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37 results

Estimation of the Retention and Availability of Water in Soils of the State of Santa Catarina

Diego Bortolini, Jackson Adriano Albuquerque


ABSTRACT: Soil water retention and availability are important properties for agricultural production, which can be measured directly or estimated by pedotransfer functions. Some studies on this topic were carried out in Santa Catarina, Brazil. To improve the estimates, it is necessary to evaluate other properties, to analyze more soil types, as well as to use other analysis techniques such as artificial neural networks and regression trees. Thus, the objective of the study was to estimate the field capacity (FC), permanent […]

Determining the In Situ Apparent Thermal Diffusivity of a Sandy Soil

Oscar Fernando Silva Aguilar, Jorge Alberto Andaverde Arredondo, Beatris Adriana Escobedo Trujillo, Artemio Jesús Benitez Fundora


ABSTRACT: The thermal wave amplitude method is used to determine soil thermal diffusivity in situ for a sandy soil in Mexico (Coatzacoalcos, Veracruz). Soil diurnal temperature fluctuations were measured from depths of 0.05 to 0.65 m, in 0.01 m increments, during the months of April and August. Five mean diffusivity values were obtained experimentally, corresponding to the different depths combination. The soil thermal diffusivity ranged between 2.26 × 10−7 and 8.71 × 10−7 m2 s−1. The diffusivity values obtained are […]

Soil Water Retention Curve as Affected by Sample Height

Maria Laiane do Nascimento Silva, Paulo Leonel Libardi, Fernando Henrique Setti Gimenes


ABSTRACT: The soil water retention curve is one of the main instruments to assess the soil physical quality and to improve soil management. Traditionally, the equipment most used in the laboratory to determine the retention curve has been Haines funnels and Richards chambers. An important factor to which little attention has been given in the use of these equipaments is the height of the undisturbed soil sample. This work proposes to evaluate the influence of different heights of undisturbed samples […]

An Alert Regarding a Common Misinterpretation of the Van Genuchten α Parameter

Quirijn de Jong van Lier, Everton Alves Rodrigues Pinheiro


ABSTRACT Among the equations available to describe the relation between matric potential and soil water content, the soil water retention function, the most commonly used is the equation proposed by Van Genuchten in his 1980 landmark paper. In soil physics literature, especially in Brazil, several authors relate the inverse of the Van Genuchten parameter α to the air-entry pressure. This study aimed to show this common interpretation to be erroneous, as 1/α corresponds to water contents lower than saturation. The […]

Transpiration Reduction Factor and Soybean Yield in Low Land Soil with Ridge and Chiseling

Paulo Ivonir Gubiani, Eduardo Augusto Müller, André Somavilla, Anderson Luiz Zwirtes, Rodrigo Pivoto Mulazzani, Enio Marchesan


ABSTRACT Water and oxygen deficiencies in the soybean crop cultivated on lowland soils are an important topic of research. The objective of this study was to investigate changes in water and oxygen supply and soybean yield caused by soil management in lowland soils. A soybean crop was grown under four soil conditions: no-tillage (NT), chiseling (CH), ridge tillage on no-tillage (NTR), and ridge tillage on chiseling (CHR). Soil bulk density, total porosity, macro- and microporosity, air permeability, and saturated hydraulic […]

Visual Evaluation of the Soil Structure under Different Management Systems in Lowlands in Southern Brazil

Ivana Kruger Tuchtenhagen, Cláudia Liane Rodrigues de Lima, Adilson Luís Bamberg, Rachel Muylaert Locks Guimarães, Pulido-Moncada Mansonia


ABSTRACT The “Visual Evaluation of Soil Structure” (VESS) is a method used primarily to evaluate the soil structural quality of Oxisols in Brazil and secondly for more specific research, consultancy, and teaching purposes. Since the methodology was never applied and compared with laboratory evaluations of physical properties of hydromorphic soils of the Pampa biome in the south of Brazil, this study evaluated the use of VESS as a visual indicator of the structure quality of a typic eutrophic Albaqualf soil […]

Temporal Variation of Soil Physical Quality under Conventional and No-Till Systems

Carlos Germán Soracco, Luis Alberto Lozano, Rafael Villarreal, Esteban Melani, Guillermo Oliverio Sarli


ABSTRACT: Determination of soil physical quality (SPQ) is very important because it is related to many important soil processes. However, it is not clear which indicators should be considered in this evaluation, and information about temporal variation of SPQ under different soil tillage systems is scarce. The aim of this study was to determine the effects of no tillage (NT) and conventional tillage (CT) on temporal variation of capacity SPQ indicators [bulk density (BD), macroporosity (Pmac), air capacity (AC), plant […]

Hourly, Daily, and Monthly Soil Temperature Fluctuations in a Drought Tolerant Crop

Polianna dos Santos de Farias, Luciano da Silva Souza, Arlicélio de Queiroz Paiva, Áureo Silva de Oliveira, Laércio Duarte Souza, Carlos Alberto da Silva Ledo


ABSTRACT Soil temperature is a physical property of great agricultural importance in the soil-plant relationship and in energy exchange with the atmosphere. This study was conducted in a degraded Cambissolo Háplico Ta Eutrófíco (Cambisol; Inceptisol) in the Irecê Identity Territory, Bahia, Brazil, aiming to evaluate the hourly, daily, and monthly fluctuations of soil temperature at depth, and soil thermal diffusivity in the castor bean crop. Hourly soil temperature data from February 4, 2014, to September 30, 2015, were obtained by […]

Soil CO2 Efflux Measurements by Alkali Absorption and Infrared Gas Analyzer in the Brazilian Semiarid Region

Carlas Renata Prissila Costa Ferreira, Antonio Celso Dantas Antonino, Everardo Valadares de Sá Barreto Sampaio, Karina Guedes Correia, José Romualdo de Sousa Lima, Willames de Albuquerque Soares, [...]


ABSTRACT The CO2 emission from the soil surface, commonly referred to as soil CO2 efflux (ECO2) or soil respiration, is the sum of processes that include root respiration and microbial activity. Measuring this evolution is important to establish sustainable land use models and to estimate global fluxes of carbon, which affect climate change. Despite its importance, few measurements have been made in areas of the semiarid Brazilian Northeast region, and most of them were made using the alkali absorption method […]

Estimating Sample Size of Soil Cone Index Profiles by Bootstrapping

Carlos Agustín Alesso, María Josefina Masola, María Eugenia Carrizo, Silvia Del Carmen Imhoff


ABSTRACT Measurements of the soil cone index are widely used to assess soil resistance to root penetration (SR) and to monitor the soil compaction status of agricultural fields. However, soil sampling for SR estimation is a rather challenging task in view of the high spatial and temporal variability of the soil. This study proposed a bootstrapping method to determine the minimum sample size required to estimate the vertical profile of mean soil cone index (CI) values at different levels of […]

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