Soil Physical Quality and Soybean Yield as Affected by Chiseling and Subsoiling of a No-Till Soil
13/abr/2016
ABSTRACT The concept of soil physical quality (SPQ) is currently under discussion, and an agreement about which soil physical properties should be included in the SPQ characterization has not been reached. The objectives of this study were to evaluate the ability of SPQ indicators based on static and dynamic soil properties to assess the effects of two loosening treatments (chisel plowing to 0.20 m [ChT] and subsoiling to 0.35 m [DL]) on a soil under NT and to compare the […]
Sampling Position under No-Tillage System Affects the Results of Soil Physical Properties
13/abr/2016
ABSTRACT Understanding the spatial behavior of soil physical properties under no-tillage system (NT) is required for the adoption and maintenance of a sustainable soil management system. The aims of this study were to quantify soil bulk density (BD), porosity in the soil macropore domain (PORp) and in the soil matrix domain (PORm), air capacity in the soil matrix (ACm), field capacity (FC), and soil water storage capacity (FC/TP) in the row (R), interrow (IR), and intermediate position between R and […]
Physical Properties of a Hapludox after Three Decades under Different Soil Management Systems
12/abr/2016
ABSTRACT Changes in soil physical properties due to different management systems occur slowly, and long-term studies are needed to assess soil quality. The objectives of this study were to evaluate the effects of soil management systems and liming methods on the physical properties of a Latossolo Bruno Alumínico típico (Hapludox). A long-term experiment that began in 1978 with conventional and no-tillage systems was assessed. In addition, different liming methods (no lime, incorporated lime, and lime on the soil surface) have […]
Diagnosis of the Nutritional Status of Garlic Crops
12/abr/2016
ABSTRACT Univariate methods for diagnosing nutritional status such as the sufficiency range and the critical level for garlic crops are very susceptible to the effects of dilution and accumulation of nutrients. Therefore, this study aimed to establish bivariate and multivariate norms for this crop using the Diagnosis and Recommendation Integrated System (DRIS) and Nutritional Composition Diagnosis (CND), respectively. The criteria used were nutritional status and the sufficiency range, and then the diagnoses were compared. The study was performed in the […]
Phosphorus Forms in Ultisol Submitted to Burning and Trituration of Vegetation in Eastern Amazon
06/abr/2016
ABSTRACT The use of fire to prepare agricultural areas is a technique still used by small farmers in eastern Amazon. This type of management changes the dynamics of soil nutrients, especially phosphorus, which constitutes the most limiting nutrient for crop production in tropical soils. This study was carried out to evaluate changes in phosphorus forms in an Argissolo Amarelo Distrófico (Ultisol) submitted to burning and trituration of secondary forest in eastern Amazon. The evaluated systems were: slash-and-burn of vegetation; slash-and-mulch […]
Organic and Nitrogen Fertilization of Soil under ‘Syrah’ Grapevine: Effects on Soil Chemical Properties and Nitrate Concentration
06/abr/2016
ABSTRACT Viticulture is an activity of great social and economic importance in the lower-middle region of the São Francisco River valley in northeastern Brazil. In this region, the fertility of soils under vineyards is generally poor. To assess the effects of organic and nitrogen fertilization on chemical properties and nitrate concentrations in an Argissolo Vermelho-Amarelo (Typic Plinthustalf), a field experiment was carried out in Petrolina, Pernambuco, on Syrah grapevines. Treatments consisted of two rates of organic fertilizer (0 and 30 […]
Changes in Soil Organic Carbon Fractions in Response to Cover Crops in an Orange Orchard
06/abr/2016
ABSTRACT The cultivation of cover crops intercropped with fruit trees is an alternative to maintain mulch cover between plant rows and increase soil organic carbon (C) stocks. The objective of this study was to evaluate changes in soil total organic C content and labile organic matter fractions in response to cover crop cultivation in an orange orchard. The experiment was performed in the state of Bahia, in a citrus orchard with cultivar ‘Pera’ orange (Citrus sinensis) at a spacing of […]
Potential of Spectroradiometry to Classify Soil Clay Content
06/abr/2016
ABSTRACT Diffuse reflectance spectroscopy (DRS) is a fast and cheap alternative for soil clay, but needs further investigation to assess the scope of application. The purpose of the study was to develop a linear regression model to predict clay content from DRS data, to classify the soils into three textural classes, similar to those defined by a regulation of the Brazilian Ministry of Agriculture, Livestock and Food Supply. The DRS data of 412 soil samples, from the 0.0-0.5 m layer, […]
Characterization of Ornamental Rock Residue and Potassium Liberation Via Organic Acid Application
06/abr/2016
ABSTRACT Organic acids present in organic matter and, or, exudates by microorganisms and plants can increase the liberation of potassium present in minerals. The objective of this study was to characterize the residue from ornamental rocks and evaluate the release of K from these residues after the application of organic acids. The experiment was conducted under laboratory conditions and followed a 2 × 3 × 5 factorial design with three replicates. The studied factors were: two organic acids (citric acid […]
MANEJO DA IRRIGAÇÃO E FERTILIZANTES NITROGENADOS PARA REDUZIR A VOLATILIZAÇÃO DE AMÔNIA
01/dez/2015
RESUMO A redução das perdas de nitrogênio pela volatilização de amônia (NH3) pode ser alcançada pelo manejo adequado da irrigação, bem como pelo uso de fontes de N alternativas à ureia comum. A eficiência desses fatores em reduzir a volatilização de NH3 foi avaliada em experimento conduzido num Argissolo Vermelho Distrófico típico cultivado por 28 anos no sistema aveia-preta/milho (inverno/verão) em plantio direto na Depressão Central do RS. O delineamento experimental foi de blocos casualizados com parcelas subdivididas, em três […]