ISSN 2079-0961, Arid Ecosystems, 2011, Vol. 1, No. 2, pp. 74–82. © Pleiades Publishing, Ltd., 2011. Original Russian Text © G.S. Kust, S.Yu. Rozov, G.V. Stoma, P.V. Andreev, 2011, published in Aridnye Ekosistemy, 2011, Vol. 17, No. 2(47), pp. 5–17. 74 INTRODUCTION The literature of the last 20–30 years on the influence of irrigation on chernozems mainly indicates the unfa- vorable consequences that cause salinization, alkalina- tion, degradation of structural properties of humus hori- zons, etc. These processes lead to the degradation of soils of irrigated massifs and their subsequent abandonment and retirement (Irrigated Chernozems, 1989). In addi- tion, the object of our studies has functioned under a var- iously intensive irrigation regime for over 35 years, and in recent years the irrigated areas have even been expanded after they were abandoned in the 1990s for economic rea- sons. Although the soil cover in this area contains solon- chak and solonetz soils, and the irrigation system does not have an artificial drainage network, the stable recur- ring salinization and alkalination of soils is not recorded in the irrigated plots by the data of hydromeliorative monitoring; however, local salinization features are observed even in the humic horizons of soils. The pedogeochemical indication of features and causes of stable operation of these “successful” agricultural land- scapes is of special interest from the perspective of sus- tainable land use in southern Russia. OBJECTS AND METHODS The object of our study is the Privolzhskaya Irriga- tion System (PIS) and the adjoining territories (the total area is about 30 000 ha). In a broad sense, the PIS territory is located within the watersheds between the valleys of the Volga, Bolshoi Irgiz, and Yeruslan rivers and occupies a transitional position from the cher- nozem steppe to the dry steppe. The main part of the PIS lies in the interfluves of the small Bolshoi Kara- man and Malyi Karaman rivers. Irrigation is per- formed mainly by sprinkling using circular-type Fre- gat devices. The relief of the plot in question was formed as a result of the active accumulation erosion activity of the Volga River and its tributaries during the Neogene–Quaternary period. The valley of the Volga River exhibits here the modern bottomland and five over-bottomland terraces. The plot under study lies in four of them: the first one is the Upper Khvalynsk (Sarpinskaya) terrace, the second is the Middle Khvalynsk terrace, the third is the Early Khvalynsk terrace, and the fourth is the Khazar terrace. Except for the Middle Khvalynsk terrace, which is traced as a band from 0.5 to 4 km along the valley of the Malyi Karaman River and in the upper reaches of the Bolshoi Karaman River, the soil-forming rocks are represented mainly by alluvial sandy loams and loamy soils with particular interlayering and spatial heterogene- ity that is typical of bottomland and delta deposits. The Middle Khvalynsk deposits are of marine genesis. They mostly include clays, and heavy- and medium-loamy soils (Grozdova and Savel’ev, 1974). SYSTEMATIC STUDY OF ARID TERRITORIES Pedogeochemical Indication of Sustainable Land Use at the Privolzhskaya Irrigation System (Saratov Region) G. S. Kust a , S. Yu. Rozov b , G. V. Stoma b , and P. V. Andreev b a Institute of Ecological Soil Science, Lomonosov Moscow State University, Leninskie Gory Moscow, 119991 Russia b Soil Science Faculty, Lomonosov Moscow State University, Leninskie Gory Moscow, 119991 Russia e-mail: gkust@yandex.ru Received December 8, 2010 Abstract—Soil cover and landscape-geochemical features of the Privolzhskaya irrigation system (Saratov Volga) are described. The sustainable functioning of this irrigation system in the conditions of the absence of artificial drainage is noted that is explained as a result of the specifics of geomorphologic structure of the area within the ancient flood plain and deltaic landscapes of former Volga river and its tributaries. A number of assumptions are made about the role of paleo features of local landscapes in the redistribution of ground and infiltrated flow from irrigated lands. In particular, the assumption that ancient bottoms of estuaries and lagoons, composed of marine clays and overlapped with latest loamy deposits are acting as natural interme- diate reservoirs of drainage waters. The phenomenon of “red spot” on multispectral (3–5–7 channels) Land- sat images is described, presumably associated with the additional soil moistening in the zone of lateral sub- surface migration of infiltrated irrigation water. Keywords: pedogeochemical indication, sustainable land use, irrigated chernozems. DOI: 10.1134/S2079096111020065