نتایج جستجو برای: vegetation cover percentage

تعداد نتایج: 280240  

Journal: :journal of rangeland science 2016
adel m. a. mahmoud mohd hasmadi i. alias m. s. mohamad azani a.

the degradation rate of mediterranean steppes, especially in north africa is 1% per year, and this considered as high a rate of degradation. this study conducted in 2014 in the south slope of the al-jabal al-akhdar, northeast libya to quantify the vegetation recovery rate and assess selected vegetation indices (vis) for mapping rangelands degradation status using remote sensing technology. thro...

Journal: :journal of agricultural science and technology 0
h. asadi department of soil science, faculty of agricultural engineering and technology, university of tehran, karaj, islamic republic of iran. m. honarmand department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. m. vazifedoust department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran. a. moussavi department of soil science, faculty of agricultural sciences, university of guilan, rasht, islamic republic of iran.

risk assessment of soil erosion, one of the most important land degradation problems worldwide, is very essential for land and water resources management, and development of soil conservation methods. in the present study, the temporal changes of soil erosion risk were assessed from 1987 to 2010, based on the revised universal soil loss equation (rusle) using remote sensing (rs) and geographic ...

2006
ANDREW J. ELMORE SARA J. MANNING JOHN F. MUSTARD JOSEPH M. CRAINE

1. Throughout arid regions of the world, groundwater is extracted for human population centres. In the Great Basin and Range region of the USA, we lack basic information regarding some plant communities detailing the extent to which vegetation is threatened by groundwater extraction. This is particularly true for alkali meadow vegetation, which is restricted to zones of shallow groundwater yet ...

2000
M. JACOBA SALINAS GABRIEL BLANCA ANA T. ROMERO

Riparian vegetation is vulnerable to human impact worldwide, and this is especially so in arid areas, yet there have been few quantitative studies and this is especially so in Spain. The state of the riparian vegetation along three major rivers and seasonal watercourses of southeastern Spain was evaluated during 1992–93, using the species composition and community structure in watercourses of d...

2011
S. H. Kaboli

The evaluation of vegetation covers using conventional methods is difficult over arid areas due to several reasons such as lack of the suitable roads to these regions. Moreover, this task is time-consuming. For these reasons, remote sensing has been considered as an economic alternative for conventional field work. In this study, the feasibility of using IRS images in vegetation cover evaluatio...

Journal: :international journal of environmental research 2013
m.h. mokhtari b. ahmad h. hoveidi i. busu

metric (mapping evapotranspiration at high resolution with internalized calibration) is known as an appropriate surface energy balance model for the estimation of the spatial distribution of evapotranspiration (et) in semi-arid regions. based on lysimeter measurements, metric has shown et estimates of 10% on a sub-field scale on a daily basis. there is a need to identify how the model is sensit...

2009
Robert M. Pringle Mindy Syfert Jonathan K. Webb Richard Shine

1. Establishing mediumto long-term trends in habitat availability for endangered species is important for determining the causes of historical population declines and for designing effective management plans. For some animal species, relative habitat availability can be estimated using time series of aerial photographs, but the limited information in old black-and-white images makes it challeng...

Journal: :journal of agricultural science and technology 2010
gh. habibi bibalani b. majnounian

slope instability due to landslides is particularly common in iran. it is possible to fight against these hazards thanks to the roots of trees, which provide an important contribu-tion towards the stability of hillslopes. however, our knowledge of the effectiveness of roots for slope stability needs improvement. therefore this study was carried out on the effect of tree roots on slope stability...

ژورنال: آبخیزداری ایران 2019
, , soufi, majid, yasrebi, banafshe,

Gully erosion is one of the important forms of soil degradation especially in semi-arid areas. Gullies are occupying 13 percent of Ilam Province area. This research focused on studying the, topographic threshold of gullies, dominant process of gully initiation and development as well, in agricultural and rangeland land uses. Ilam province with 2 million hac area is located in western Iran. Ilam...

1997
David N. Cole Neil G. Bayfield

In order to promote an increased ability to compare results from different studies, a standard protocol for controlled trampling experiments is suggested. The procedure will provide information on both damage to vegetation in response to short-duration trampling and subsequent recovery over a one-year period. Changes in vegetation cover, vegetation height, bare ground cover, and the cover of in...

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