Mayorga, Holger Alfredo; Herrera-Ocaña, Héctor Ramiro; Moya, Wladimir

    Resumo em Inglês:

    ABSTRACT Favorable soil conditions are essential to the proper growth and production of any crop worldwide. Only 9 % of the Ecuadorian Amazon Region (EAR) territory is suitable for agriculture and/or livestock farming, due to limitations imposed by physio-edaphoclimatic factors. This study evaluated the soil potential suitability for coffee, cocoa and tropical pastures to determine optimal, moderate and marginal areas in three provinces in the EAR (Orellana, Sucumbios and Pastaza) under different agroecological conditions. On-site field work was carried out to analyze the soil profile to determine the mineral composition. Eight environmental variables were evaluated through the integration of GIS-based modeling to determine the agroecological zoning of the crops. The results showed that the main determining factors for optimal areas of soil suitability within the three provinces included soil depth (30 cm), organic matter content (5.3 %), concentration of macronutrients (2,700 mg kg–1), and slope (< 10 %), whereas annual temperature (18-26 °C), annual precipitation (1200-3000 mm), altitude (0-500 m), and pH (4.38) were included for moderate and marginal areas. Depending on the crop and the province, soil suitability was classified into two or three classes (optimal, moderate, and marginal areas), relying on the agroecological conditions specific to each crop. This study highlights that all crops showed mostly optimal soil suitability for proper development under the agroecological conditions analyzed, which contributes to the provision of valuable information to decision-makers about key limiting factors, land-use planning and mapping soil suitability when considering the best location for a specific crop.
  • Differences between ecological niche models when predicting the potential distribution of soybean Agrometeorology

    Gong, Lijuan; Li, Xiufen; Liu, Dan; Jiang, Lixia; Jiang, Lanqi; Li, Yuguang

    Resumo em Inglês:

    ABSTRACT Against the background of a sharp decline in soybean planting, rising imports, and natural disasters in China, finding appropriate distribution areas for soybean has become a matter of urgency so that soybean planting policies can be formulated and soybean food security ensured. Among the numerous ecological niche models, the most suitable one for predicting potential distribution areas of soybean in the frigid region must be identified. Based on 65 soybean occurrence points and nine environmental variables, three ecological niche models, MaxEnt, BIOCLIM, and DOMAIN, were applied to the prediction of potential distribution areas for soybean. According to the analytical comparison, the three models predicted the potential distribution of soybean and, specifically, MaxEnt, stood out above the other two models as regards predicting the soybean distribution (Receiver Operating Characteristic curve, AUC = 0.916, Kappa = 0.685). The potential distribution areas (from low suitability to high suitability) predicted by MaxEnt was the largest and accounted for 59.5 % of the total area. The potential suitable distribution area of soybean was mainly concentrated in relatively flat terrain. The Sanjiang Plain and the Northeast Plain accounted for 9.4 % of the total area in the frigid region and are highly suitability for soybean. At the same time, annual mean temperature, elevation and Apr solar radiation were the key determinants affecting soybeans’ habitat. On the whole, the selection of ecological niche models and the prediction of soybean potential distribution can provide an essential reference for soybean planting and planning. Moreover, it would be a reliable example for the subsequent related research on soybean habitats.
  • Decision trees as a tool for selecting sows in commercial herds Animal Science And Pastures

    Hilgemberg, João Otávio; Andretta, Ines; Mariani, Alexandre Bonadiman; Neimaier, Alisson; Valk, Marcio; Bittarello, Fernando; Hilgemberg, Rafaela; Lehnen, Cheila Roberta

    Resumo em Inglês:

    ABSTRACT This study aimed to evaluate the use of decision trees to select sows based on the production parameters of parity order (PO) 1 sows from a commercial herd. Data were collected at a piglet production unit with a capacity of housing 5,500 sows in collective pens. Piglet production and sow culling information was collected from PO1 and PO2 sows. The period from January 2017 to March 2020 was analyzed. The correlation analysis was used to identify the influence of the production parameters on sow culling after exploring the database using the graphical analysis and descriptive statistics. The ANOVA was applied to evaluate differences in the response variables between culled and unculled sows. Two models were proposed using the decision tree method: model 1 referred to sow culling, and model 2 comprised the total number of liveborn piglets (TBA). The calculated value was close to 0, although the correlations of the production parameters with culling were statistically significant. The mean number of weaned piglets was higher for unculled sows in PO1 (p < 0.05). The number of weaned piglets, total number of liveborn piglets, and weaning-service interval did not differ in the unculled and culled sows in PO2 (p > 0.05). Using a confusion matrix as a metric tool, the decision tree method used in this study provided consistent results for this database, indicating its possible use for decision-making in sow selection.
  • Bayesian inference applied to soybean grown under different shading levels using the multiple-trait model Biometry, Modeling And Statistics

