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Search Results: 1 - 10 of 8354 matches for " Carolina;Corá "
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Bulk density and relationship air/water of horticultural substrate
Fernandes, Carolina;Corá, José Eduardo;
Scientia Agricola , 2004, DOI: 10.1590/S0103-90162004000400015
Abstract: change on substrate bulk density during the growing period may negatively affect other substrate physical properties and, consequently, plant growth. the objectives of this research were 1) to characterize physical properties of two horticultural substrates (s1 and s2), 2) to evaluate the effect of different bulk densities values of those substrates on their air/water relationship, and 3) to develop mathematical functions to estimate the air/water relationship by increasing substrates bulk density value. first, the distribution of particles size, the bulk density, and the water release curve of the substrates were determined. then, substrates were packed with three different bulk density values, i.e. 10% (d1), 20% (d2) and 30% (d3), higher than the bulk density (d) determined in the characterization phase. the water release curves were determined for each bulk density value of both substrates. the effect of increasing substrate bulk density in the total porosity (tp), aeration space (as), available water (aw), easily available water (eaw), buffering water (bw), and in the remaining water (rw) was evaluated using simple linear regression and polynomial analysis. the particles size distribution and the water release curves were significantly different for the two substrates. increasing the bulk density value decreased tp and as, and increased bw and rw. the highest values of aw and eaw were observed for d1. regression equations obtained can be used to choose the more appropriate air/water relationship for each growing condition.
Soil sampling intensity and spatial distribution pattern of soils attributes and corn yield in no-tillage system
Rodrigues, Marcos S.;Corá, José E.;Fernandes, Carolina;
Engenharia Agrícola , 2012, DOI: 10.1590/S0100-69162012000500005
Abstract: taking into account that the sampling intensity of soil attributes is a determining factor for applying of concepts of precision agriculture, this study aims to determine the spatial distribution pattern of soil attributes and corn yield at four soil sampling intensities and verify how sampling intensity affects cause-effect relationship between soil attributes and corn yield. a 100-referenced point sample grid was imposed on the experimental site. thus, each sampling cell encompassed an area of 45 m2 and was composed of five 10-m long crop rows, where referenced points were considered the center of the cell. samples were taken from at 0 to 0.1 m and 0.1 to 0.2 m depths. soil chemical attributes and clay content were evaluated. sampling intensities were established by initial 100-point sampling, resulting data sets of 100; 75; 50 and 25 points. the data were submitted to descriptive statistical and geostatistics analyses. the best sampling intensity to know the spatial distribution pattern was dependent on the soil attribute being studied. the attributes p and k+ content showed higher spatial variability; while the clay content, ca2+, mg2+ and base saturation values (v) showed lesser spatial variability. the spatial distribution pattern of clay content and v at the 100-point sampling were the ones which best explained the spatial distribution pattern of corn yield.
Classifica??o de tomate-cereja em fun??o do tamanho e peso dos frutos
Fernandes, Carolina;Corá, José Eduardo;Braz, Leila T.;
Horticultura Brasileira , 2007, DOI: 10.1590/S0102-05362007000200029
Abstract: the purpose of this experiment was to propose a grading system for cherry tomatoes based on fruit size and weight. the experiment was carried out at jaboticabal, s?o paulo state, brazil. fruits of cherry tomatoes, cultivar sindy, harvested out of 60 plants grown in a greenhouse were evaluated. to separate fruits of different sizes, a five plastic box system developed. in this system, the bottom of four boxes drilled with holes of 20; 25; 30, and 35 mm of diameter. the fifth box had no holes and was used as a collector box. fruits retained in each of the boxes were counted and weighed. the average weight of the fruits was calculated for each class size. fruit frequency in each class varied during the harvest period. the percentage of fruits was as follows: 5% of giant fruits, 22% of large fruits, 42% of medium fruits, 20% for small fruits, and 11% of discard. there was a linear correlation between the fruit weight (w) and diameter (d) (w = 1.05 d - 14.71, r** = 0.99, p<0.01). the system used was efficient for grading cherry tomatoes by means of associating fruit diameter and weight. in addition, it was practical and simple.
