Climate and vegetation of Lut desert

The amount of rain in or near this basin is very low and limited to the cold season. According to the summary of atmospheric statistics In different stations, there is no rain in the hot season, and the average annual rainfall in the cold season in Kerman is 110. It is 40 mm in Bam, 78 mm in Zahedan, 45 mm in Zabul and 180 mm in Birjand. The annual average temperature in these areas is relatively high, and for this reason, the amount of evaporation in the hot season increases sharply, especially in the Lut Plain. The amount of annual rain in the heights near the plain is slightly more than the figures recorded above, but the amount is not significant. There are few snow-bearing peaks and their snow melts quickly at the end of the cold season or at most at the beginning of the warm season; Therefore, the only source of water for rivers and canals is, firstly, the rains of the cold season and then the springs that are scattered in the upper part or the middle of the canals. About 20 kilometers from Shahdad, trees and Gaz shrubs are located in desert pots of Lut, which are called Nebka or plant mounds. The lands between the nabkas are covered with sand, and the nabkas generally appear on a flat surface where the amount of sand is medium and the water level under the ground is high or the available moisture is sufficient for the life of the vegetation. Nebka constituent elements include sand-lay, clay and celt. The shape of the nebka is a function of the size, density and growth rate of the host plant, which are species such as a group of grasses, thorn shrubs, sedges, etc. Tamarix is one of the host species of Nebkas in Lut Plain. The height of Nebkas ranges from several decimeters to several meters and its length ranges from one meter to 10 meters. It is worth noting that individual plants must be more than 10-15 cm tall to control sand. If the sand grains do not have adhesion, in other words, they do not have clay elements, their volume changes with the change and wind speed. With the increase in the amount of sediment, the plant continues to grow in the upward direction to avoid being buried. This growth is until the root of the plant is in contact with the underground water level. It may eventually lead to Nebka s death. Many-year and permanent nebkas play an essential role in changing the level of underground water table, waste water, evaporation, transpiration and wind sediment control in the region. Rebdou are distinguished from Nebka by their larger size. Their length reaches 2 to 7 meters and their width reaches 1 to 5 meters. Apart from the dimensions, the shape of the Rabdus is also more complicated than the Nabkas; and sometimes it shows several cones that are placed together. The highest Rabdus can be seen in Western Lut, sometimes their height reaches 12 meters (the height of a 4-story building).