Volume 33, Number 4, 2009

Soil quality (SQ) has become a major research issue among soil scientists since the early 1990’s, following the recognition of the role soils play in terms of agricultural sustainability and environmental quality. This review aims to discuss the state of the art concerning soil quality and look into the proposed indicators for its evaluation. Most part of the research work in the literature is focused on the identification of a soil attribute that would serve as a SQ indicator (SQI) […]

The use of animal manure in agricultural systems can cause water contamination and/or pollution by nutrients, especially by consecutive applications to the same area. In view thereof, the purpose of this study was to evaluate the effect of manure and fertilizer application on NH4+, NO3–, P and K leaching. For this evaluation, undisturbed soil columns were collected from a seven-year field experiment that consisted of 12 treatments, resulting from the combinations of four doses of dairy slurry with three doses […]

The ability of a soil to keep its structure under the erosive action of water is usually high in natural conditions and decreases under frequent and intensive cultivation. The effect of five tillage systems (NT = no-till; CP = chisel plowing and one secondary disking; CT = primary and two secondary distings; CTb = CT with crop residue burning; and CTr = CT with removal of crop residues from the field), combined with five nutrient sources (C = control, no […]

The volumetric instability of soils due to changes in the water content is complex and is influenced by several factors, such as soil type, climate conditions and tension state. Vertissols are soils that undergo variations in volume. One of their most important morphological features are slickensides that reflect contraction and fissuring during the drying process, and swelling during wetting. Soils that vary in volume when flooded require special care regardless of their use for agriculture, construction or both. The objective […]

The purpose of this study was to evaluate, under field conditions, in Colina-SP, Brazil, the response of two genetically different corn cultivars to six compaction levels of an Oxisol. The experiment was arranged in a randomized complete block design, with strip plots and four replications. The corn hybrids DKB 390 and DAS 2B710 were used. After corn seeding, non-deformed soil samples were collected from the layers 0-0.10, 0.10-0.20 and 0.20-0.30 m to determine soil physical properties and the S index. At the seed […]

The objective of this study was to evaluate, under field conditions, in Colina-SP, Brazil, the response of two corn cultivars to six soil compaction levels of an Oxisol regarding the root system development, and to characterize soil compaction by the least limiting water range (LLWR). The experiment was arranged in a randomized complete block design, with strip plots and four replications. The corn hybrids DKB 390 and DAS 2B710 were used. After corn sowing, undisturbed soil samples were collected to determine physical […]

In the areas where irrigated rice is grown in the south of Brazil, few studies have been carried out to investigate the spatial variability structure of soil properties and to establish new forms of soil management as well as determine soil corrective and fertilizer applications. In this sense, this study had the objective of evaluating the spatial variability of chemical, physical and biological soil properties in a lowland area under irrigated rice cultivation in the conventional till system. For this […]

Under irrigated agriculture one of the main causes of yield variability, which is the plant-available water, is controlled. In this case, other yield limitations caused by soil attributes become more relevant. To investigate the spatial variability of soil attributes and crop yields, besides the relation between chemical and physical-hydric soil attributes and crop yields of two irrigated commercial plantations (51.8 and 58.2 ha) were studied in Trindade do Sul (TS) and Palmeira das Missões (PM) respectively, in the state of […]

The least limiting water range (LLWR) integrates the plant growth factors and the critical bulk density is an indicator of the soil structural quality. The objective of this study was to determine the LLWR of a clayey Oxisol. Soil samples with preserved structure were collected in an experiment with three levels of soil compaction: NT – continuous no-tillage for six years, NTc – no-tillage with additional compaction and Chi – chisel plowing on previous no-till soil. To determine soil penetration […]

Organic matter dynamics and nutrient availability in saline agricultural soils of the State of Guanajuato might provide information for remediation strategies. 14C labeled glucose with or without 200 mg kg-1 of NH4+-N soil was added to two clayey agricultural soils with different electrolytic conductivity (EC), i.e. 0.94 dS m-1 (low EC; LEC) and 6.72 dS m-1 (high EC; HEC), to investigate the effect of N availability and salt content on organic material decomposition. Inorganic N dynamics and production of CO2 and 14CO2 were monitored. Approximately 60 % […]