Altera??es nas propriedades físicas de substratos para cultivo de tomate cereja, em fun??o de sua reutiliza??o
Fernandes, Carolina;Corá, José Eduardo;Braz, Leila T;
Horticultura Brasileira , 2006, DOI: 10.1590/S0102-05362006000100019
Abstract: the objective of this work was to evaluate the effects of the reutilization on the physical properties of different types of substrate used to grow cherry tomato, at jaboticabal, s?o paulo state, brazil (21o14'05" s, 48o17'09" w). we used the split-plot experimental design with complete randomized blocks and four replications. in the plots were placed seven types of substrates, and in the subplots, three periods of physical characterization of the substrates. the seven substrates were prepared with different combinations of three materials: sand, crushed sugarcane and peanut bark. the physical properties evaluated were submitted to variance analysis and the averages were compared by the tukey test, at 5% probability level. the reutilization of the substrate prepared with equal parts of the three components promoted the increase of bulk density and easily available water content, and the decrease of total porosity, aeration space, and remaining water content.
Desempenho de substratos no cultivo do tomateiro do grupo cereja
Fernandes, Carolina;Corá, José Eduardo;Braz, Leila T;
Horticultura Brasileira , 2006, DOI: 10.1590/S0102-05362006000100009
Abstract: cherry tomato growth was evaluated using substrates composed of sand, crushed sugar cane and peanut bark, in jaboticabal, s?o paulo state, brazil. the experimental design was the complete randomized block with seven substrates and four replications. the seven substrates were made up of different combinations of sand (s), crushed sugar cane (csc) and peanut bark (pb): s1 = s; s2 = 2/3 s + 1/3 csc; s3 = 2/3 s + 1/3 pb; s4 = 2/3 s + 1/6 csc + 1/6 pb; s5 = 1/2 s + 1/2 csc; s6 = 1/2 s + 1/2 pb e s7 = 1/3 s + 1/3 csc + 1/3 pb. the evaluated parameters were submitted to a variance analysis and averages were compared by the tukey test, at 5% probability level. the bulk density (bd), aeration space (as) and easily available water (eaw) values were different. bulk density ranged from 790 to 1604 kg m-3; as, from 2 to 21%; and eaw, from 14 to 25%. no difference was observed among the cherry tomato yield obtained from the different substrates, which varied from 8.5 to 10.7 kg m-2. both crushed sugar cane and peanut bark can be used to compose the substrates based on sand for the cherry tomato growth.
Impacto de quatro substratos e parcelamento da fertirriga??o na produ??o de tomate sob cultivo protegido
Fernandes, Carolina;Araújo, Jairo A. C.;Corá, José E.;
Horticultura Brasileira , 2002, DOI: 10.1590/S0102-05362002000400010
Abstract: the experiment was carried out at the unesp in jaboticabal (brazil). the tomato, long-life hybrid cv. carmen, was grown in four substrates with fertigation applied weekly and twice a week in greenhouse conditions. the experimental design was a complete randomized block, with a factorial array of 4 x 2 (four substrates and two forms of fertigation), with four replications. the substrates used were: s1 = fine sand (0.250 - 0.105 mm); s2 = 1/2 fine sand + 1/2 crushed sugar-cane; s3 = 1/2 fine sand + 1/2 ground peanut bark (screened by 7 x 18 mm); s4 = 1/3 fine sand + 1/3 crushed sugar-cane + 1/3 ground peanut bark. the fertigations were: f1 = total amount of nutrients applied, once a week and f2 = half of the total amount applied twice a week. the amount of nutrients, in mg l-1, were: 200 of nitrogen, 60 of phosphorus, 350 of potassium, 206 of calcium, 60 of magnesium, 150 of sulphur, 0.50 of boron, 0.10 of copper, 2 of iron, 0.75 of manganese, 0.10 of zinc and 0.01 of molybdenum. the hydric dotation was realized based upon water evaporation in a class a pan, located at the center of the greenhouse. plant height, number of bunches and fruits per plant, fruit weight and yield per plant were measured. the data were submitted to the variance analysis and the averages were compared by the test of tukey, at the level of 5% of probability. the highest yield was obtained when the fertigation was applied twice a week. the results showed that the substrates s1, s3 and s4 can be used for tomate growth in greenhouse conditions.