    Silva Júnior, Antônio Carlos da; Costa, Weverton Gomes da; Guimarães, Amanda Gonçalves; Moura, Waldênia de Melo; Campos, Leonardo José Motta; Rodrigues, Reimário de Castro; Bhering, Leonardo Lopes; Cruz, Cosme Damião; Evaristo, Anderson Barbosa

    Resumo em Inglês:

    ABSTRACT present study aimed to determine the effects of different light restriction levels (shading levels) on soybean genetic parameters using a Bayesian multi-trait model (MTM) and select high-yielding soybean cultivars. Eighteen commercial soybean cultivars bred in a soybean breeding program were evaluated over two agricultural seasons. Three shading levels were used over two agricultural crop seasons, giving six treatments (light restriction × crop season). The experiments were arranged in a randomized complete block design with six treatments replicated thrice. The genetic values and parameters were estimated using a Monte Carlo Markov Chain algorithm. Broad-sense heritability range from 0.2093 to 0.7153. The lowest genotypic variance estimate was observed at the 45 % photosynthetically active radiation level in the 2019/2020 crop season year compared with that of other shading levels. Furthermore, a 40 % selection intensity had the highest soybean yield under different shading levels. The Bayesian MTM combined with the factor analysis and genotype-ideotype distance method can be used to evaluate and select soybean genotypes considering different shading levels. The soybean cultivars 8579RSF, NS8338, NS7901, NS7667, RK8115, and 8473RSF had higher genetic potential than other cultivars under different shading levels.
  • Bayesian sequential estimation of the proportion of damage in maize seeds Biometry, Modeling And Statistics

    Lima, Isabela da Silva; Brighenti, Carla Regina Guimarães; Pires, Raquel Maria de Oliveira

    Resumo em Inglês:

    ABSTRACT Sampling is an essential step in estimating a parameter: thus, cost and time associated to this step should be minimized. Sequential sampling is characterized by using samples of variable sizes given as a function of observations, and sequential sampling provides a smaller sample size than a fixed-size sample in most cases. In addition, the Bayesian decision theory can be incorporated into sequential sampling to perform parameter estimation because it allows the inclusion of a priori information about the parameter of interest, which optimizes the procedure. However, the great challenge to performing the Bayesian sequential estimation in establishing the stopping criteria. Most studies in this area investigate binomial distributions, while few analyze multinomial distributions. This study aimed to define the stopping criteria for the Bayesian sequential estimation of the parameters of multinomial distributions with conjugate Dirichlet priors. The proposed methodology was applied to a set of X-ray test data for quality control of maize seed lots. This test uses conventional sampling techniques in which a sample has a fixed size with 200 seeds. The influence of two priors on the stopping criteria was evaluated, one uniform and one conjugate, with hyperparameters based on reference information from the literature. The results indicated a reduction in the sample size in most lots evaluated.
  • Best linear unbiased prediction in combination with path analysis in processing grapes Crop Science

    Rodrigues, Cinthia Souza; Moura, Mara Fernandes; Oliveira, Geovani Luciano de; Silva, Marlon Jocimar Rodrigues da; Tecchio, Marco Antonio

    Resumo em Inglês:

    ABSTRACT The knowledge of correlations between multiple characteristics in plant breeding leads to more effective selection strategies. The path analysis allows refining these correlations and partitioning them into direct and indirect effects on the main variable. The path analysis becomes more effective when based on predicted genotypic values rather than phenotypic values. The objective was to evaluate correlations between the main agronomic characteristics of grapevine cultivation and their direct and indirect effects on yield per plant to improve selection strategies to reach superior progenies. A randomized complete block design was installed using four cultivars and two rootstocks, five repetitions, and plots of four plants. Data from three crop seasons were analyzed from a mixed model and genetic correlations were subject to the path analysis. A high and positive significant correlation was found between average fruit production and the number of clusters per plant. On the other hand, the average production per plant showed a low correlation to cluster width and height per grapevine. Wider and higher berries tend to increase berry fresh mass and therefore increase the contents of soluble solids and reducing sugars. Among the features, the number of clusters per plant has the strongest direct effect on fruit production in grape cultivars. Berry fresh mass, berry length, and berry width were indirectly influenced by the number of clusters and showed high heritability compared to yield and number of clusters. These characteristics could be used in indirect selection.
  • Decomposition, biochemical composition and nutrient cycling of macauba palm in a Cerrado Entisol Crop Science

    Carvalho, Arminda Moreira de; Quintana, Luciane Gomes; Souza, Anderson Marcos de; Coser, Thais Rodrigues; Sousa, Thais Rodrigues de; Oliveira, Alexsandra Duarte de; Ramos, Maria Lucrecia Gerosa

    Resumo em Inglês:

    ABSTRACT Leaf litter decomposition and the release of nutrients from macauba palm leaves play a major role in nutrient return to the soil in a conservation environment. This study evaluated macauba palm leaf decomposition, macronutrient contents and biochemical composition under contrasting water conditions in the Brazilian Cerrado. Macauba leaves were collected from plants in two different environments (low and high water table conditions), placed in litter bags and evaluated according to their decomposition, macronutrients, lignin, cellulose and hemicellulose for 420 days. In addition, green and dry leaves were collected for macronutrient analyses. Litter decomposition ranged between 49 % and 59 % up to 180 days. The half-life of litter ranged from 141 to 198 days. The leaf litter decomposition of macauba was practically stable during the dry season, whereas at the beginning of the rainy season, decomposition resumed. Nitrogen, P and S were higher in the green leaves, whereas the Ca levels were higher in the dry leaves. In addition, the K levels were twofold higher in the green leaves than in the dry leaves. Lignin release from macauba residues was slower than cellulose and hemicellulose. The decomposition rates of hemicellulose were higher initially due to its high solubility, although it gradually decreased with the decomposition process. Lignin decomposition was also higher at the beginning of the process but stabilized during the drought period. The study indicates that the decomposition process and nutrient cycling of macauba are influenced by its biochemical composition.
  • Production, quality, bioactive compounds, and phenology of raspberry cultivars under an organic cropping system in a subtropical region of Brazil Crop Science

    Fagundes, Cintia de Moraes; Biasi, Luiz Antonio; Tofanelli, Mauro Brasil Dias; Rodrigues, Ana Paula Santos; Franciscon, Vitor Guimarães; Siqueira, Aline de Fátima Cobachuk

    Resumo em Inglês:

    ABSTRACT Studies on the adaptability of raspberry cultivars to subtropical regions are needed since growth, yield, and fruit quality may differ from levels observed in temperate climates. This study evaluated the phenology, yield, physical-chemical attributes, and bioactive compounds of raspberries produced in a subtropical region of Brazil under an organic cropping system. The experiment was carried out in three production cycles 2018/2019, 2019/2020, and 2020/2021 in Pinhais, Paraná State, Brazil. We evaluated ten raspberry cultivars, eight primocanes (Alemãzinha, Autumn Bliss, Bababerry, Fallgold, Golden Bliss, Heritage, Indian Summer and Polana), and two floricane cultivars (Schoenmann and Willamette). Phenological evaluations were carried out weekly at the beginning and end of flowering and harvesting. The soluble solids content, titratable acidity, the pH, and bioactive compounds were analyzed. Primocane cultivars showed two flowering and fruiting periods, the first in spring/summer and the other in summer/autumn, except for the Indian Summer cultivar, which showed a floricane-fruiting behavior, bearing fruit only on one-year-old canes, like Schoenmann and Willamette cultivars. ‘Alemãzinha’ shows better adaptation to the region under study with higher yield and concentration of total polyphenols, but its fruits are small and acidic. ‘Heritage’ is also an option for cultivation in this region, even though it is less productive, as the fruits are larger, less acidic, and have high levels of bioactive compounds. Yellow cultivars Fallgold and Golden Bliss are good options for diversifying the color offer, with yields similar to ‘Heritage’ and with a high total soluble solids/titratable acidity ratio.
  • Peach tree growth in a tropical climate: shoot formation and fruiting Crop Science

