Agricultural soils can act as a source or sink of atmospheric C, according to the soil management. This long-term experiment (22 years) was evaluated during 30 days in autumn, to quantify the effect of tillage systems (conventional tillage-CT and no-till-NT) on the soil CO2-C flux in a Rhodic Hapludox in Rio Grande do Sul State, Southern Brazil. A closed-dynamic system (Flux Chamber 6400-09, Licor) and a static system (alkali absorption) were used to measure soil CO2-C flux immediately after soybean harvest. Soil […]

Surface lime application to an acid soil under no-till system and normal rainfall conditions increases yield and crop root growth near the soil surface, but the effects of lime sources like flue dust, sewage sludge and aqueous lime have not been fully investigated . The experiment aimed to evaluate the effects of surface application of different lime sources on soil chemical attributes of a clayey, dystrophic Oxisol and black oat root growth and yield under a no-till system. Evaluations were […]

This review aimed to compile information on the effect of plant-produced organic compounds on soil nutrient availability, especially on the cations Ca, Mg and K, and on the anion phosphate. The tillage system alters the soil chemical and physical properties, especially the nutrient availability and soil physical conditions. Due to the absence of soil plowing and deposition of crop residue on the soil surface, nutrient accumulation has been observed in soil surface layers in the no-till system. Plant organic acids […]

The organic carbon accumulation observed in soils under no-till system can increase the soil elasticity, resulting in a higher resistance to soil compaction. This study was carried out to evaluate the effects of water content and soil organic carbon (SOC) enrichment on soil elasticity. Samples of a Hapludalf and a Typic Hapludox in southern Brazil, both with a significant variation in SOC content, were equilibrated at four different water tensions, and then loaded and unloaded on a uniaxial apparatus. The […]

Through the densimetric fractionation it is possible to study the physical protection of soil organic matter (SOM). High density solutions of sodium iodide (NaI) or sodium polytungstate (SPT) have been indistinctively used for this purpose. This study aimed to assess: (a) the capacity of these two solutions at a density of 1.8 g cm-3 (NaI-1.8 and SPT-1.8) and of SPT at densities of 2.0 (SPT-2.0) and 2.2 g cm-3 (SPT-2.2) to increase C recovery in the free light fraction (FLF) and occluded light fraction […]

With the prevalence of no-till systems in Central-Western Brazil, a more in-depth knowledge about cover crops for straw production is necessary. The objective of this study was to evaluate the green and dry biomass production, the percentage of soil cover, as well as the dynamics of residues decomposition of three cover crop species, in the second growing season of the cropping year: amaranth (Amaranthus cruentus L. BRS Alegria), pearl millet (Pennisetum glaucum L. var. ADR500) and finger millet [Eleusine coracana […]

The timing of desiccation of the cover crop before crop sowing can favor the development of the plants and, consequently, increase yields. The purpose of this study was to evaluate the effects of intervals after desiccation of distinct cover crops and corn sowing on soil fertility, nutritional content and the initial development of corn. The experiment was carried out under controlled conditions in a greenhouse, and consisted of the following treatments: four desiccation periods preceding the corn crop (21, 14, […]

Microbial biomass carbon and organic carbon were measured in a long-term field experiment (20 years) in Planaltina, DF, Brazil, under corn-soybean crop rotation. Six management systems were selected: disk plow before planting (ADPP); disk plow after harvesting (ADPC), no-till after disk plowing in the first year (PDAD); moldboard plow before planting (AVPP); moldboard plow after harvesting (AVPC), no-till after moldboard plowing in the first year (PDAV) and an undisturbed area of Savanna type vegetation, Cerrado (CE) as a reference. Soil samples […]

Among conservation tillage methods, no-till has shown to be the most effective in reducing soil losses caused by rainfall erosion, but with considerable data variation regarding water loss. Considering these aspects, this study was carried out with the objective of evaluating soil and water losses, the chemical demand of oxygen (CDO), electrical conductivity, and the pH of surface runoff, associated with interrill erosion under simulated rainfall. The field study was conducted in October 2003 in Marechal Cândido Rondon county, western […]

The microbial biomass is a living component of the organic matter responsive to changes caused by different soil management systems. The objective of this long-term study was to determine microbial biomass carbon and nitrogen in response to different management systems in a clayey Red Latosol cultivated with corn in the Cerrado. The field experiment was conducted on an experimental area of Embrapa Cerrados, Planaltina, in the Federal District. Eight soil management systems with different implements and periods of crop residue […]