The Proctor test is time-consuming and requires sampling of several kilograms of soil. Proctor test parameters were predicted in Mollisols, Entisols and Vertisols of the Pampean region of Argentina under different management systems. They were estimated from a minimum number of readily available soil properties (soil texture, total organic C) and management (training data set; n = 73). The results were used to generate a soil compaction susceptibility model, which was subsequently validated using a second group of independent data (test data […]

The increased availability of soil water is important for the management of non-irrigated orange orchards. The objective of this study was to evaluate the availability of soil water in a Haplorthox (Rhodic Ferralsol) under different tillage systems used for orchard plantation, mulch management and rootstocks in a “Pêra” orange orchard in northwest Paraná, Brazil. An experiment in a split-split-plot design was established in 2002, in an area cultivated with Brachiaria brizantha grass in which three tillage systems (no tillage, conventional […]

The technique of TDR (time-domain reflectometry) is an important tool for the study of soil water content. For a correct use of this technique, models that relate the volumetric water content in soil with the soil dielectric constant must be calibrated, considering the characteristics of each soil. The purpose of this study was to evaluate the influence of soil type and sampling form (disturbed and undisturbed samples) on the dielectric constant (Ka) of the soil and the performance of models […]

The presence of highly stable microaggregates can hamper soil dispersion in some Oxisols. These very clayey groupings may be not completely disaggregated by chemical and mechanical dispersion. Due to their size, the silt proportion of the soil is overestimated. A laboratory experiment was conducted to verify the use of the solution equilibrium P (SEP) to evaluate the response to particle size analysis pre-treatments in Oxisols. The treatments were arranged in a 7 x 22 factorial design, in randomized blocks with […]

Different agricultural practices accomplish distinct controls on microbial C an N dynamics. The dynamics of microbial C and N in soils under no-tillage system (NT) were evaluated in the crop sequences corn/wheat/soybean and soybean/wheat/soybean in soils with different texture, areas and periods under NT at the “Santa Branca” farm, Tibagi, Paraná State, Brazil (50 ° 23 ‘ W, 24 ° 36 ‘ N). The experiment was installed at four sites, three of which had been NT cultivated in the previous 12 years, with the following textures: clay (PD12-TmuA); sandy-clay […]

The soil particle-size distribution has great influence on the plant yield. In the 2002/2003 growing season, plant and soil attributes of an experimental station of the Faculdade de Engenharia/UNESP (Ilha Solteira/SP – Brazil) were analyzed: common bean grain yield (GP), straw yield (SP), clay content (CL), silt (SI) and sand (SA) of a Red Latosol (Oxisol) under no-tillage. The objective was to analyze the variability of the evaluated attributes to characterize spatial dependences and to study linear and spatial correlations […]

The northwestern region of Mato Grosso State consists of complex landscapes due to ongoing geomorphologic activity that contributes to the occurrence of different soil classes over small distances, which complicates soil sampling strategies. This study was conducted in Juruena (MT), with the objective of identifying pedologic classes in undisturbed forested headwater catchments by examining the spatial variability of soil texture and color, and taking elevation and topographic position into consideration. The spatial variability of soil texture and color were determined […]

The objective of this experiment was to quantify variations in maize canopy of plants submitted to two water managements (irrigated and terminal soil water deficit) in clayey, loamy and sandy soils. The experiment was conducted at the experimental area of the Rural Engineering Department of the Federal University of Santa Maria during the 1995/1996 growing season. A set of 12 drainage lysimeters was used. These were 156 cm long, 100 cm wide and 80 cm deep and were placed under a shelter to avoid […]

The objectives of this experiment were to identify differences in the total quantity of water stored in soil, storing capacity of water available to the plants and in the water consumption of maize plants cultivated in soils of different textures. The experiment was conducted at the experimental area of the Rural Engineering Department of the Federal University of Santa Maria during the 1995/1996 growing season. A set of 12 drainage lysimeters was used. These were 156 cm long, 100 cm wide and 80 cm […]