    Penso, Gener Augusto; Serafini, Gabriel Antônio Dalapícula; Santos, Carlos Eduardo Magalhães dos; Picoli, Edgard Augusto Toledo; Citadin, Idemir; Lauri, Pierre-Éric

    Resumo em Inglês:

    ABSTRACT This study aimed to characterize the occurrence, duration, and intensity of the flushes of vegetative growth in two peach cultivars of Prunus persica L. Batsch, grown as a pioneer endeavor at a high-altitude tropical climate site in the State of Minas Gerais, Brazil. The observational experiment was carried out in 2017/18 and 2018/19 on the ‘Tropic Beauty’ and ‘BRS Kampai’ cultivars by an evaluation of the number and duration of flushes of vegetative growth during the year over two cycles. The number of fruit-bearing shoots, total number of leaves and shoot length were also assessed. At harvest, fruit load and diameter were determined and grouped into diameter ranges. The number of hours recorded at different temperature ranges, < 10.0 °C; 10.1-15.0 °C; 15.1-20.0 °C; 20.1-25.0 °C; > 25.1 °C, were summed separately and divided into daily and nightly periods. The peach tree has an unusual vegetative growth pattern when cultivated in a tropical area, which occurs in two flushes, with the first flush occurring from budbreak to fruit harvest between June and Sept, forming short shoots (less than 10 cm), with early shoot growth cessation, with a limited leaf number that can potentially diminish the supply of carbohydrates to the fruit, leading to smaller growth. The second flush occurs after harvest, between Oct and Dec, when there is an increase in daily temperature and precipitation, and no competition with fruits. Notabily, these second flush shoots grow with greater vigor and regularization of the growth cycle, forming fruit-bearing shoots with abundant leaf and flower buds for the next production cycle.
  • Radiographic and spectral images of rice seeds and the photosynthetic efficiency of seedlings Crop Science

    Silva, Artur Sousa; Cicero, Silvio Moure; Gomes Junior, Francisco Guilhien

    Resumo em Inglês:

    ABSTRACT The development and the use of new technologies in agriculture contribute to significant advances in research with practical applications in several fields, such as image analytical techniques, which are simple, fast, and objective analyses. This work aimed to evaluate rice seeds’ quality using X-ray, multispectral, and chlorophyll fluorescence image analytical techniques and relate this information with the photosynthetic efficiency of seedlings. Initially, the seeds were identified and enumerated, then X-ray images were obtained, and the void space (area between the endosperm + embryo and the glumes) was calculated. Next, the same seeds were used in the X-rays, multispectral, and chlorophyll fluorescence images. Afterward, the seeds were placed to germinate in polyethylene cups with a capacity of 250 mL, and evaluations of the photochemical yield of photosynthesis photosystem II (FSII) and of the seedling fluorescence chlorophyll were carried out seven, nine, and 11 days after the emergence of the seedlings. The reflectance of seeds in the spectral bands between 365 nm and 780 nm showed a positive correlation with the chlorophyll fluorescence. Furthermore, the higher photosynthetic efficiency of rice seedlings at 11 days after emergence is directly related to the reflectance of the seeds at spectral bands between 365 nm and 780 nm.
  • Decomposition of sorghum, grass, and sorghum intercropped with grass and soybean performance in integrated systems in the Cerrado Crop Science

    Sodré Filho, Joilson; Carvalho, Arminda Moreira de; Marchão, Robélio Leandro; Carmona, Ricardo

    Resumo em Inglês:

    ABSTRACT Previous cultivation of sorghum (Sorghum bicolor), Congo grass (Urochloa ruziziensis), and palisade grass (Urochloa brizantha cv. ‘Marandu’) may influence soybean (Glycine max) agronomic performance. The present work evaluated the decomposition of sorghum, grass, and sorghum intercropped with grass in the off-season to improve soybean yield in integrated crop systems in the Brazilian Cerrado and their dry matter production. This study was conducted in Planaltina, DF, in Central-West Brazil, on a Typical Acrustox soil from Mar 2010 until Feb 2012. The experimental design was a randomized block, with six crop systems before soybean: fallowing, sorghum, palisade grass (alone or intercropped with sorghum), and Congo grass (alone or intercropped with sorghum) with four replicates. Soybean agronomic performance, the crop systems’ dry mass, and its decomposition rate were estimated over two years. Higher soybean grain yields were observed in cropping systems including Congo grass alone (3,349 kg ha–1) or intercropped with sorghum (3,317 kg ha–1). Sorghum intercropped with palisade grass produced 18,702 kg ha–1 of dry matter and 64.9 % (on average) of soil coverage during the soybean cycle. However, the highest lignin content was observed in sorghum intercropped with Congo grass (5.1 % on average). The results indicate that the cultivation of Congo grass, either alone or intercropped with sorghum, improves the agronomic performance of soybean in succession, compared to sorghum alone or palisade grass (alone or intercropped with sorghum). The intercropped systems provided the best nutrient efficiency use aiming at sustainable agriculture in the Cerrado region.
  • Influence of micronized salt and high-power ultrasound on the quality of beef burgers Food Science And Technology

    Araújo, Chimenes Darlan Leal de; Krauskopf, Monique Marcondes; Manzi, João Antônio Santos; Santos, Karoline Costa; Rios-Mera, Juan Dario; Dargelio, Mariana Damiames Baccarin; Saldaña, Erick; Castillo, Carmen Josefina Contreras

    Resumo em Inglês:

    ABSTRACT The study aimed to evaluate the combined use of ultrasound (US) and incorporation of micronized salt (MS) as a strategy for reducing sodium without affecting the quality of beef burgers. Ten treatments were manufactured with varying MS content (0.75 %, 1.0 %, and 1.5 %) and ultrasound time (0, 5, and 10 min), with a control treatment manufactured at 1.5 % of regular salt without ultrasound. The beef burgers formulated with 0.75 % MS submitted to the US for 10 min (M0.75US10) reduced the salt content by 50 %, thereby efficiently maintaining texture profile (hardness, springiness, cohesiveness, and chewiness) and decreasing the cooking loss and diameter reduction compared to the control treatment. M0.75US10 treatment also preserved the color of samples after cooking, keeping myoglobin stable. Therefore, micronized salt coupled with ultrasound technology reduces sodium chloride content in beef burgers, enabling the application of clean technology to reduce sodium content in meat products efficiently.
  • Association of polymorphisms in CAPN1 and CAST genes with the meat tenderness of Creole cattle Food Science And Technology

    Saucedo-Uriarte, José Américo; Portocarrero-Villegas, Segundo; Diaz-Quevedo, Clavel; Quispe-Ccasa, Hurley Abel; Tapia-Limonchi, Rafael; Chenet, Stella M.; Cesar, Aline Silva Mello; Cayo-Colca, Ilse Silvia

    Resumo em Inglês:

    ABSTRACT Single nucleotide polymorphisms are variations of a single nucleotide base pair and can be associated to phenotypic characteristics. This study aimed to determine the association of CAPN1 and CAST gene polymorphisms with the tenderness of Creole cattle meat from the Amazonas region, Peru. The texture profile (adhesiveness, cohesiveness, Warner-Bratzler shear force, elasticity, gumminess, and chewiness) of 100 animals was determined in 100 g of Longissimus dorsi et lumborum muscle. Allelic frequencies, genotypic frequencies, and Hardy-Weinberg equilibrium (HWE) of calpain (CAPN-316, CAPN-530) and calpastatin (CAST-2959) gene polymorphisms were studied. Allelic and genotypic frequencies were calculated, as well as the Hardy-Weinberg equilibrium with the Chi-square test. The texture profile of each group of samples corresponding to a polymorphism was compared with the Duncan’s test and the t-test for independent samples (p < 0.05). Genotypic frequencies were 78 % GG and 22 % CC for CAPN-316; 68 % GG, 5 % GA, and 27 % AA for CAPN-530; and 74 % AA, 18 % AG, and 8 % GG for CAST-2959. The CAPN-316, CAPN-530, and CAST-2959 polymorphisms were not in Hardy-Weinberg equilibrium. The CC genotype of CAPN-316 marker influences meat tenderness on day 21 of meat aging. In contrast, the GG genotype of CAST-2959 marker affects meat tenderness at days 14 and 21 of meat aging concerning the other genotypes.
  • Assessment of mutant rice genotypes on growth cycle length and response to reduced water availability Genetics And Plant Breeding

