3290 results

Nutrient uptake and yield of common bean fertilized with poultry litters and mineral nutrients

Késia Silva Lourenço, Juliano Corulli Corrêa, Paulo Roberto Ernani, Letícia dos Santos Lopes, Rodrigo da Silveira Nicoloso

01/Apr/2013

Common bean is traditionally grown on small farms in Brazil, where animal wastes are often used as soil fertilizer. Since this is a short-cycle species, nutrients must be available soon after seed germination, which is not always the case when supplied in the form of organic fertilizers. This study was carried out to evaluate the efficiency of different poultry litters in comparison with mineral fertilizers to increase dry matter yield and nutrient release to beans. The experiment was conducted in […]

Rainfall erosivity associated to return periods and occurrence probability in the state of rio de janeiro, brazil

Roriz Luciano Machado, Daniel Fonseca de Carvalho, Janaina Ribeiro Costa Rouws, Daniela Pinto Gomes, Eliete Nazare Eduardo

01/Apr/2013

Knowledge on rainfall erosivity associated to occurrence probability and return periods can contribute to conservation planning in the medium and long term. With the objective of generating information for a better use of medium and long-term erosion models and erosion control, rainfall data of 30 pluviometric and pluviographic data sets from 25 cities ranging from 1933 to 2006 were studied in terms of adjustment of data sets, calculation of the probability of theoretical occurrence (P) and return period (T) of […]

Effect of phosphite-phosphate interaction on growth and on phosphorus nutrition of common bean in nutrient solution

Josinaldo Lopes Araújo, Valdemar Faquin, Fabrício William de Ávila, Thiago Queiroz Pedroso

01/Apr/2013

The use of phosphite as a fungicide or supplementary source of phosphorus (P) has been intensified in recent years, however, little is known about its effects on important crops such as common bean. This work aimed to evaluate the effect of phosphite on growth and phosphate nutrition of bean plants. Two experiments in an completely randomized design were conducted in nutrient solution in a green house, from January to March 2008. In the first experiment, the treatments consisted of a […]

Lead and zinc in the structure of organic and mineral soil components

Larissa Kummer, Vander de Freitas Melo, Yara Jurema Barros

01/Apr/2013

In addition to the more reactive forms, metals can occur in the structure of minerals, and the sum of all these forms defines their total contents in different soil fractions. The isomorphic substitution of heavy metals for example alters the dimensions of the unit cell and mineral size. This study proposed a method of chemical fractionation of heavy metals, using more powerful extraction methods, to remove the organic and different mineral phases completely. Soil samples were taken from eight soil […]

Water erosion in no-tillage monoculture and intercropped systems along contour lines

Ildegardis Bertol, Roger Robert Ramos, Fabrício Tondello Barbosa, Antonio Paz González, Julio César Ramos, Douglas Henrique Bandeira

01/Apr/2013

Water erosion is the major cause of soil and water losses and the main factor of degradation of agricultural areas. The objective of this work was to quantify pluvial water erosion from an untilled soil with crop rows along the contour, in 2009 and 2010, on a Humic Dystrupept, with the following treatments: a) maize monoculture; b) soybean monoculture; c) common bean monoculture; d) intercropped maize and bean, exposed to four simulated rainfall tests of on hour at controlled intensity […]

Forms of lime application, cover crops and nitrogen rates in maize

Aguinaldo José Freitas Leal, Edson Lazarini, Leandro Rebuá Rodrigues, Luiz Henrique Marcandalli

01/Apr/2013

The no-tillage (NT) management is widely used in the Cerrado region, but some questions remain unanswered, for example about the need of liming and adequate nitrogen rates for commercial crops when preceded by cover crops. Our objective was to evaluate the effect of precedent cover crops on the maize demand for nitrogen fertilization and forms of liming preceding the adoption of no-tillage management (NT) in different growing seasons. The experiment was arranged in a randomized block factorial design 5 x […]

An appropriate data set size for digital soil mapping in Erechim, Rio Grande do Sul, Brazil

Alexandre ten Caten, Ricardo Simão Diniz Dalmolin, Fabrício de Araújo Pedron, Luis Fernando Chimelo Ruiz, Carlos Antônio da Silva

01/Apr/2013

Digital information generates the possibility of a high degree of redundancy in the data available for fitting predictive models used for Digital Soil Mapping (DSM). Among these models, the Decision Tree (DT) technique has been increasingly applied due to its capacity of dealing with large datasets. The purpose of this study was to evaluate the impact of the data volume used to generate the DT models on the quality of soil maps. An area of 889.33 km² was chosen in […]

Digital soil mapping by artificial neural networks based on soil-landscape relationships

Gustavo Pais de Arruda, José Alexandre M. Demattê, César da Silva Chagas

01/Apr/2013

Digital mapping techniques can help reduce the lack of soil information in areas where no 1st and 2nd order soil surveys were performed. The aim of this study was to obtain a digital soil map (DSM) by artificial neural networks (ANN) using the correlation between soil mapping units and environmental covariates. The study area of approximately 11,000 ha is located in Barra Bonita, SP, Brazil. Based on a cluster analysis of environmental covariates, five reference areas were chosen for conventional […]

Incubation methods for assessing mineralizable nitrogen in soils under sugarcane

Eduardo Mariano, Paulo Cesar Ocheuze Trivelin, José Marcos Leite, Michele Xavier Vieira Megda, Rafael Otto, Henrique Coutinho Junqueira Franco

01/Apr/2013

Considering nitrogen mineralization (N) of soil organic matter is a key aspect for the efficient management of N fertilizers in agricultural systems. Long-term aerobic incubation is the standard technique for calibrating the chemical extraction methods used to estimate the potentially mineralizable N in soil. However, the technique is laborious, expensive and time-consuming. In this context, the aims of this study were to determine the amount of soil mineralizable N in the 0-60 cm layer and to evaluate the use of […]

Mineralogy of the clay fraction of alfisols in two slope curvatures. IV – spatial correlation with physical properties

Livia Arantes Camargo, José Marques Júnior, Gener Tadeu Pereira

01/Apr/2013

Although the influence of clay mineralogy on soil physical properties has been widely studied, spatial relationships between these features in Alfisols have rarely been examined. The purpose of this work was to relate the clay minerals and physical properties of an Alfisol of sandstone origin in two slope curvatures. The crystallographic properties such as mean crystallite size (MCS) and width at half height (WHH) of hematite, goethite, kaolinite and gibbsite; contents of hematite and goethite; aluminium substitution (AS) and specific […]

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