Spatial relationships between soil attributes and corn yield in no-tillage system
Rodrigues, Marcos Sales;Corá, José Eduardo;Fernandes, Carolina;
Revista Brasileira de Ciência do Solo , 2012, DOI: 10.1590/S0100-06832012000200029
Abstract: soil properties play an important role in spatial variability of crop yield. however, a low spatial correlation has generally been observed between maps of crop yield and of soil properties. the objectives of the present investigation were to assess the spatial pattern variability of soil properties and of corn yield at the same sampling intensity, and evaluate its cause-and-effect relationships. the experimental site was structured in a grid of 100 referenced points, spaced at 10 m intervals along four parallel 250 m long rows spaced 4.5 m apart. thus, points formed a rectangle containing four columns and 25 rows. therefore, each sampling cell encompassed an area of 45 m2 and consisted of five 10 m long crop rows, in which the referenced points represented the center. samples were taken from the layers 0-0.1 m and 0.1-0.2 m. soil physical and chemical properties were evaluated. statistical analyses consisted of data description and geostatistics. the spatial dependence of corn yield and soil properties was confirmed. the hypothesis of this study was confirmed, i.e., when sampling the soil to determine the values of soil characteristics at similar to sampling intensity as for crop yield assessments, correlations between the spatial distribution of soil characteristics and crop yield were observed. the spatial distribution pattern of soil properties explained 65 % of the spatial distribution pattern of corn yield. the spatial distribution pattern of clay content and percentage of soil base saturation explained most of the spatial distribution pattern of corn yield.
Soil uses in the sugarcane fallow period to improve chemical and physical properties of two latosols (oxisols)
Fernandes, Carolina;Corá, José Eduardo;Marcelo, Adolfo Valente;
Revista Brasileira de Ciência do Solo , 2012, DOI: 10.1590/S0100-06832012000100029
Abstract: sugarcane production should be integrated with crop diversification with a view to competitive and sustainable results in economic, social and environmental aspects. the purpose of this study was to assess the influence of different soil uses during the sugarcane fallow period on the chemical and physical properties of eutroferric red latosol - lvef (oxisol) and acric latosol - lvw (acric oxisol), in jaboticabal, s?o paulo state, brazil (21o14'05'' s, 48o17'09'' w, 600 m asl). a randomized block design was used with five replications and four treatments, consisting of different soil uses (crops) in the sugarcane fallow period: soybean only, soybean/fallow/soybean, soybean/millet/soybean, and soybean/sunn hemp/soybean. after two soybean crops, the lvef chemical properties remained at intermediate to high levels; while those of the lvw, classified as intermediate to high in the beginning, increased to high levels. thus, the different soil uses during the sugarcane fallow period allowed the maintenance of lvef fertility levels and the improvement of those of the lvw. two soybean crops increased macroporosity in the 0.0-0.1 m layer of the lvef; reduced soil aggregates in the 0.0-0.1 and 0.1-0.2 m layers of both soils, and reduced aggregate stability in these two layers of the lvw. planting pearl millet or sunn hemp between the two soybean growing seasons promoted the formation of larger soil aggregates in the surface layer (0.0-0.1 m) of the lvw.