    Tejeda, Luis Herminio Chairez; Joseph, Raymond; Venske, Eduardo; Luz, Viviane Kopp da; Chacón-Ortiz, Andrés Eloy; Magalhães Júnior, Ariano Martins de; Maia, Luciano Carlos da; Oliveira, Antonio Costa de; Pegoraro, Camila

    Resumo em Inglês:

    ABSTRACT Rice (Oryza sativa) is among the most important crops worldwide; however, rice crops demand high water consumption. Future projections indicate reduced water availability and severe drought events, which may affect rice crops as the cereal is highly sensitive to drought stress. Thus, cultivars with lower water demand for irrigation or drought escape capacities are among the strategies to address this issue. This study aimed to assess five mutant rice genotypes in terms of growth cycle length, other agronomic interest traits, and drought response in the reproductive stage. The mutant genotypes evaluated showed a shortening of the growth cycle compared to the original cultivar, BRS Pampeira, representing a drought escape strategy. In addition, mutations did not negatively affect plant height and crop yield. However, similar to the original cultivar, mutants are not tolerant to water deficit in the reproductive stage. The genotypes evaluated have potential to be released as early cycle cultivars, which can reduce water demand during the harvest season while presenting a drought escape strategy.
  • Distribution of available nitrogen forms in soil under Quilombola management systems in Brazilian Cerrado phytophysiognomies Soils And Plant Nutrition

    Silva, Antonio Marcos Miranda; Ramos, Maria Lucrécia Gerosa; Nascimento, Robervone Severina de Melo Pereira do; Feiler, Henrique Petry; Silva, Stefany Braz; Cardoso, Elke Jurandy Bran Nogueira

    Resumo em Inglês:

    ABSTRACT Management of Quilombola systems are primitive agricultural systems based on the ancestral knowledge of Afro-Brazilian enslaved people. Here, the aim was to understand the impact of these primitive farming methods on the distribution of available nitrogen (N) forms in the soil profile of two Brazilian Cerrado phytophysiognomies. The soil was sampled in Cerradão (high Cerrado) and Cerrado Stricto sensu (low Cerrado) at six soil depths (0-10, 10-20, 20-30, 30-40, 40-50, and 50-60 cm). The following management systems were considered: pasture (PP1 and PP2), maize cultivation (M1 and M2), citrus-cassava intercropping (T1), and citrus monoculture (T2). In addition, the soil was sampled in the native area of Cerradão (NC1) and Cerrado Stricto sensu (NC2). Three N forms were determined: i) available nitrogen (Av-N), ii) ammonium (NH4+-N) and iii) nitrate (NO3–-N) contents. The Av-N content decreased with increasing soil depth only in NC1 and NC2. The NO3–-N content was similar at all soil depths for maize and pasture, while the content decreased at soil depth for NC1, NC2, and T1. NH4+-N was similar in M2 and PP2, but it increased in T2, ranging from 6.17 mg kg–1 to 17.54 mg kg–1. Overall, the dynamics of available N forms varied according to the Cerrado phytophysiognomy and the management systems and NO3–-N was the most constant N form in the soil profile. Therefore, although the management of Quilombola systems is less intensive, they negatively affect the dynamics and N availability, mainly where management is less conservative, that is, in maize and citrus monocultures.
  • Hierarchical pedotransfer functions for predicting bulk density in Brazilian soils Soils And Plant Nutrition

    Reis, Aline Mari Huf dos; Teixeira, Wenceslau Geraldes; Fontana, Ademir; Barros, Alexandre Hugo Cezar; Victoria, Daniel de Castro; Vasques, Gustavo Mattos; Samuel-Rosa, Alessandro; Ottoni, Marta Vasconcelos; Monteiro, José Eduardo Boffino de Almeida

    Resumo em Inglês:

