Simulation of environmental risks and capability of land of Southern Dagestan for cultivation of fruit and vegetable crops and grapes

GEOGRAPHICAL INFORMATION SYSTEMS (GIS) are created for summarizing of land and resource information at different levels. A strategy for the integrated analysis of resource potential of lands was developed with the help of international experience of using GIS and modern computer technology [3].

Promising sources of information to create soil-oriented GIS are data of remote survey [1, 2].

The topic of the research is introduction of GIS technologies for inventory of land and resource data, their storage, scientific and applied analysis.

Materials and Methods

Suitability of land for cropping of fruits and vegetables, as well as viticulture has been assessed in 11 administrative districts of the Southern Dagestan, using methods developed by FAO.

A list of degradation types has been made at the first stage. Then algorithms of computer analysis of risk were developed and processed using ALES (Automated Land Evaluation System), the results of which were visualized using GIS; in ALES user-created evaluation algorithms are presented in the form of so-called Tree of Decision-making (TDM). It is a multivariate graph system which includes the entire set of properties and their gradations. Final evaluation rating or class is provided at the end of each “branch” of TDM. Then, a tabular database of evaluated land with its actual property values is entered in ALES. The system processes the input data and generates an integral estimate of land allotments. Results of the analysis are in tabular form or style suitable for use in GIS.

Results

During 2008, in accordance with the appropriate orders of the Government of the Republic of Dagestan, as well as under the Law of the RD “On the status and boundaries of municipalities in the Republic of Dagestan” the land with the total area of 1,409 hectares has been removed from the category “agricultural” and transferred to expand settlements.

Table 1. Distribution of agricultural land and settlements per district of the Russian Federation as of January 1, 2008

Assessment of land suitability for vegetable growing, fruit growing and wine growing given the location on the territory of the Southern Dagestan is based on the principle of searching the more environmentally friendly and the east-cost scenario, the land use system. To this end, suitable and at the same time minimally environmentally risky crop industries have been determined. In other words the best (but not necessarily optimal) type of land-use has been identified for any land plot.

A scenario of crop zoning has been developed within this model which minimized the costs for both addressing the environmental risks, and optimizing limit properties of land. It emerged that land unsuitable for any analyzed type of industry, i.e. 61.05…71.27% of the total land area, is the land of Agulsky, Akhtynsky, Dokuzparinsky, Kurakhsky and Rutulsky districts. The remaining portion of the land is more or less favorable and environmentally safe for one or even several types of industry.

Then, a search of the most appropriate types of industries for each elementary land plot has been conducted without taking into account the degree of suitability and environmental unsafeness.

Areas which could potentially be occupied by the analyzed types of industries have been calculated within the developed model (Table 2) up to 40 % - commercial horticulture, about 30 – viticulture, and 35% - olericulture.

Table 2. Evaluation of the suitability of land for the conduct of vegetable and fruit growing and viticulture in the Southern Dagestan

We have mapped the optimal (for the model) distribution of industries, indicating which land will use the resource potential as fully as possible and with minimal environmental risks.

Such a distribution of industries in many cases may require additional investment to maintain the stability of landscapes, overcoming the effects of limiting factors and some environmental risks.

Restoring soil quality is a very costly, time consuming and sometimes impossible process. There are 10 types of degradation: water erosion and deflation; resalinization; desertification; flooding; packing; thermokarst; soliflucation; degradation of surface soil horizons (caused by deforestation) and their biogenic horizons as a result of forest fires; chemical pollution.

Types of soil degradation that could potentially occur in a particular area depend on the specific use of land and natural conditions. When using land for growing plants in Southern Dagestan we’ve considered water erosion, re-salinization and waterlogging (overdamping) of soils, and their repacking (including destroying) as major types of potential soil degradation.

Results of the environmental risk assessment have been visualized in chart form using geographic information technologies. Most of the environmental risks are associated with the ability to enhance the processes of soil erosion. Almost half of land in Southern Dagestan is exposed to extremely high risks, and only 8 ... 11% of territory has the minimum ranking score.

Maps of integral assessment of environmental risks have been built for each sector. In addition, according to the rule of “maximum”, each of elementary parts за the region (pixel on the map) has been attributed the maximum of the overall ratings of assessment of individual types of degradation risks using a scale expressed in fraction units, and the maximum rating values corresponds maximal environmental risks.

Thus, a specific type of land use would be the least cost, most productive and most environmentally friendly with the full correspondence of land resource potential.