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...

Roots of Vetiveria zizanioides Nash (Mae Hae; Thai ecotype) planted in three different cultivation systems (normal soil, normal soil with added microbes and semi- hydroponically) were extracted using a simultaneous steam distillation and solvent extraction (SDE) apparatus. Yields of the essential oils obtained were 0.27, 0.18 and 0.06%, respectively. The separation profiles obtained by comprehe...

Random field modelling of soil variability allows significant statistical results to be inferred from field data; moreover, it provides a consistent framework for incorporating such variability in reliability-based design. Cone penetration testing (CPT) is increasingly appreciated because of its near-continuity and repeatability. Stressnormalised CPT parameters are included in widely used engin...

Anaerobic ammonium oxidation (anammox) is a globally important nitrogen-cycling process mediated by specialized microbes, and has been demonstrated to be ubiquitous in anoxic natural settings and bioreactors. However, our knowledge of its prevalence in different paddy soil types and along the depth profiles remains largely undocumented. Here, mesocosm incubations were constructed to investigate...

Both anthropogenic nitrogen deposition and exotic annual grass invasion are occurring in the coastal sage scrub vegetation (CSS) of southern California. A study was carried out to determine the effects of these changes on soil microbial communities. Soils were sampled under exotic grasses and the native shrub Artemisia californica along an urban-to-rural N deposition gradient, and in N-fertiliz...

Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupl...

Soil microbial biomass plays an important role in nutrient transformation in terrestrial ecosystems. Microbial biomass is also an early indicator of changes in total soil organic carbon. Thus, the main objective of this study was to identify and quantify the present status of soil microbial biomass carbon and nitrogen with various management practices in Himalayan rangeland. To meet the aforeme...

micromorphology is the branch of soil science that is concerned with the description, interpretation and, to an increasing extent, the measurement of components, features and fabrics in soils at microscopic level. the advantage of micromorphology is that, in micromorphological studies the soils are studied in their natural and undisturbed form and so, one can follow the processes that take plac...

A large reservoir of soil nitrate in desert subsoil zones has been demonstrated in previous studies; however, information on the subsoil nitrate reservoir and its distribution characteristics in the deserts of China is still limited. This study investigated the distribution patterns of soil total nitrogen (N), nitrate, ammonium, and stable isotopic ratios of (15)N (δ(15)N) in shallow (1 m) and ...