    ABSTRACT Bulk density (BD) is a soil physical property used as a soil quality indicator and variations in this measurement influence soil water content and carbon stock estimates. This study aims to compile a database of samples of bulk density, textural fractions, and organic carbon values, as well as evaluate the accuracy of published pedotransfer functions (PTF) that predict bulk density, and propose a hierarchical PTF to predict the bulk density of Brazilian Soils. The performance of eleven PTFs and the newly proposed PTFs were evaluated and compared using the root mean square error (RMSE) and coefficient of determination (R2) based on a testing soil database collected from the literature. We noticed a slight improvement in accuracy when organic carbon and coarse and fine sand fractions were included as predictors alongside silt and clay. The best results with existing PTFs were obtained by PTF-A in Tomasella and Hodnett (1998) (RMSE = 0.20 g cm–3) and PTF-F in Benites et al. (2007) (RMSE = 0.17 g cm–3). Our proposed PTFs use textural fractions and organic carbon as predictors in a hierarchical form. The proposed PTF-4, which uses fine sand, coarse sand, clay, and organic carbon, presented the lowest value for RMSE (0.14 g cm–3) for BD prediction.
  • A practical method to account for outliers in simple linear regression using the median of slopes Note

    Tedeschi, Luis O.; Galyean, Michael L.

    Resumo em Inglês:

    ABSTRACT The ordinary least squares (OLS) can be affected by errors associated with heteroscedasticity and outliers, and extreme points can influence the regression parameters. Methods based on the median rather than on the mean and variance are more resistant to outliers and extreme points. These methods could be used to obtain regression parameter estimates that reflect more accurately the genuine relationship between the Y and X variables, leading to better identification of outliers and extreme points by comparing the slopes and intercepts of both methods. The Theil-Sen (TS) regression computes all possible pairwise slopes and determines the median of slopes as the regression slope. Here, we illustrated the potential use of TS and frequently used robust regression (RR) techniques to single linear regression using synthetic datasets and a practical problem in animal science. Three synthetic datasets were created assuming the normal distribution of Y and X values: one was free of outliers, while the other two had one or two clusters of outliers but the same X values. The TS, OLS, and RR had nearly identical regression parameter estimates for the dataset without synthetic outliers. However, the intercept and slope estimates by the OLS method differed considerably from the TS and RR methods when one or two clusters of outliers were included. The TS approach could be used to indirectly determine the presence of outliers or extreme points by comparing the 95 % confidence interval of the TS and OLS parameter estimates.
  • Soil organic phosphorus in Eucalyptus plantations, Brazil: extraction methods Note

    Alvarenga, Laís Chierici Bernardes Rinaldi; Costa, Marlon Gomes da; Gama-Rodrigues, Antonio Carlos; Aleixo, Seldon; Gama-Rodrigues, Emanuela Forestieri; Gonçalves, José Leonardo de Moraes

    Resumo em Inglês:

    ABSTRACT In-depth knowledge of total soil organic phosphorus (TPO) as a potential P source for plants allows for a comprehensive understanding of the adoption of an efficient management system of phosphorus fertilization in forest plantations. Thus, we aimed to compare three TPO extraction methods (Hedley; Bowman; Bowman and Moir) in different Eucalyptus plantations on strongly weathered soils. The TPO concentrations obtained by the “Hedley” (mean of 130 mg kg–1), and “Bowman and Moir” methods (mean of 131 mg kg–1) were similar. The “Bowman” method extracted less than 50 % of the TPO content extracted by the other methods. Both “Hedley” and “Bowman and Moir” methods showed similar TPO extraction efficiency compared to TP determined by acid digestion. However, the “Hedley” method is the most expensive and time-consuming analytical technique. In view of this, the NaOH+Na2EDTA extractor (Bowman and Moir) would be the most suitable since, in addition to showing high extraction efficiency, it offers fast analysis execution, low analytical error, and lower cost.
  • First occurrence of bidens mottle virus in Brazil: biological and molecular characterization of isolates infecting Zinnia sp. and Bidens pilosa Note

    Favara, Gabriel Madoglio; Ferro, Camila Geovana; Bello, Vinicius Henrique; Oliveira, Felipe Franco de; Kraide, Heron Delgado; Ribeiro Junior, Marcos Roberto; Krause-Sakate, Renate; Kitajima, Elliot Watanabe; Rezende, Jorge Alberto Marques

