The microbial community structure in various microaggregates in a loamy sand soil was investigated. The microaggregates were separated into outer and inner aggregates using a series of soil washes. Further physical fractionation of inner aggregates was achieved by separation into coarse and fine sand as macroaggregate fractions, coarse and fine silt as microaggregate fractions, and clay. Resear...

It is expected that the agricultural intensification occurred in recent decades in the Argentine Rolling Pampa significantly alters the SOM reserves. Therefore, it is necessary to identify soil organic carbon (C) and nitrogen (N) fractions to understand the functionality and stabilization of these reserves. Our objectives were to study the NT effect in two crop rotations, corn-double cropped wh...

Two different approaches have been used to study relationships between soil and human health: aggregateand individual-level. Aggregate-level is the primary approach used in the geosciences and broadly relates spatial soil characteristics to geographic incidence of disease. However, this may not be appropriate for a wide range of exposures and disease outcomes. For example, many diseases with lo...

Recently, numerous studies of aggregate response to freezing have been reported. Aggregate stability has usually been inversely proportional to soil water content at the time of freezing (Bullock et al., 1988; Benoit, 1973; Bryan, 1971; Logsdail and Webber, 1959). Aggregates from poorly aggregated soils, however, are more stable when frozen at intermediate water contents (Mostaghimi et al., 198...

As part of the National Human Exposure Assessment Survey (NHEXAS) in Maryland, we collected indoor air, carpet dust, exterior soil, and duplicate diet samples from a stratified random sample of 80 individuals to evaluate aggregate daily exposure, contributions of specific pathways of exposure, and temporal variation in exposure to chlorpyrifos. We collected samples from each participant in up t...

Soil macroaggregates (>250 mm) are easily disrupted when wetted quickly, whereas microaggregates (50–250 mm) are highly stable. There is little knowledge of functional groups of bacteria from microaggregates that can stabilize soil and their diversity. We isolated the predominant bacteria from microaggregates collected from two agroecosystems: a site cropped to barley (40 years with tillage) an...