dryland winter wheat (triticum sativum l.) generally grown in rotation with fallow or chickpea (cicer arietinum l.) constitutes a major crop in the west region of iran. information is limited on the success of more intensive dryland cropping systems while applying conservation tillage management. an experiment was conducted to determine the effect of five tillage systems on soil physical proper...

Germination from the soil seed bank (SSB) is an important determinant of species composition in tropical forest gaps, with seed persistence in the SSB allowing trees to recruit even decades after dispersal. The capacity to form a persistent SSB is often associated with physical dormancy, where seed coats are impermeable at the time of dispersal. Germination literature often speculates, without ...

Nowadays, new materials are widely used for improving the bearing capacity of the soils and geosynthetics include the type of these materials which are utilized in this regard. In addition, the geofoam panel type of geosyntethic materials is useful and an alternative for backfill in retaining wall or pavement layers. The present research mainly aimed to investigate sthe effects of geofoam parti...

The surface material at the Surveyor 5 site is granular and slightly cohesive. Spacecraft footpads plowed trenches in this material as the spacecraft slid during landing. For a compressible soil model, a static bearing capacity of 2.7 newtons/cm •' gave best agreement with the observations. Static firing of the vernier engines against the surface moved surface particles; a crater 20 cm in diame...

Many avocado growers are debating the question of whether or not to apply calcium to their groves. Some advocates say calcium is a necessary soil additive, creating almost magical improvements in soil chemical balance and tree growth. Others maintain that, since calcium is common in California soils, it serves only to improve soil structure in sodic soils or soils with permeability problems due...

infiltration plays an important role in surface and subsurface hydrology and it is a key factor in the rainfall and runoff equations. the use of new approaches that have no limitations of common theoretical and empirical methods to determine infiltration relationships, will minimize the necessity of time consuming and costly experiments to determine permeability values and will make it possible...

The effect of indoor gamma dose rate, permeability of soil, substructure, and ventilation habits of inhabitants were studied using data of 84 low rise residential houses collected in an area of enhanced indoor radon concentration. The radon concentrations varied from 30 to more than 5000 Bqm. Cross-tabulation, comparisons of means and multiplicative models were used to test the significance of ...

The relative potential for elevated residential indoor radon has been mapped for the City of Fort Collins, Colorado. Using published geologic maps and soil permeability information, the study area was divided into geologic and soil permeability (geoperm) units. Evaluation of the data showed a relationship between residential basement indoor radon concentrations and geopenn units. Mean indoor ra...