نتایج جستجو برای: dryland rainfed
تعداد نتایج: 4919 فیلتر نتایج به سال:
There have been many studies of the diverse impacts of invasions by alien plants but few have assessed impacts on water resources. We reviewed the information on the impacts of invasions on surface runoff and groundwater resources at stand to catchment scales and covering a full annual cycle. Most of the research is South African so the emphasis is on South Africa's major invaders with data fro...
this study was performed to investigate the photosynthetic partitioning pattern of materials to aerial parts of bread wheat in dryland conditions. it was as well to study its relationship with bread wheat resistance and grain yield in drought conditions. seven genotypes including two cultivars (azar2, sardari) and five lines were investigated in a field experiment through a randomized complete ...
Relative (actual / potential) evapotranspiration (RET) was derived using ten-day composite NOAA PAL datasets (8km x 8km spatial resolution) over Indian landmass and an operational energy balance algorithm for five agricultural years (June-May) between 1996 to 2001. This was used to characterize ‘Kharif’ (June-October) rice growing environment and its yield prediction in rainfed conditions. Inve...
Climate variability adversely impacts crop production and imposes a major constraint on farming planning, mostly under rainfed conditions, across the world. Considering the recent advances in climate science, many studies are trying to provide a reliable basis for climate, and subsequently agricultural production, forecasts. The El Niño-Southern Oscillation phenomenon (ENSO) is one of the princ...
This study assesses the vulnerability of Bulgarian agriculture to drought using the WINISAREG model and seasonal standard precipitation index SPI(2) for the period 1951-2004. This model was previously validated for maize on soils of different water holding capacity (TAW) in various locations. Simulations are performed for Plovdiv, Stara Zagora and Sofia. Results relative to Plovdiv show that in...
Improper use of natural resources, especially soil, causes its degradation and severe soil erosion. Water erosion is an important factor causing soil degradation. Land use change of pasture would result in severe soil erosion mainly due to the reduction of vegetation cover and also surface soil disturbance. The objectives of this study were to estimate the amount of sediment, runoff and nutrien...
Extended Abstract Introduction and Objective: Drought stress is one of the most important factors in reducing yield and barley production in rainfed arid regions, and counteracting or reducing the effect of stresses as a useful solution to increase barley yield. Therefore, improvement of stress-tolerant and suitable barley cultivars for arid and semi-arid regions is essential. Material and Me...
Drought is a major constraint affecting rice production, especially in rainfed areas across Asia, Africa and South America. Development of drought resistant varieties will considerably improve rainfed rice production. Rice breeding programs focusing on drought resistance by direct selection for yield under stress have made little progress to date. Incorporation of secondary traits contributing ...
Perchlorate (Cl4-) reservoirs that accumulated in semiarid unsaturated zones, similar to chloride (Cl-), can contaminate underlying aquifers if they are mobilized. The purpose of this study was to evaluate Cl)4- mobilization related to land-use change from natural to agricultural ecosystems in the southern High Plains (SHP, USA), where large ClO4- concentrations (< or =60 microg/L) are found in...
Biophysical crop simulation models are normally forced with precipitation data recorded with either gauges or ground-based radar. However, ground-based recording networks are not available at spatial and temporal scales needed to drive the models at many critical places on earth. An alternative would be to employ satellite-based observations of either precipitation or soil moisture. Satellite o...
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