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Kasirov Kokul Khasanovich 1 , Akhmadov Khukmatullo Mahmudovich 2 1 Tajik Association for Woods and Wild Animals Protection, Dushanbe, Tajikistan 734025 2 Tajik Forest Research and Development Institute, Dushanbe, Tajikistan 734055 ABSTRACT The problem of the soil degradation (desertification) in the mountainous regions of the Central Asia with arid climate is very important. The ecosystem of the landscape mountains is very fragile and its inconsiderable infringement leads to the destruction of natural environment, having catastrophic consequences.The intensive development of the soil degradation in different highly geomorphologic- climatic zones depends on the complex natural- human factors. In the valley zone the soil degradation is presented by all varieties of dynamic processes (the gully erosion, irrigation erosion, interlay erosion, surface erosion, landslide etc.) The main reason of the intensive development is human factor. The natural desertification is more intensively going in the low mountain zone than in the vally zone and the index of the human erosion decreases. The maximum index of natural soil washout and rainoff observed in the middle mountain zone.The influence of the human factors in the high mountain zone is decreasing and of the nature factors is increasing. The soil degradation is displayed differently in the different parts of the high mountain zone. One of main factors of the soil degradation in the natural belts is intensive grazing, mass-cultivation of the very steep slopes and the deforestation. All mountain areas of the South Central Asia may be divided into 24 eroded regions and for each of them the complex antierosion methods is offered which will promote further decrease of the soil degradation. INTRODUCTION For each natural zone prevailing causes of soil degradation development are different. The impact of factors of dynamic processes development increases and decrease from one zone to another. The impact of anthropological, geological, factors on erosion processes decrease from valley zone to high-mountain zone. The relief of locality is reversibly increases. The maximum index of climatic, soil, vegetation factors of desertification development is observed in middle-mountain zone; high-mountain and valley zones the impact of these factors decreasing quickly. That's why coming from complex of natural factors we distinguish zones of natural and anthropological soil erosion. The problem of different factors' interaction and their impact on soil degradation for the conditions of mountain relief are very actual. The destruction or ignoring of one environment stability factor may cause catastrophic consequences and development of the series of dynamic processes. Thus, it is possible to recommend real anti-erosion measures basing on analyze of complex of desertification development factors. MATERIALS AND METHODS The impact of anthropological and natural factors has been studied by natural (the estimation of erosion by the size of rill erosion volume and on the rainoff plots; the estimation of long standing erosion intensity; the estimation of erosion by the degree of accumulation pond; the estimation of erosion by the module of flowing deposit), laboratory and analytical-statistical methods. RESULTS The erosion processes development depends on complex of natural and anthropologic factors. Among numerous causes of soil erosion, in each case there are prevailing causes distinguished, although it's a result of geomorphologic, geologic, climatic, soil-vegetation and economic conditions' impact. The nature of their combination determines the danger and intensity of one or other type of soil erosion. The most expedient classification of erosion factors would be: a) promoting factor - negative human economic activity; b) energetic factors - climate and relief; c) the interfering factor - vegetation; also partially the soil properties; d) changing - soil and land surface; The geomorphologic factor (relief of district) is one of the most significant. It has an impact on the nature of drain formation, speed and kinetic energy of the drain, i.e. affects by means of flowing down water. The erosion development degree in this process depends on the steepness, length, slope exposition their form, the deepness of local erosion basises, the area of water-collection, negative relief forms, at the bottom of which ravines usually develop etc. In the conditions of Tajikistan, the slope exposition affects greatly on surface drain and soil erosion, especially during the period of spring thawing of snow. The south-exposed slopes usually (except the high-mountains) more eroded and have more washouts, ravines (Table 1-2).   The investigation showed that the increase of the mountain slope 2, 3 and 4 times caused the soil washout to increase accordingly to 21%, 49%, and 69%. The investigations also showed that on the slopes with steepness 5-70 the soil washout was 27 t/ha; 150 - 176, 280 - 372 t/ha, i.e. with doubling of slope steepness the soil washout increases 6,5 times, and with four-multiplying - 14 times. The water-collection areas of negative relief forms promotes the gully development. On the south exposed slopes gullies develop with water-collection area of negative relief forms over 1 ha, and rarely gullies developed with smaller area. Convenient places for gully development are hollows, dips and dip-like downturns, which mouths are of above local bases of erosion - these are "hanging" negative relief forms. The appearance and development of erosion depend on mountain rocks, or their anti-erosion stability. For example, on sands with good water permeability the gully erosion is low developed. Only in irrigated lands some small anthropologic gullies are observed. Here, the wind erosion is widely spread. Compared to the sands and sandy soils, the loams easily destroyed by the of thawed and rain water flows. In the river terraces combined by alluvial deposits, plane and linear erosion is developed. The soils formed on deluvial and proluvial deposits, also are subject to the different intensity erosion. Thus, the majority of erosion forms are observed in loams, less - in alluvial, proluvial, and deluvial deposits and even less - in poorly - washed away dense basement rocks. The modern geologic processes - landslides, suffosion, solifluction, abrazia, karst and pseudo-karst, and also endogene