There is currently no consensus on the importance of climate change in Mesoamerican prehistory. Some invoke drought as a causal factor in major cultural transitions, including the abandonment of many sites at 900 CE, while others conclude that cultural factors were more important. This lack of agreement reflects the fact that the history of climate change in many regions of Mesoamerica is poorl...

Among abiotic stresses, drought is considered as the most important growth limiting factor, especially in arid and semiarid regions. Drought impacts can be adjusted by soil microorganisms. Accordingly, the present study was organized in order to the increase the tolerance of lemongrass (Cymbopogon citratus)to drought using plant growth promoting rhizobacteria (PGPR). Treatments were wa...

While much is known about the factors that control each component of the terrestrial nitrogen (N) cycle, it is less clear how these factors affect total N availability, the sum of organic and inorganic forms potentially available to microorganisms and plants. This is particularly true for N-poor ecosystems such as drylands, which are highly sensitive to climate change and desertification proces...

Arid regions are an important part of the world as they cover more than 40% of the land surface and they can provide sufficient opportunities for extensive development. However, urban development of these regions is facing a set of problems. This is besides the development barriers due to the arid regions climate associated with a set of economical, social, administrative, and physical problems...

Evapotranspiration (ET) is a key component of the water balance, especially in arid and semiarid regions. The current study takes advantage of spatially-distributed, near real-time information provided by satellite remote sensing to develop a regional scale ET product derived from remotely-sensed observations. ET is calculated by scaling PET estimated from Moderate Resolution Imaging Spectrorad...

two hundred and ninty four engorged female ticks were collected from 4 different geographical regions for assessment of tick resistance against acaricide compounds.the 15-21 day- old larvae have been tested in accordance with fao recommended larvae packet test .resistant factor for each region was calculated by lc50 and lc99. minimum lc50 (0.008)and, maximum lc50 (0.024) for amitraz were seen i...

Shallow-rooted grasses and deep-rooted shrubs dominate arid ecosystems where nitrogen is concentrated in the upper layers of the soil and water is distributed throughout. Analysis of mineral nitrogen and absorption patterns using a tracer indicated that shrubs in Patagonia absorbed nutrients from the lower, relatively nutrient-poor layers of the soil. Are they, consequently, at a competitive di...

Some land and ocean processes are related through connections (and synoptic-scale teleconnections) to the atmosphere. Synoptic-scale atmospheric (El Niño/Southern Oscillation [ENSO], Pacific Decadal Oscillation [PDO], and North Atlantic Oscillation [NAO]) decadal cycles are known to influence the global terrestrial carbon cycle. Potentially, smaller scale land-ocean connections influenced by co...

Soil degradation is one of the most serious ecological problems in the world. In arid and semi-arid northern China, soil degradation predominantly arises from wind erosion. Trends in soil degradation caused by wind erosion in northern China frequently change with human activities and climatic change. To decrease soil loss by wind erosion and enhance local ecosystems, the Chinese government has ...