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Akhmadov Khukmatullo Mahmudovich 1 , Kasirov Kokul Khasanovich 2 1 Tajik Forest Research and Development Institute, Dushanbe, Tajikistan 734055 2 Tajik Association for Woods and Wild Animals Protection, Dushanbe, Tajikistan 734025 ABSTRACT For the Pamirs Alai mountain system the highly geomorphologic-climatic zone is typical. Depending on complex of natural human conditions all the territory of the Pamir Alai divided is to the four zones- valley, low mountain, middle mountain and high mountain, where the process of the soil degradation has the different development. In the valley zone the soil degradation is presented by all varieties of dynamic processes. Depending on how long the lands have been irrigated they can be divided into five categories: irrigated lands, newly irrigated and perspective irrigated lands. In the resulted of the breaking techniques and norms of watering on the irrigated lands the soil erosion, landslide, gully erosion, irrigated erosion etc. Take place intensive development. The density of gullies on the newly irrigated lands comes to 46 unites per square kilometer and the index of the length of gullies - to 7.6 km. per square kilometer. The maximum intensity of the development of the gully erosion - to 654 m per year. Easily eroded mountain rocks, immense human load, the week shocks of earthquakes and other factors are the reasons of the intensive development of erosion. This lead to the formation of gigantic gullies and powerful landslide. In the valley zone the surface natural erosion is very weakly developed. The wide erosion is widely spread in the south and north of Tajikistan. The natural soil degradation is more intensively going on the low mountain zone than in the valley zone and the index of the human erosion decrease . The density of natural gullies and its total length increase. The washout of soil and rainout of the arable lands and winter pastures comes to 17 thousands ton per ha . The highest index of the soil washout can be watched in the Pistacia zone and is areas of different species of vegetation and it comes to 4.0 -13.0 tons per ha. The intensive developmen t of the degradation depends on the complex of natural factors and on the peculiarity of the growth of Pistacia. Besides the intensive development of the erosion is connected with the discrepancy of the index of the precipitation and dynamics of the leaf surface. The maximum index of natural soil washout and rain off is observing in the middle mountain zone. The intensity of the development of the human erosion decrease. This is connected with the peculiarity of the nature factors and the decreasing of the area of cultivated lands. The soil degradation in the nut forests with the plenitude 0,6 is almost absent (0,003-0,005 tons per ha) but then the plenitude is 0,1-0,3 its index comes to 0,7-4,0 tons per ha. However, the soil washout in the juniper forests comes to 0,6-100,0tons per ha. The smallest index of the erosion is observed under the grassy vegetation. The influence of the human factors in the high mountain zone decreasing and of the nature factors is increasing. The soil degradation is displayed differently in the different parts of the high mountain zone. Here the soil washout comes to 0,6-5,0 tons per ha. The wind erosion is widely spread around the Pamirs lakes. After the breaking-up of the USSR and the civil war in the Tajikistan new factors of the soil degradation development appeared. It were not typical for the investigated areas. The lack of fuel becomes the reason of cutting of valuable mountain forests. It increases the development of erosion processes and expands the areas of "futile" lands. There are Haloxylon forests in the south part of the Republic which protect soil from wind erosion. However, because of lack of fuel they are cut down. Barkhans and dunes are moving to the agriculture areas. Now these lands have turned to the sandy areas. The population growth in the valley zones of the Republic compelled the people to cultivate the former abandoned lands in the mountains and to cut the unique mountainous forests for agricultural needs. The incorrect cultivation of these lands causes the intensive development of erosion and landslide, gully erosion particularly and the formation of "moon" landscape. The problem of insufficient food after the civil war in the mountainous areas of Tajikistan became very important. It forced the population to cultivate very steep slopes (till 35 degrees) under cereal cultures which resulted in the intensive development of erosion and destroyed the fertile horizon of the soil during the short period of time (2-3 years). It leads to change of the landscape. On these slope the line erosion and the landslides are intensively developing. The washout of soil comes to 17 thou sand tons per ha. In the result of intensive grazing in all zones the "sheep paths" are formed. The straight line of the slopes turned is turned into the micro stepped slopes and the biodivercity is fully changes. The maximum quantity of "sheep paths" comes to 14 thousand units per km square. All of aforementioned factors that strengthen the development of the desertification in the mountainous territory gives us the foundation to define the new type of desertification, that is the high mountainous desertification. On