    Resumo em Inglês:

    ABSTRACT Zinnia sp. and hairy beggartick (Bidens pilosa) plants exhibiting symptoms of possible virus infection were found in the municipality of Santa Bárbara d’Oeste, São Paulo State, Brazil. Flexuous filamentous particles and cytoplasmatic inclusions typical of potyvirus infection were observed by transmission electron microscopy, respectively, in leaf extracts and cells of symptomatic leaves. Infection of both plants with bidens mottle virus (BiMoV) was confirmed by RT-PCR using potyvirus universal primers, followed by nucleotide sequencing of the amplicons. The nearly complete genome sequence of the Brazilian isolate, named BiMoV-BR, is 9700 nucleotides long and shares 95.6 % identity with the corresponding nucleotide sequence of a BiMoV isolate from the United States. BiMoV-BR was mechanically transmitted and caused systemic infection on plants of Zinnia sp., hairy beggarstick, sunflower (Helianthus annuus), and lettuce (Lactuca sativa). Myzus persicae transmitted the virus to Zinnia sp. plants with efficacy of 8 % and 42 %, using one and ten aphids per plant, respectively. This is the first detection of BiMoV in Brazil. Further studies are necessary to evaluate the distribution of this potyvirus in the country.
  • Advances in methodologies to assess wind actions in plastic-covered greenhouses Review

    Soriano, Julio; Shiguemoto, Ana Carolina Gigli; Vieira Neto, José Gabriel

    Resumo em Inglês:

    ABSTRACT The technology provided by greenhouses is essential for protecting crops sensitive to bioclimatic adversities and for improving agricultural production indexes. However, the need to know the exact interaction between the flexible coating and the structure under wind action has motivated new studies. The objective was to perform an in-depth review of the scientific and technological advances regarding methodologies to obtain parameters related to wind actions that are essential for the structural safety of greenhouses. This study showed the relevance of experimental methods; however, the limitations of the study are diverse, as field experiments require the construction and modifications of a prototype, which demand time and financial resources. Experiments in wind tunnels with models on a reduced scale have contributed significantly, as it allows to control the wind flow; however, in plastic-covered greenhouses, discrepancies occur due to the impossibility to represent the aeroelasticity of the construction. Modeling via computational fluid dynamics (CFD) has proven to be a solution for extrapolating limitations in experimental methods by facilitating changes in the construction model and wind flow. In addition to pure turbulence models, studies on hybrid turbulence models (Scale-Resolving Simulation) must be deepened to obtain greater accuracy of pressure coefficients. The complexity of the subject and the need for new contributions to plastic-covered greenhouse projects are a reality, which outlines a promising horizon for research development in the rural construction sector.
  • Agronomic practices toward coffee sustainability. A review Review

    Martinez, Herminia Emilia Prieto; Andrade, Sara Adrián López de; Santos, Ricardo Henrique Silva; Baptistella, João Leonardo Corte; Mazzafera, Paulo

    Resumo em Inglês:

    ABSTRACT The coffee sector is estimated to have a retail market value in excess of USD 83 billion, and over 125 million jobs have been created in the global coffee chain. The coffee specialty market has recently increased significantly, generating opportunities to certify coffee beans produced by sustainable practices. This avoids practices potentially harmful to the environment. Agroforestry, organic farming, intercropping, and soil conservation strategies are examples of sustainable alternatives in the production of coffee. In this review, we focus on practices for the sustainable management of coffee plantations that can help farmers fight problems caused by global warming. More specifically, we address soil organic matter and microbiota, the use of Urochloa grass as intercrop in coffee plantations, shading systems (including agroforestry), and organic coffee production. We concluded that from the agronomic viewpoint, we already have production techniques that can replace traditional ones with significant advantages accruing to the quality of coffee orchard ecosystems. Nevertheless, we need scientific research efforts to deal with the existing gaps and the engagement of the whole coffee chain as a means of guaranteeing an adequate profit to those smallholders who adopt and maintain sustainable practice and are capable of bringing several positive changes to the coffee crop, including the use of microbia-based commercial products and new organic sources of nutrients to complement chemical fertilizers and improve coffee quality.
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