نتایج جستجو برای: total ratio vegetation index trvi

تعداد نتایج: 1555903  

2015
Rodrigo Marciente Paulo Estefano D. Bobrowiec William E. Magnusson Danilo Russo

Vegetation clutter is a limiting factor for bats that forage near ground level, and may determine the distribution of species and guilds. However, many studies that evaluated the effects of vegetation clutter on bats have used qualitative descriptions rather than direct measurements of vegetation density. Moreover, few studies have evaluated the effect of vegetation clutter on a regional scale....

2015
Yan Yan Xuyang Lu Harpinder Sandhu

Overgrazing is considered one of the key disturbance factors that results in alpine grassland degradation in Tibet. Grazing exclusion by fencing has been widely used as an approach to restore degraded grasslands in Tibet since 2004. Is the grazing exclusion management strategy effective for the vegetation restoration of degraded alpine grasslands? Three alpine grassland types were selected in T...

2002
M. S. Moran T. R. Clarke Y. Inoue A. Vidal

T e crop water stress index (CWSI), developed at the USDA-ARS [LS. Water Conservation Laboratory, Phoenix, Arizona, is a commonly used index for detection of plant stress based on the difference between foliage and air temperature. Application of CWSI at local and refzional scales has been hampered by the difficulty of measuring foliage temperature of partially vegetated fields. Most hand-held,...

Journal: :Remote Sensing 2010
Jerry L. Hatfield John H. Prueger

The paper investigates the value of using distinct vegetation indices to quantify and characterize agricultural crop characteristics at different growth stages. Research was conducted on four crops (corn, soybean, wheat, and canola) over eight years grown under different tillage practices and nitrogen management practices that varied rate and timing. Six different vegetation indices were found ...

2008
Paul M. O’Neill Remy Dehaan Jeffrey P. Walker Iain Hume

Obtaining measurements of the near-surface soil water content from passive microwave observations requires knowledge of the soil effective temperature, which is a function of the soil temperature and moisture profiles. Detailed information on these profiles is not available from airborne remote sensing, but the effective temperature can be estimated via thermal infrared observations of the land...

Journal: :Remote Sensing 2017
Jan G. P. W. Clevers Lammert Kooistra Marnix M. M. van den Brande

Leaf area index (LAI) and chlorophyll content, at leaf and canopy level, are important variables for agricultural applications because of their crucial role in photosynthesis and in plant functioning. The goal of this study was to test the hypothesis that LAI, leaf chlorophyll content (LCC), and canopy chlorophyll content (CCC) of a potato crop can be estimated by vegetation indices for the fir...

2010
FEI LI YUXIN MIAO XINPING CHEN HAILIN ZHANG LIANGLIANG JIA GEORG BARETH

Plant biomass and nitrogen status are important factors to consider when making in-season crop management decisions. Traditional sampling and analysis are time-consuming, labor-intensive and costly. It is desirable to estimate these parameters nondestructively using remote sensing technology. The objective of this study is to evaluate the potential of using an active crop canopy sensor, GreenSe...

Journal: :Remote Sensing 2014
Weicheng Wu

A large number of vegetation indices have been developed and widely applied in terrestrial ecosystem research in the recent decades. However, a certain limitation was observed while applying these indices in research in dry areas due to their low sensitivity to low vegetation cover. In this context, the objectives of this study are to develop a new vegetation index, namely, the Generalized Diff...

2013
Chengchen Pan Halin Zhao Xueyong Zhao Huibang Han Yan Wang Jin Li

Grassland salinization causes considerable changes to soil and vegetation, which can lead to changes in soil organic carbon (C) and total nitrogen (N). These changes have complex causal relationships. A significant correlation between soil organic C and total N and any soil or vegetation property does not necessarily imply a significant direct effect of the property on soil organic C and total ...

The present study aimed to assess the spatio-temporal changes in the natural vegetation cover of Ahl Iman watershed, Ardabil province. For this purpose, land use maps of the three years (2000, 2010, and 2020) were extracted from Landsat satellite images. Then, seven landscape metrics (patch density, edge density, patch richness, splitting index, contagion index, Euclidean nearest neighbor dista...

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