نتایج جستجو برای: arid rangelands

تعداد نتایج: 20677  

2015
Hasen M. Yusuf Anna C. Treydte Jauchim Sauerborn Raffaella Balestrini

High grazing intensity and wide-spread woody encroachment may strongly alter soil carbon (C) and nitrogen (N) pools. However, the direction and quantity of these changes have rarely been quantified in East African savanna ecosystem. As shifts in soil C and N pools might further potentially influence climate change mitigation, we quantified and compared soil organic carbon (SOC) and total soil n...

2001
K. Kellner

The biophysical environment is an important determinant of land degradation in both commercial and communal land tenure systems in South Africa. According to a recent study on the status of land degradation, approximately 25% of the total land cover in South Africa is degraded. Several technologies exist to restore the soil and vegetation degraded areas in natural pastures. To improve the produ...

1996
G. N. Flerchinger C. L. Hanson J. R. Wight

Transport of mass and energy between and within soils, canopies, and the atmosphere is an area of increasing interest in hydrology and meteorology. On arid and semiarid rangelands, evapotranspiration (ET) can account for over 90% of the precipitation, making accurate knowledge of the surface energy balance particularly critical. Recent advances in measurement and modeling have made the accurate...

2006
A. Ghorbani D. Bruce F. Tiver

Resource stratification for ground-based and remotely-sensed methods of rangeland assessment is essential for locating appropriate sampling sites. This is particularly the case when site comparisons are required, as in the case of grazing gradient analysis, wherein the objective is to limit the number of environmental variables. This study compared stratified units derived from supervised, unsu...

2007
P. A. Cipriotti P. Flombaum O. E. Sala M. R. Aguiar

Current climate change models for arid ecosystems challenge our ability to understand the effects of droughts on plant population dynamics. In a sandy soil plant community from the Patagonian steppe, we studied soil water dynamics and its effects on grass regeneration. Our hypothesis was that a decrease in precipitation would not change soil water dynamics of the top soil layer where most of th...

2013
Habtamu T. Keba I. C. Madakadze A. Angassa A. Hassen

We examined the nutritive value of common grass species in the semi-arid rangelands of Borana in southern Ethiopia using local experience based herbage preference (LEBHP) perception and laboratory techniques. Local pastoralists in the study area were asked to identify common grass species and rank them according to the species' preferences and palatability to cattle. The pastoralists listed a t...

2011
G.vanN. du Toit H. A. Snyman

________________________________________________________________________________ Abstract Grazing levels and rotational schemes need to be tailored to each individual farm or pasture, and more studies are needed on the resilience of rangelands and on separating the effects of grazing and climate. The direct short-term impact of three rates of stocking (4, 8 and 16 Small Stock Units-SSU/ha) was ...

2004
R. Douglas Ramsey Dennis L. Wright Chris McGinty

Many land-management agencies are caught between decreased budgets and increasing public interest. Furthermore, semi-arid landscapes are sensitive to management prescriptions and use, and require a significant amount of monitoring in order to assess vegetation productivity and health. The purpose of this study was to evaluate the use of Landsat Enhanced Thematic Mapper (ETM) Imagery to monitor ...

2016
Mahmud A. Muminov Jie Meng Caihong Li Liyue Guo Cheng Da Gaoming Jiang

This paper describes the capability of remote sensing in the monitoring of rangeland vegetation productivities and dynamics in the foothill areas of Uzbekistan, in order to enhance the sustainable utilization of natural resources. Seasonal productivity, including above-ground biomass, density, coverage, foliar chlorophyll, and carotene content, was measured for the Artemisia diffusa, the domina...

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