نتایج جستجو برای: فیروزکوه؛ Agropyron intermedium؛ Oryzopsis holciformis Thymus fedtschenkoi
تعداد نتایج: 17521 فیلتر نتایج به سال:
یکی از فاکتور های مهم در تعیین ظرفیت چرایی، مشخص کردن میزان بهرهبرداری مجاز گونهها میباشد. این بررسی جهت تعیین بهترین شدت برداشت علوفه گونههای معرف وکلیدی,A.intermedium O.holciformi,s و T.fedtschenkoi در مراتع نیمهاستپی سرد فیروزکوه در طول سالهای85 تا 89 به اجرا در آمد. تیمارها شامل شدتهای مختلف برداشت 25، 50 ، 75 درصد و شاهد بودند. در سال اول محدودهای به مساحت یک هکتار انتخاب و حصارک...
در این تحقیق اثر شدتهای مختلف برداشت از علوفه سال جاری و همچنین اثر سال( با میزان بارندگی متفاوت) بر میزان تولید علوفه 3 گونه مرتعی Stipa arabica، Oryzopsis holciformisوPoa bulbosa در سایت نیمهاستپی کوه پنج در استان کرمان در4 سال متوالی از 1386تا 1389 به منظور تعیین حد بهره برداری مناسب این گونهها، بررسی شد زیرا با توجه به تحمل میزان گونه های مرتعی نسبت به چرا، می توان حد بره برداری مناسب ا...
background & aim: the genus thymus belonging to the family of lamiaceae and consist over 215 different species throughout the word. eighteen species grow naturally in iran of which four species are endemic. experimental: this reseach has been carried in medicinal plants research station in yazd province with the coordinates of longitude and latitude 55 31 49 northly, 27 15 54 east to heigh of 1...
Degradation of plant patches is considered as one of the indices for rangeland degrading health condition. Investigating the accuracy of triple indices (infiltration, stability and soil nutrient cycle) presented by LFA method seems necessary to determine its efficiency in semi-arid areas with the least cost. This study aims to investigate the role of vegetative species and growing forms on soil...
this study investigates the relationship between litter quality and aerial parts of plant on c, n, k, p and c/n ratio of soil in four rangeland species including agropyron intermedium, bromus tomentellus, eurotia ceratoides and kochia prostrata. after recognizing the sites of these species in hamand absard located in 65 km of northern tehran, at the end of growing season, samples of litter, aer...
Native grasses interact spatially with themselves and their environment and can therefore be thought of as a system of dependent random variables. One method of modeling the spatial dependence of a multi-species population is a Gibbsian pairwise potential model. Since natural selection operates at the level of individual plants, the information obtained from such a model should provide a greate...
The study of vegetation dynamics under grazed and non-grazed rangelands is one of the most important prerequisites for range improvement. In this research, vegetation composition and the vegetation functional groups were compared in an exclosure site (livestock excluded for six years) and grazed area in semi-steppe rangelands in Tehran province. Systematic random sampling technique through the...
Multicolour genomic in situ hybridization (mcGISH) using total genomic DNA probes from Thinopyrum bessarabicum (Săvulescu & Rayss, 1923) Á. Löve, 1984 (genome J(b) or E(b), 2n = 14), and Pseudoroegneria spicata (Pursh, 1814) Á. Löve, 1980 (genome St, 2n = 14) was used to characterize the mitotic metaphase chromosomes of a synthetic hybrid of Thinopyrum intermedium (Host, 1805) Barkworth & D.R. ...
The effects of environmental conditions on population trends of plant-parasitic nematodes were studied in experimental plots of five wheatgrasses in the western Utah desert. In a 3-year (1984-86) field study, soil water and temperature affected the population trends of the ectoparasites, Tylenchorhynchus acutoides and Xiphinema americanum, and the migratory endoparasite, Pratylenchus neglectus,...
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