Investigation of natural resources requires development and improvement of remote sensing methods, to be precise, satellite observations, laser scanning and survey using aerial vehicles; their importance increases with comprehensive research and solving problems of rational use of natural resources and environmental protection. Effective soil productivity management requires an integrated approach including using and developing of GPS (Global Positioning), GIS (Geographic Information Systems), YMT (Yield Monitor Technologies), VRT (Variable Rate Technology), and others. This integrated approach using computer and satellite technologies is called precision agriculture. Precision agriculture system is characterized not by a strictly defined set of methods and technical means; but by a general concept based on the use of satellite positioning technologies (GPS), geographic information systems (GIS), precise mapping of fields and others. Remote sensing technologies for observation the Earth from space are an essential tool for studying and constant monitoring of our planet that helps to effectively use and manage its resources.

This paper presents the review of the current state of agricultural land based on GIS technologies using materials of Earth remote sensing on the example of the foreststeppe zone of Western Siberia which is the most developed and populated territory of this region. We used multispectral images of the Landsat 8 spacecraft (SC) (USA) with a resolution of 30 m per pixel. These images allow monitoring of the Earth's surface every 16th day with a flying-by width of 185 km in nadir. Computer processing of the series of multispectral satellite images (MSI) using the method of synthesizing (superposition of the long and short wavelengths of solar radiation spectrum) was carried out using the licensed software package ENVI 5.0. (produced by ESRI company). During creating electronic cartographic material of the studied area (based on satellite data), a digital basis for agricultural lands was made at first. Digitalization of outdated material was performed using QGis software package (desktop GIS for creating, editing, visualizing, analyzing and publishing geospatial information. It is QGIS Desktop that is often meant by QGIS). For the first time, a spatial-temporal change in the structure of agricultural land of this region over the past twenty-five years was revealed using multi-temporal images made by Landsat 8 SC. Areas were found that have moved from the category of arable land to the fallow one, and were susceptible to flooding. A partial soil survey was conducted in the study area (with sampling for chemical analysis) to establish soil type according to modern classification in order to update soil maps and to create an electronic cartogram showing soil suitability based on their agricultural type. Costeffectiveness of the cluster method for soil and agrochemical survey of agricultural land was calculated.

Modern technologies are not used effectively enough in the current structure of the agro-industrial sector. Remote sensing, as a process of collecting information in a noncontact way, allows providing interested users with objective and detailed information. Currently, it is one of the rapidly developing industries of the fifth technological revolution. The use of aircraft-or satellite-based sensors makes it possible to obtain panoramic images of high resolution. Analysis of images allows us to establish the territory of saline soils, assess the condition of crops and conduct environmental monitoring. The soil layer changes its composition and quality through human activities, which leads to negative consequences. The leading place of atmospheric emissions in the Omsk region belongs to motor vehicles, the number of which is only increasing. Salts of heavy metals (lead and cadmium) settle on soil and plants, accumulating in them over time. At the current state we should talk about local pollution of soils that are located near sources of pollution: various industrial enterprises, thermal power stations and automobile and railway transport.

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One of the most important problems of agriculture under conditions of the soil contamination with radioactive elements is the maximum possible decrease in the supply of these substances to crop production and prevention of their accumulation in the organisms of farm animals. In connection with this, now we have a problem of introducing new technologies and techniques not only in the agrochemical survey of lands but also in the agro-industrial complex as a whole. This article presents experimental data on the concentration of radionuclides 137Cs, 90Sr, 232Th, 226Ra, and 40K in the soils of agricultural enterprise «Druzhba» in the Gorky District of the Omsk Region. The survey was conducted in 2016 on the basis of the Center for Agrochemical Service «Omskiy». The content of 137Cs and 90Sr was shown not to exceed background indices, whereas the use of potassium fertilizers and the composition of soil-forming rocks gives rise in the increase in the content of such radionuclides as 40K, 232Th and 226Ra.