processes play significant role in the development of soil erosion. The erosion process development is much predetermined by the climatic conditions with precipitation having significant role here. Besides the average annual and daily amount of precipitation, its intensity has a great impact on the soil erosion development. The raise of the intensity increases the kinetic force of raindrops, destroying the soil structure and decreasing its water-permeability. As a result, the water collected on the surface flows down and washes away the upper soil layer, leaving the jet washouts and rills. The winds also have a significant influence on the development of erosion processes. They blow off from the adjacent fields into the gullies not only the snow cover, but also the soil itself. The collected snow in gullies melts as the weather gets warm, slowly washing away the gully slopes. Unlike other factors causing the erosion process development, the vegetation cover plays main soil-protecting role; the drain and soil washout on the slopes with rich projective covering are much lesser, than on the slopes with rare vegetation. The development and intensity of erosion processes depend on the anti-erosion stability of soils and the fact, that soil cover of Tajikistan is very diverse. Depending on anti-erosion stability the soils of Tajikistan could be classified this way: gray-lands, mountain brown, high-mountain steppe and meadow-steppe lands. In section of geomorphologic zones, by the degree of susceptibility to the erosion, the soils could be placed in the following order: middle-mountain soils, hilly-foothills and low-mountain soils, high-mountain soils and valleys. The natural factors may create the conditions for natural soil erosion, but not causing its development. The main factor, promoting the intensive erosion process development, is wrong economic activity. As a result of intensive development slope grounds the erosion has spread widely. The main reason of this is overusing of lands without implementation of anti-erosion measures (ignoring of norms and techniques of irrigation, intensive overgrazing, improper road placement, imperfection of crop land development technologies etc.) All mountain areas of the South Central Asia may be divided into 24 eroded regions and for each of them the complex antierosion methods is offered which will promote further decrease of the soil degradation and can stabilize further sustainable development. The effectiveness of the AEM depends on combination of the nature factors. There is a complex of AEM for each high -natural zone (fig .1). However implementation the AEM do not always give the expected results. For more effective introduction of the AEM, it is necessary accomplish the complex of measures on softening and preventing of erosion processes (tabl.3). The basis here is sustainable development of country and financial support placed at the base of triangle. Depending on significance basic measures are placed in different parts of the triangle. Besides "the base" other main factors softening and preventing the desertification are three components placed in three sides of the triangle. Only observance of all these AEM will promote the softening and preventing of desertification. Combat to Desertification in the valley zone must be carried out in two directions: first -raise of soil resistance to wash out ; second - correct using of the irrigated lands and application of progressive soil protective irrigation techniques. The main effective the AEM must be : cessation of cultivation of one -year cultures on the steep slopes (more than 12 degrees) ; the use of eroded lands under perennial grass and gardens; deep cultivation across the slope ; introduction of modern surface methods irrigation; minimizing the excessive water and other. The gullies lands must be fill-up. It is proposed to plant the 2-10 rows shelter belts of dry-steady trees in the wind erosion zone. Arrangement of trees and quantity of rows depended on of directed and speed of the wind. For protection of the soil degradation in the low mountain zone (500(900)-1500 m ab. L.s.) necessary to take the system agro-meliorative measures and forest - meliorative measures. This zone use as rainfed for a long time , therefore all AEM must be directed to the further stopping and relation of the erosion processes. Here necessary to take the complex of the AEM - prophylactic measures, agro - meliorative measures, hydro - technical measures ect. The middle mountain zone (1500-2500 m above s.l.) using as summer pasture. The areas of the rainfed lands are insignificant. Therefore the main AEM is pasture - meliorative measures and agro-meliorative measures. Here specially must be sparely attention afforestation of the steep slopes. In previous years buffer zones and ,,handing ,, gardens have been widely used in the low mountain and middle mountain zones of Tajikistan. Now such application is very rare. The high- mountain zone (more than 2500 m above s.l.) in the main using as the summer pasture and therefore pasture meliorative measures play the important role. Application of the insignificant standards of mineral fertilizer and regulation of grazing are very effective specially. Other AEM are small effective. The high- mountain zone (more than 2500 m above s.l.) in the main using as the summer pasture and therefore pasture meliorative measures play the important role. Application of the insignificant standards of mineral fertilizer and regulation of grazing are very effective specially. Other AEM are small effective. 
DISCUSSION The implementation of AEM in mountain conditions is an important problem. The mechanic transportation of AEM from European part of the former USSR into the mountain territory often caused intensive soil erosion development. For the mountain territory it is necessary to recommend complex of measures as simple transportation of AEM from one zone to another is low effective. The best effect for the mountain territory render local, often ignored AEMs such as, buffer zones, "hanging gardens". During the USSR period, the terracing was widely spread, but from our point, this kind of farming in mountain territories is low effective. Terraces often may serve as places for gully formation. We recommend 1 - 2 m2 plots for tree planting, which much lessens the erosion process and give good effect. 
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