Studies on the kinetics of K and Mg release improve our understanding of nutrient dynamics in soils and can provide information to adjust fertilization recommendations and increase plant yields. The selected soils represented different parent materials (sandstone – Bauru Group, Granite – Araxá Group, basalt – São Bento Group and sediments – Detritic-Lateritic-Tertiary Cover) and weathering degrees. The total K content in soil and its fractions were determined by HF, HNO3 and H2SO4 digestion. To estimate the potential of clay […]

The critical potassium level for fertilizer recommendation for soils in the State of Rio Grande do Sul (RS) and Santa Catarina (SC) with CEC from 5.1 to 15 cmolc dm-3 is 60 mg dm-3. However, until 2002 concentrations of 80 mg dm-3 had been used. Two experiments were carried out on an experimental area of the Department of Soil Science of the Federal University of Santa Maria (RS-Brazil) on a Sandy Typic Hapludalf under no-tillage. The objective of the study was to evaluate critical potassium levels […]

As the time of adoption of no-tillage systems lengthens thee occur modification in soil physical attributes; however, these effects are not well quantified yet. The present study had the objective to evaluate the effect of time of adoption of a no-tillage system, compared to native forest and a conventional tillage system using physical attributes of a Dystroferric Red Nitosol. The evaluated systems were: PD1 (one year of adoption of no-tillage), PD4 (no-tillage for four years), PD5 (no-tillage for five years), […]

The high spatial variability of the soil hydraulic conductivity as a function of soil water content (or soil-water matric potential) makes the sampling planning and the use or extrapolation of mean values obtained in field studies of soil-water dynamics difficult. In this context, the objective of this study was to verify the temporal stability of soil-water content and soil-water matric potential and to show how the temporal stability methodology can be used as a tool to rationalize the sampling strategy […]

Rill erosion is characterized by concentrated surface water flow, with enough shear stress and detachment capacity to deform the rill and alter flow hydraulics, responsible for rill formation dynamics. The objective of this study was to evaluate flow hydraulic conditions that can provide important information on erosion relationships, soil erodibility and sediment transport in furrows of a recently-tilled Palleudult. Rills were pre-formed in a sandy clay loam soil with an average slope of 0.067 m m-1. Simulated rainfall with an intensity of […]

Adsorption and desorption reactions of metals in soils are influenced by the surface of the soil colloid attributes and solution composition. This study evaluated the effect of the pH on Cd adsorption (Cdads) and desorption (Cddes) in l7 Brazilian Oxisol samples that differed in their chemical, physical and mineralogical attributes. Samples of each soil, suspended in 5 mmol L-1 Ca(NO3)2 (pH adjusted to 4.5; 5.5, and 6.5; ratio soil:solution 1:67) were placed to react with 0.20 mmol L-1 Cd(NO3)2 (final […]

High N concentrations in biosolids are one of the strongest reasons for their agricultural use. However, it is essential to understand the fate of N in soils treated with biosolids for both plant nutrition and managing the environmental risk of NO3–-N leaching. This work aimed at evaluating the risk of NO3–-N leaching from a Spodosol and an Oxisol, each one treated with 0.5-8.0 dry Mg ha-1 of fresh tertiary sewage sludge, composted biosolids, limed biosolids, heat-dried biosolids and solar-irradiated biosolids. Results indicated that […]

Liming alters chemical soil attributes and favors root development, but its efficiency depends on the incorporation form and the physical and chemical characteristics of the soil. This experiment was carried out to evaluate the efficiency of incorporated or surface liming seven years after its application on a Hapludalf under no-tillage system and located in Santa Maria, RS, Brazil. The replicated treatments consisted of four surface lime rates (0.0; 2.0, 8.5 and 17.0 t ha-1), incorporated by one plowing followed by two diskings. […]

Tillage and plant species that compose the soil management and crop rotation systems have a pronounced effect on soil physical quality, especially on aggregate stability. This study aimed to evaluate the degree of aggregate stability of a soil cultivated under reduced tillage (RT) and conventional tillage (CT) using distinct summer cover crops. Two experiments were carried out in Chapecó, State of Santa Catarina, Brazil on a Hapludox under RT (1993-1998) and CT (1994-1998). Five crop systems were evaluated in each […]

The influence of the salt content of two contrasting water sources (river and shallow well) on the hydraulic attributes of a clay loam Fluvic Inceptisol were tested. The experiment was carried out in 2000/2001 agricultural year on a 5,000 m2 plantation of Musa sp banana, cultivar pacovan. It consisted of a 2 x 3 factorial arrangement of two water sources and three irrigation levels (L1, L2 and L3), applied via microsprinkling. Results showed that the different irrigation levels and water quality did not […]