to study the effects of scale and tillage management on variability of soil properties in adjacent lands of different tillage type, soil sampling was performed linearly along contour line from the middle position of slope with 5 m intervals. in overall, 45 soil samples were collected from a field with conventional up-down tillage and 40 samples from an adjacent filed with contour tillage. soil ...

the arya and paris model is a commonly accepted method to translate a particle-size distribution curve into a corresponding soil moisture characteristic curve using scaling parameter (α). the scaling parameter, in the original model of arya and paris (1981), was assumed constant (α=1.38) for all soil texture classes. in recent years, several studies have shown that α is not constant and its qua...

in temperate forests canopy gaps play an important role in driving stand dynamics. the purpose of this research was to compare soil characteristics in forest gaps with several size and its relation to beech regeneration density in lalis forest, chalous. in order to investigate factors, three gap sizes as small gap (200 m2), medium gap (400 m2), and large gap (600 m2) with three replicate were s...

Researchers have defined and mapped ecological regions of the United States based on similar patterns of ecosystems such as deserts, forests, and croplands. These studies are useful in regional research, monitoring, and environmental management because data can be more readily extrapolated within the same ecoregion and to regions with similar characteristics. The description of ecoregions is la...

The microbial ecology of the nitrogen cycle in agricultural soils is an issue of major interest. We hypothesized a major effect by farm management systems (mineral versus organic fertilizers) and a minor influence of soil texture and plant variety on the composition and abundance of microbial nitrifiers. We explored changes in composition (16S rRNA gene) of ammonia-oxidizing archaea (AOA), bact...

Salinization is the main characteristic of soils in arid and semi-arid regions which reduce the agricultural potential ofirrigated lands. Therefore, soil reclamation as well as determination of the leaching requirement for salt control is veryimportant for better plant growth. In this study, the effects of leaching on saline soils of Sistan region, southeast of Iranwere examined using unsaturat...