– 109 – Acta fytotechn. zootechn., 17, 2014(4): 109–114 Vladimír Šimanský*, Nora Polláková, Samuel Halmo: Soil crust in agricultural land © Slovak University of Agriculture in Nitra Faculty of Agrobiology and Food Resources, 2014 http://www.fapz.uniag.sk/ DOI: 10.15414/afz.2014.17.04.109–114 1. Introduction The physical properties of a soil have much to do with its suitability for the many uses to which man puts it. The rigidity and supporting power, both wet and dry, the freedom of drainage, moisture-storage capacity, plasticity, ease of penetration by roots, aeration, and retention of plant nutrients are all intimately connected with the physical condition of the soil (Millar et al., 1962). Soil crust is a major structural feature of surface soil and one of the most important physical properties (Graef and Stahr, 2000). Formation of soil crust is mainly influenced by salts of Na + , Ca 2+ , soil organic matter and particle-size distribution. The soil crust is not formed in the soils with content of sand more than 60 % (Špička et al., 1964). Lal and Shukla (2004) mentioned three categories of soil crust. The physical and biological crusts are dominant especially in the semi-arid and arid regions (West, 1990; Hawkes and Flechtner, 2002). Chemical crust is formed due to salt incrustations on soil surface. Biological or micro-biotic crusts are primarily formed by algal growth. Such crusts are extremely hydrophobic, and drastically reduce the rate of water infiltration into soil. Physical crust is formed due to alternation in structural properties of the soil, and may be structural or depositional. Structural crust is formed due to the disruption of aggregates by raindrop impact and physiochemical dispersion of soil clays (McIntyre, 1958). Nowadays, soil physical properties are more important than ever before in sustaining agricultural productivity. It was recorded great shrinking of global arable land area per capita. For example, in last years, according to the Soil Science and Conservation Research Institute, the annual average soil loss was around 1000–5000 hectares in Slovakia. Unfortunately, similar situation is currently observed in the whole European Union and world. When consider sustainable soil management, the conservation and maintenance of favourable physical properties is very important (Kotorová and Šoltýsová, 2011). The purpose of this paper was to evaluate soil crust parameters in selected arable soils of Slovakia. We quantified (1) the effects of soil types, added farmyard manure, and crops on the formation of soil crust, and (2) the influence of selected soil properties on crust formation. 2. Material and methods 2.1 Site 1 First study area is located in south-west part of Tribeč Mountain. Soil samples were taken from a productive vineyard from an ongoing experiment with different management practices at Nitra-Dražovce (Nitra wine- growing area). The mean annual rainfall is 550 mm and the mean annual temperature is ≥10 °C. The soil was formed on limestone and dolomite. According to the Soil crust in agricultural land Vladimír Šimanský*, Nora Polláková, Samuel Halmo Slovak University of Agriculture in Nitra, Slovak Republic The effects of exogenous and endogenous factors on the formation of soil crust in arable soils of Slovakia were evaluated. Soil samples for determination of selected soil organic matter parameters, physical properties – particularly soil crust, were collected from localities Dražovce, Bučany and Jacovce (different soil/climatic conditions at each site) in spring 2012. The results showed that organic fertilization decreased the formation and thickness of soil crust. According to the susceptibility to crust formation, studied soils were ranged in a decreasing order: Calcaric Chernozem > Stagni-Haplic Luvisol > Rendzic Leptosol > Mollic Fluvisol. The thickness of soil crust were significantly depended on cultivated crops. The most favourable value of index of crusting was calculated in the field with grown spring barley, following by pea < oil rape < winter wheat. We determined negative correlation between clay and index of crusting (r = -0.880, P ≤0.01). Higher formation of soil crust was determined in soil with higher content of water-stable micro-aggregates (r = 0.799, P ≤0.05) and smaller size fractions of water-stable macro-aggregates in size fractions 0.25–0.5 mm (r = 0.865, P ≤0.01). Higher content of soil organic matter of rather stabile than labile form resulted to reduction of crust thickness as well as decreased the index of crusting. Keywords: index of crusting, soil structure, soil organic matter, soil types, organic fertilization, crops *Correspondence: Vladimír Šimanský, Slovak University of Agriculture in Nitra, Faculty of Agrobiology and Food Resources, Department of Soil Science, Trieda A. Hlinku 2, 949 76 Nitra, Slovakia, e-mail: Vladimir. Simansky@uniag.sk Original Paper