چكيده لاتين :
Introduction
Climate changes are the most important event in the Quaternary period and Playas are the climate
changes legacy. Playas are legacies of the Quaternary climate changes and have the special position
among of the geomorphological areas of Iran, especially in the dry areas. Terraces, alluvial fans
sequences and coastlines movement are main evidences base-level changes during the Quaternary.
Playas and lakes or generally inner craters have a key role in the climatic balance and ecological
changes in the Quaternary, in their surrounding areas and always have been considered to determine
past climates.
Lut desert in Iran's southeastern is in the area of Sistan And Baluchestan, and Kerman provinces.
Iran Yardang is formed in west of the central Lut Desert that is the unique example of the
magnitude and extent. This lake is located in the South Lut, south-eastern of Iran in the Yardangs
range.
Materials and Methods
In this study, we have examined the geomorphological (lake terraces) and sedimentological (lake
sediments) evidences to review the range of Lut lake. The documents and library materials
(including books, Persian and English articles and dissertations), video sources (including
geological maps, ETM satellite sensor Landsat imagery, TM and Digital Elevation Model SRTM 90
m and Dem 10 m), visiting and sampling of the area (Terraces and lake levels of area were visiting
and terraces were sampled to approve the lake sediments) as well as laboratory operations were
used. In this research, they have been observed terraces in the northeast areas of Yardang by field
studies and sediment sampling was conducted to confirm sedimentology date for the marginal area
of the past lake. Also, with the passage of air in the southeast region is detected terraces in the
location and similar terraces in the eastern regions are determined by using satellite imagery and
digital elevation model. Based on height data obtained from the terraces that they are the lake water
level in the Quaternary, it was rebuilt lake range for Lute, being specified the lake dewatering range
in prior periods determining the extent of the lake. Also, with tests on sediment samples and
eventually the calculation of the indices due to sedimentary indexes and examination of sediments
features with an average small to medium sandy sediments, sandy sediment conditions has been
approved in the lake margins in Quaternary.
Discussion and Results
Checking the Lut Desert terraces indicates that the terraces around these plains have not similar
height, but according to study, 330 350 404 m depth by using of a Digital Elevation Model and
compliance with satellite images having best match to the lake terraces of around the hole. Based on
these curves, the lake border is designated in different phases of advance and retreat in the area. wheat showed that it was grown in the basaltic foothills of the mountains of Karajadagh in
southeastern Turkey as a volunteer plants, and settlements used the grains and later to cultivate it
(WAN-friendly, 1981). The accurate studies were not done about the domestication of wheat
together as what time epigenetic changes occurred in Einkorn and Emmer wild type in Iran.
Research results showed that the dominant food of Zagros residents was cereals (especially wheat)
in 9000 years ago (Brvshky et al., 2016).
Man collected wild grains at least 20,000 years ago and knew that plants are grown better in a
certain conditions. They were produced less yield or dead due to pests and disease at some years’
time. Recent finding related to results of survey of wild genes of agricultural products revealed that
domestication of plant has been often took place in Asia more than 12,500 years ago (Salamís &
others, 2002). Einkorn and emmer wheat, barley, peas, lentils, buffalo pea and flax were
domesticated at the first time in the Fertile Crescent (Hillman, 1966). Einkorn wheat was the first
variety which successfully cultivated. It was a diploid species that was domesticated in the Fertile
Crescent more than 12,500 years ago. However, the cultivation the wheat was stopped in 5500 years
ago.
Conclusions
Wheat has been migrated to China from the Middle East, throughout the Silk Road and other
transportation routes. Southern parts of central China was old and drier than the Middle East. The
southern China districts had a warm humid climate in 7,000 years ago, but there was a relatively
cool and dry conditions in 6300 years ago and the size of grains of wheat and rice were smaller and
similar to its current state at the same time. The size of wheat seed was reduced in the 2000-5000
years ago. It could be said that climate changes during the Yangrdryas period has been effective on
domestication and increasing the power adaptation of wheat in different geographical areas.
However, before that, wheat was cultivated for a long time but, it did not have the properties of
domesticated wheat. Cold and dry climatic conditions in Yangrdryas (12,500 years ago) and dry
climate in 5000-6000 years ago causes increasing the resistance of wheat and, created more
morphological and mutagenesis changes. According to the report (IPCC, 2007) warming of the
Earth by 0.13°C per decade in the last 50 years is almost two times of the rate of recent past 100
years. Temperature increase has been estimated 0.74°C in the last century. Wheat is sensitive to
high temperature, but the sensitivity depends on several factors such as variety, ambient
temperature in which corn growth and its growth stages. The experiments showed that temperature
increase affected wheat growth, and this reduces the crop growth period and the crop yield and
quality will be decreased, consequently. Warmer climatic conditions is effective in reduction of
fertility, changes in size, crop seed shape and quality, and achievement of consistency with current
climatic conditions for cereals in low and middle latitudes. With the transferring of agricultural
belts to high latitudes, although, there will be a desirable temperature conditions to grow wheat,
factors including high humidity, poor soil organic matter, and low thickness of the soil are the most
important issues restricted the wheat cultivation. Moreover, the probability of the pests and fungus
outbreak will be increased for cereals.
