Factors of Soil Genesis of Croatia

Abstract

This chapter describes and illustrates with numerous photos and figures all substantial heterogeneities in the factors of soil genesis: parent rock, climate (including water), relief, and biological factors—natural vegetation, soil micro- and macroflora and fauna. Anthropogenic impacts are an additional and powerful factor in soil genesis that is especially visible in the Adriatic agricultural region. In this region, one finds elements of the past and present in direct contact! Namely, on the one hand there are numerous abandoned terraces, while on the other we see the grinding of hard rocks for the planting of vines. What a pity that the modern generation equipped with powerful engines and money do not respect the hundreds of years of collected experience of our Istrian, Dalmatian, and Island peoples living with karst and knowing how to read the nature of karst! Factors of soil genesis are not usually separate and isolated in terms of their influence. The influence of certain soil factors is only in some cases and at particular stages of evolution seen as pronounced or even dominant, in all other cases they are connected and interdependent. Some authors add time, and vegetation fires, which are particularly frequent in the Adriatic region, to the list of soil genesis factors. The parent substrate is the most influential factor in soil genesis, because the mineral component of the soil originating from it. It may be calcareous, acid, rich or poor in plant nutrients, etc. We can find the same properties in soil, especially in juvenile stages. In the Pannonian region the dominant parent material is of eolian origin—loess and its leached, fluvio-glacially changed forms. In the mountainous region limestone, dolomites and eruptive–metamorphic rocks dominate, and we can also find eolian sediment. But the Adriatic region is completely dominated by limestone and dolomites, creating the basis for the well-known geomorphological and hydrological karst phenomena, and affecting the structures of natural phytocenoses. The data show that limestone and dolomites are the most abundant lithological units and extend over about 40 % of Croatian territory. This is followed by loess, which extends over 19 %, alluvial (Holocene) loams, clay and sand ca. 17 %, Pleistocene loams ca. 7.5 %, marl and limestone ca. 6 %, sandstones ca. 2.5 %, flysch ca. 2.3 %, gneiss, shale, quartz sandstones, and conglomerates ca. 1.9 %, relict red soil ca. 1.3 %, and dolomite about 1.1 % of the total land area of the country. Climatic conditions are also a very powerful factor in all stages of soil genesis. Croatia is geographically situated in the continental part of Europe, and shows the mixed effects of three types of climate: Mediterranean, Mountainous, and Continental, all of which, in interaction with other factors, have a specific influence on soil genesis and properties of the soil cover. Following general natural heterogeneity, the biological factors of soil genesis are also very heterogeneous, especially vegetation. Over the territory of Croatia we find steppe in arid and meadow phytocenoses in humid conditions. But the riches in Croatia are the forest phytocenosis of three vegetation zones: Eurosiberian–North American, Mediterranean, and Altimontane. In the Adriatic karst zone we find maquis (macchia), garrigue, and rocky vegetation as indicators of hydrothermic conditions. We have given special attention as regards soil genesis to anthropogenic influences present for a long time. For example, the Vučedol civilization near Vukovar existed more than 5,000 years ago, at the same time as the first civilizations in Mesopotamia? The people of this civilization lived by agriculture, mostly growing beef cattle. In modern, intensive, market-oriented agriculture economic factors place strong pressure on reducing the number of crops or even applying monoculture adapted to the “lproduction line”. This creates a very efficient and profitable agriculture, but an unstable, artificial, sensitive agroecosystem; the soil becomes exhausted, and its fertility is gradually reduced. Time is an important but passive factor in soil genesis and the time-consuming process of soil formation. Most Croatian soils have been created since the last glaciations, i.e., within a period of about 10,000 years. It is known that during this period we have had significant changes, for example, climatic conditions changed, and they were not as they are in recent times and today. But as much as 48 % of Croatian territory is exposed to surface runoff of different intensities. It is clear that the surface horizon of all soils created by soil genesis may be translocated by water and wind erosion to lower positions, where they remain on slopes, at their foot, or are exposed by a watercourse to alluvial transfer and translocation.