the base of space photos the series of maps were made : map of the erosion; the degree of land degradation; of the density, areas, length and intensity of the development of the gully erosion; of the soil washout; of the potentially eroded lands. For the first time for the mountainous territory of the Central Asia we established the connection between the mountain rocks, slope steepness , slope gully and the appearance of the vegetation on their surface All mountainous territory were divided into seven categories by the degree of the index of negative relief forms and into 12 categories by the degree of the degradation. On the fundamental rocks under the influence of dynamic processes special forms, called "obburida" [ob- water (tajik) , burida - to cat (tajik)] are forming. For the highly geomorphologic zones the different methods of protection from degradation are offered. INTRODUCTION The Pamirs-Alai mountain system covers the whole territory of Tajiksitan, south and western parts of Uzbekistan, and south of Kyrgizstan. Depending on height-nature climatic conditions the whole mountain system divides into 4 zones. The soil degradation, salting and other dynamic processes flow differently. For each zone characteristic types of desertification are distinguished. The development of soil erosion, salting, raise of the underground water level, landslides depend on the complex of nature anthropological factors. However for each zone it is possible to define prevaling factors, which cause the intensive development of dynamic processes. The changes of modern land surface take place under the influence of the soil degradation (desertification) , such as water, wind, gully, surface and another kinds of erosion, internal erosion, landslide , karst etc. The soil degradation is wide-spread in the mountain ecosystems and annually this area increases . 97,9 % of territory of the Pamirs Alai (in the area of Tajikistan) is subjected to soil degradation. In 1973 this index came to 68%. During 60-80 the years many soil degradation problems were investigated. However, a lot of questions of the dynamic processes ( particularly desertification and these influence on sustainable development ) for the mountainous territory still remain unstudied and require the detailed exploration using modern methods and applications of space photos. These questions are of principle meaning in the process of projecting anti-erosion measures and solution of the social-economic processes. MATERIAL AND METHODS The research conducted over the whole territory of the Pamirs-Alai in field, experimental, expeditionary and laboratory conditions. The expeditionary methods ( methods by S.S. Sobolev, 1949) allowed to measure the soil washout by investigation of volume of rill erosion on the elements of the relief forms. The rain off and soil washout have been studied in the permanent plots rain off, length 5-30m., width 3-5m., slope steeples 5-28 degrees and on different slope exposition. The dynamic of development of gully erosion had been studied by the stationary method during 25 years on 250 gullies in all geomorphologic zones. The spreading of the soil degradation(surface ,rill, gully , irrigation and another varieties of erosion) have been studied in the base of space photos, our worked up methods for the mountain territory. The biodivercity have been investigated on the strongly eroded rangelands in different usage period by the metric method. (Ahmadov 1987) RESULTS Depending on complex factor in the different highly - natural belts the land desertification goes differently. In the valley zone the soil degradation is presented by all varieties of dynamic processes. The main reason of the intensive development is human factor. Depending on how long the lands have been irrigated, all irrigated lands can be divided into 5 categories, where in the result of their incorrect use the gully erosion irrigate erosion, interlay erosion, surface erosion, landslides etc. intensively develop. The density of gullies in the valley zone comes to 16 units per square kilometer and the index of the length of gullies 7.6 km per square kilometer. The maximum intensity of the development of the gully erosion 654 m per year. Besides the above mentioned factors the exit of the under ground water, easily eroded mountain rocks and the shocks of earthquakes promote of the further intensive development of the soil degradation. The surface natural erosion is very weakly developed here. The wind erosion is widely spread in the south and north of Tajikistan, where the dunes and barkhans are frequent to appear. The annual speed of their movement is up to 50 meters. The natural soil degradation is more intensively going in the low mountain zone than in the valley zone and the index of the human erosion decreases. The density of natural gullies and their total length increases. The washout of soil and rain off of the arable lands and winter pastures comes to 17 thousand ton per ha. The highest index of the soil wish out can be watched in the Pistachio zone and in the areas of different species of vegetation and it comes to 4.0 - 13.0 tons per ha. The intensive development of the soil degradation depends on the complex of natural factors and on the peculiarity of the growth of Pistachio. Besides, the intensive development of the erosion is connected with the