Reuse of sand, crushed sugarcane and peanut hull-based substrates for cherry tomato cultivation
Fernandes, Carolina;Corá, José Eduardo;Braz, Leila Trevizan;
Scientia Agricola , 2007, DOI: 10.1590/S0103-90162007000600011
Abstract: the reuse of substrates for more than one growing season is an alternative to reduce production costs. the objective of this work was to evaluate the yield and quality fruits of the cherry tomato (lycopersicon esculentum) grown in reused substrates. the experimental design was a complete randomized block, with a factorial array of 7 × 2 (seven substrates and two growth periods), with four replications. the seven substrates consisted of different combinations of sand (s), crushed sugarcane (cs) and peanut hull (ph). the substrates used were: s1 = s; s2 = [(2/3 s) + (1/3 cs)]; s3 = [(2/3 s) + (1/3 ph)]; s4 = [(2/3 s) + (1/6 cs) + (1/6 ph)]; s5 = [(1/2 s) + (1/2 cs)]; s6 = [(1/2 s) + (1/2 ph)] and s7 = [(1/3 s) + (1/3 cs) + (1/3 ph)]. these substrates were tested as new (one growth season), and reused (two sequentially growth seasons). the cherry tomato average yield was 9.07 kg m-2 when growth on the new substrates, and 8.44 kg m-2 when growth on the reused ones. the fruit quality was not affected by the reutilization of the substrates. the average values were 6.5 obrix for total soluble solids; 0.6 g for citric acid per 100 g for total titratable acidity and 4.2 for ph. a substrate consisting of equal parts of the three components can be recommended as a good growth medium for cherry tomato. all the substrates tested can be efficiently reused, at least once.
Impacto de quatro substratos e parcelamento da fertirriga o na produ o de tomate sob cultivo protegido
Fernandes Carolina,Araújo Jairo A. C.,Corá José E.
Horticultura Brasileira , 2002,
Abstract: Analisou-se a produ o do tomateiro, híbrido longa vida Carmen, cultivado em quatro substratos, com fertirriga o semanal e duas vezes por semana. O delineamento experimental utilizado foi blocos casualizados, em esquema fatorial 4 x 2 (quatro substratos e duas formas de fertirriga o), em quatro repeti es. Os substratos testados foram: S1 = areia fina (0,250 - 0,105 mm); S2 = 1/2 areia fina + 1/2 baga o de cana-de-a úcar; S3 = 1/2 areia fina + 1/2 casca de amendoim moída (passada em peneira com abertura de 7 x 18 mm) e S4 = 1/3 areia fina + 1/3 baga o de cana-de-a úcar + 1/3 casca de amendoim moída. As fertirriga es avaliadas foram: F1 = fertirriga o realizada uma vez por semana, com aplica o da quantidade total de nutrientes e, F2 = fertirriga o realizada duas vezes por semana, com aplica o da metade da quantidade total de nutrientes, demandada por semana, em cada vez. A quantidade de nutrientes, em mg L-1, fornecida por meio de fertirriga o, foi: 200 de nitrogênio, 60 de fósforo, 350 de potássio, 206 de cálcio, 60 de magnésio, 150 de enxofre, 0,50 de boro, 0,10 de cobre, 2 de ferro, 0,75 de manganês, 0,10 de zinco e 0,01 de molibdênio. A dota o hídrica foi realizada em fun o dos dados obtidos em um tanque classe A, localizado no centro da casa de vegeta o. Avaliou-se a altura das plantas, o número de cachos e de frutos por planta, o peso individual do fruto e a produ o por planta. Os dados foram submetidos à análise de variancia e as médias foram comparadas pelo teste de Tukey, ao nível de 5% de probabilidade. Verificou-se que a fertirriga o realizada duas vezes por semana, suprindo a demanda total de nutrientes da semana, resultou em consideráveis melhorias de produ o. Os substratos utilizados, com exce o do substrato S2, apresentaram potencial de uso para o cultivo do tomateiro em ambiente protegido.
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