Climate change (CC) may pose a challenge to agriculture and rural livelihoods in Central Asia, but in-depth studies are lacking. To address the issue, crop growth and yield of 14 wheat varieties grown on 18 sites in key agroecological zones of Kazakhstan, Kyrgyzstan, Uzbekistan and Tajikistan in response to CC were assessed. Three future periods affected by the two projections on CC (SRES A1B and A2) were considered and compared against historic ((1961-1990) figures. The impact on wheat was simulated with the CropSyst model distinguishing three levels of agronomic management. Averaged across the two emission scenarios, three future periods and management scenarios, wheat yields increased by 12% in response to the projected CC on 14 of the 18 sites. However, wheat response to CC varied between sites, soils, varieties, agronomic management and futures, highlighting the need to consider all these factors in CC impact studies. The increase in temperature in response to CC was the most important factor that led to earlier and faster crop growth, and higher biomass accumulation and yield. The moderate projected increase in precipitation had only an insignificant positive effect on crop yields under rainfed conditions, because of the increasing evaporative demand of the crop under future higher temperatures.However, in combination with improved transpiration use efficiency in response to elevated atmospheric CO 2 concentrations, irrigation water requirements of wheat did not increase. Simulations show that in areas under rainfed spring wheat in the north and for some irrigated winter wheat areas in the south of Central Asia, CC will involve hotter temperatures during flowering and thus an increased risk of flower sterility and reduction in grain yield. Shallow groundwater and saline soils already nowadays influence crop production in many irrigated areas of Central Asia, and could offset productivity gains in response to more beneficial winter and spring temperatures under CC.Adaptive changes in sowing dates, cultivar traits and inputs, on the other hand, might lead to further yield increasesi.

IntroductionAs a natural system, each terrain has important properties: self-organization, self-regulation, and selfrenewal -all of which facilitate sustainable development of an ecosystem and its ability to resist degradation and crisis processes. Sustainability of terrain is associated with the ability of its components to conserve their structure and function under external influences [1].At present, the impact of anthropogenic factors often exceeds maximal permissible limits, destroying natural ecosystems. First of all, land degradation results in expanded water and wind erosion, reduction of groundwater level, pollution, water logging and salinity of irrigated and non-irrigated soils [2]. Especially in arid regions where productivity of agricultural production is dependent on land irrigation, and soils are mostly subjected to salinity. The following six groups of degradation have been outlined in the World Atlas of Desertification [3]: water erosion, wind erosion, soil fertility decreases, salinization, Pol. J. Environ. Stud. Vol. 25, No. 6 (2016), 2469-2475 Original Research Dynamics of Soil Salinity in Irrigation AbstractThe analysis has been conducted of possibility of determining the extent of soil salinity by indirect and direct decoding of satellite images Pleiades 1A / 1B (in the year of survey) and LANDSATTM (archive). It was found that indirect decoding of salinity based on spectral char-acteristics of vegetation images is strongly dependent on crop growth phase (period of shoot-ing). LANDSAT archive images with normalized soil salinity index (NDSI) allow to develop salinity maps and soil salinity dynamics maps at semi-quantitative level. Based on computer analysis of LANDSAT images it was determined that soil salinity at study object during the pe-riod from 1987 to 2014 has increased due to significant decrease of the area of non-saline soil by 41.5% and increasing of the areas of low and moderately saline soils by 34.9%, also regions with heavily saline soils at 6.6% of total surveyed area have been detected, which previously were absent.

In arid and semi-arid zones, atmospheric dust of different origins influences soil chemistry and plant biomass composition. Thus, studies on plant accumulation of heavy metals and rare earth elements (RREs) should include some assessments of potential eolian deposition. Here, we proposed the use of fractionation of metals in soils as an indirect method to assess potential atmospheric dust input to metal content in plant biomass. Our research was performed on individuals of Tamarix spp. growing on saline automorphic and hydromorphic soils in Kazakhstan. Studied soils could be, in general, classified as polluted, especially in industrial areas of Karaganda and Chromtau. However, concentrations of heavy metals and RREs in biomass remained low, as most of the studied elements were present in plant-inaccessible forms. Nevertheless, we recorded a high accumulation of Cd in biomass (70% of this element present in soils as plant-inaccessible fractions), which indicates the impact of Cd atmospheric deposition.

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Possibilities to use the archive images obtained by Landsat TM5 in different years have been comprehensively analyzed with the aim at recognizing the soils with different salinity degree. Special approaches were proposed to study the dynamics of saline soils by using the satellite imagery. Based upon a computer analysis of the information transmitted by Landsat in 1987-1988 and 2009-2010 as well as the data of field soil survey, it seemed reasonable to identify changes in the area of such soils in Shauldersk irrigated massive (the South-Kazakhstan region, Republic of Kazakhstan). It was concluded that the share of saline soils revealed an increase at the studied territory within the period from 1987 to 2010.