peculiarities of the index of the precipitation's and dynamic of the leaf surface. The maximum index of natural soil wash out and rain off observed in the middle mountain zone. The intensity of the development of the human erosion decreases. This is connected with the peculiarity of the nature factors and the decrease of the areas of cultivated lands. The soil degradation in forests with the plenitude 0.6 is almost absent (0.003 - 0.005 tons ha), but when the plenitude is 0.1 - 0.3 its index comes to 0.7 - 4.0 tons per ha. However, the soil washout in the Juniper forest comes to 0.6 - 1,0 tons per ha. The smallest index of the erosion is observed under grassy vegetation (tabl.1). However in spite of this the soil wash out process several hundreds times larger than soil formation process. The influence of the human factors in the high mountain zone is decreasing and of the nature factors is increasing. The main cause of the desertification development in high mountainous zone is the climatic factor. Low precipitation (50-300 mm as snow), strong winds, the temperature regime and other parameters promote the intensive desertification development. The relief and geological structure itself also assist the soil degradation process. The majority of soil cover in the high mountainous zone belong to the unstable to the wind erosion kind of soils. Even the insignificant index of vegetation cover causes the desertification to decrease. However, during the last period there's an intensive cut down of Teresken bush has taken place, the plant which is the only soil protector from the wind erosion. This process causes the dry up of lakes, spring disappearance, development of sandy massifs (barkhans and dunes) that concur new territories. Very often the sand storms and hurricanes can be observed, which raise up in the air sand and salt from the dry salty lakes. All sandy massifs situated around the lakes and along the river valleys at the heights of 3,500-4,000 meters above the sea level. The intensity of barkhans and dunes spread goes up to the 10 meters per year. The rate of sand particles blow out in this area makes 7-20 mm per year.  The soil degradation is displayed differently in the different parts of the high mountain zone. Proceeding from the development factors the following types of erosion have been distinguished for Eastern Pamirs: water, wind, surface, nival; and for Western Pamirs and Central Tajikistan - surface, linear, pasture erosion. In the most part of the high mountainous zone, made up of low-washout rocks the erosion-denudation forms of relief are spread. We named them obburida [ob(tajik) - water, burida (tajik)-cut]. Depending on the complex of nature factors in different parts of high mountainous zone the soil washout comes to 10 - 1200 tons/ ha. The high mountain regions are used as summer pastures, thus causing the intensive development of pasture erosion. When working out the desertification maps for high mountain zones, the space photos have been used, which allowed us to improve the desertification mapping methods. One of main factors of the desertification in the natural belts is intensive grazing (tabl.2) In the result of the intensive grazing in all zones "sheep paths" are formed. The straight line slopes are turned into the microstepped slopes and the biodiversity fully changes. The maximum quantity of "sheep paths" comes to 14 thousand units per square km (tabl.3). The intensity of development of natural gullies various in wide scale. The maximum increase of gullies comes to 82.5 m, minimum-0.2m, and annual-3.4 m. The cosmic information is very valuable cartographical materials for study a lot of dynamic processes including soil degradation or desertification. Analysis and comparison of the space photos (SPh) with traditional soil - erosion materials show that in the SPh the water erosion, wind erosion, gullies erosion, irrigation erosion and other dynamic processes with greater exactness and authenticity discern. Dependence on colors, phototones, structure, texture ect. among of soil degradation processes in SPh could be distinguish different degrees of erodeness lands. On the basis of above mentioned signs were compile the map of the soil degradation.   DISCUSSION Definition of the different types of the desertification is discussion. More than 150 shapes of the soil degradation distinguish oneself in the former soviet literature. However, for the last time, in connection with adoption of the International nature protection Conventions the soil degradation identified with the desertification . Therefore it is necessary definition of the dynamic processes by scheme:  The soil degradation (desertification ) divides into the under (a) ground water, (b) salination, (c) swampy, (d) soil degradation (138 types) and (e) other dynamic processes. However, peculiarity of the nature condition of the mountain lead to formation of the specific types of soil degradation - (1) negative erosion denudation form of the relief (obburida) and (2) high mountain wind erosion. Besides numerous specific form of the degradation distinguish oneself for each high nature zone. REFERENCES Ahmadov, H.M. (1980) Razvitie erozii v gornikh territoriyah Yuga Sredney Azii. Dushanbe : 48 p. Sobolev, S.S. (1949) Razvitiye erozionnih processov v Evropeyskoy chasti SSSR. Moscow-Leningrad. Vol. 1: 305 p. |