the study was performed for assess the environmental factors affecting weed species diversity and composition of wheat (triticum aestivum l.) fields in jajarm, north-khorasan of iran, in 2009. the crop management (herbicide, amount of nitrogen applied and preceding crop type) and edaphic factors (ph, texture and content of phosphorus) of 16 fields were collected. shannon’s diversity index, spec...

evaluation diversity of agricultural plants and effectiveness of management factors in non-hunting of gharaviz abstract biodiversity is the basis of agriculture. sustainable agriculture both promotes and is enhanced by biodiversity. during present study, agrobiodiversity and management factors were investigated in three villages of gharaviz area and four villages in surroundings area, in sarpol...

biodiversity refers to all forms of living animals, plants and microorganisms and agro-biodiversity is a component of biodiversity that represents diversity in arable lands. the aim of this study was to determine the biodiversity status of agro-ecosystems of shahr-e-rey city located in south of tehran, through calculating species richness index using rarefaction method. to the collect required ...

13 The Genealogical Sorting Index (gsi) has been widely used in species-delimitation studies, where 14 it is usually interpreted as a measure of the degree to which each of several predefined groups of 15 specimens display a pattern of divergent evolution in a phylogenetic tree. Here we show that the gsi 16 value obtained for a given group is highly dependent on the structure of the tree outsid...

The aim of this research was to investigate the effect of index species, Astragalusammodendron on the associated plants of Agropyron tauri and Bromus tomentellus fromdifferent aspects in Shazand rangeland in southwest of Markazi province. The effects ofspecies density and distribution pattern and then index species on the soil properties werestudied. Based on the randomized – systematic method,...