Volume 37, Number 1, 2013

Under field conditions, thermal diffusivity can be estimated from soil temperature data but also from the properties of soil components together with their spatial organization. We aimed to determine soil thermal diffusivity from half-hourly temperature measurements in a Rhodic Kanhapludalf, using three calculation procedures (the amplitude ratio, phase lag and Seemann procedures), as well as from soil component properties, for a comparison of procedures and methods. To determine thermal conductivity for short wave periods (one day), the phase lag method […]

Vegetated slopes are more resistant to mass movement and erosion by water. The vegetation contributes to the soil stability, especially by increasing the shear strength provided by roots. Plant species that have been most effective in stabilizing unstable slopes are the grasses, belonging to the family Gramineae. One specimen of this family, vetiver (Chrysopogon zizanioides (L.) Roberty), has proved very effective in slope stabilization. With the objective of evaluating the improvement of soil shear strength parameters at different times after […]

Soil organic matter (SOM) is one of the major reservoirs of carbon on Earth and is one of the key contributors to the carbon cycle. Peatlands are natural accumulators of organic matter commonly derived from decomposing plant residues in water-saturated environments, and represent an initial stage of a much longer pedogenic pathway leading to carbonification. The soil biomass markedly influences the global carbon cycle, accounting for approximately 85 % of all carbon on the Earth’s surface. Plant tissues are mainly […]

Much of the organic matter of a typical peat consists of humic substances, mainly formed via humification of organic residues, decomposed by soil microorganisms, and by the polymerization of organic compounds to functional macromolecules, which are normally more resistant to degradation. The fundamental pathways governing the humification of soil organic matter (SOM) are not well understood so far, and most available data about the identified chemical precursors of humic substances and the main chemical routes by which they are transformed […]

For rice, few studies use foliar analysis methods developed for local conditions of climate, soil or cultivars. The purpose of this study was to evaluate the methods of Compositional Nutrient Diagnosis and of Mathematical Chance to define nutritional standards for rice fields in Rio Grande do Sul state, Brazil. Data of 356 irrigated rice fields for grain yield and foliar contents (N, P, K, Ca, Mg, S, B, Cu, Fe, Mn, Zn, and Mo) were used to calculate the sufficiency […]

Successive applications of pig slurry to soils under no-tillage can increase the nutrient levels in the uppermost soil layers and part of the nutrients may be transferred to deeper layers. The objective was to evaluate the distribution of nutrients in the profile of a soil after 19 pig slurry applications under no-tillage for 93 months. The experiment was conducted from May 2000 to January 2008 in an experimental area of the Federal University of Santa Maria, southern Brazil, on a […]

One of the largest strawberry-producing municipalities of Rio Grande do Sul (RS) is Turuçu, in the South of the State. The strawberry production system adopted by farmers is similar to that used in other regions in Brazil and in the world. The main difference is related to the soil management, which can change the soil chemical properties during the strawberry cycle. This study had the objective of assessing the spatial and temporal distribution of soil fertility parameters using principal component […]

Aluminum (Al) toxicity is one of the most limiting factors for productivity. This research was carried out to assess the influence of Al nutrient solution on plant height, dry weight and morphoanatomical alterations in corn (Zea mays L.) roots and leaves. The experiment was conducted in a greenhouse with five treatments consisting of Al doses (0, 25, 75, 150, and 300 µmol L-1) and six replications. The solutions were constantly aerated, and the pH was initially adjusted to 4.3. The […]

When conventional tillage is replaced by no-tillage (NT) changes occur in the dynamics of soil nutrients and acidity, which may influence the soil-plant relationships and consequently, the criteria for soil fertility management. This study determined the criteria for liming as well as the soil critical levels for P and K in a crop rotation of soybean, maize, wheat, barley, and white oat, widely used in the South-Central region of the State of Parana, in Southern Brazil. The study involved 13 […]

The use of SMP pH to estimate the potential acidity (H + Al) is more practical than the method of 0.5 mol L-1 calcium acetate for routine laboratory analyses. The objective was to fit an equation to estimate the H + Al from SMP pH values of soils of the State of Pará. From various regions of the state, 177 soil samples were collected, in which the SMP pH was determined in 0.01 mol L-1 CaCl2 solution and H + […]