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12345674389A5 12345 1 WIND EROSION INTENSITY DETERMINATION BY AIRBONE CAPTURE Lenka LACKÓOVÁ, Tomáš URBAN1 1 Slovak University of Agriculture, Faculty of Horticulture and Landscape Engineering, Department of Landscape Planning and Ground Design ABSTRACT The airborne capture method determines the intensity of wind erosion using soil particle catchers which trap soil particles transported by the wind at different heights above the soil surface in the specific conditions affecting the occurrence, process and intensity of wind erosion. For soil particle capture in the field we designed the first prototype of soil particle catcher. In the field measurements we tried to trap the moving soil particles, due to wind, through the first prototype soil particle catcher.The duration of each measurement was always 60 minutes. The calculation of the quantity of particles captured per unit area is very simple because the width of the entrance is 5 cm. Multiplying the width and length of erosive surface in the wind direction we can calculate the area of wind erosion surface.The results of the wind erosion events analysis show that during the monitored period effective erosive winds lasted a total of 58 hours. The most frequent average hourly wind speed ranged from 5.0 to 5.9 ms-1 and the period of occurrence lasted a total of 28 hours. The maximum average minute wind speed reached 12.3 ms-1 and a maximum gust of wind was 17.3 ms-1. Key words: airboone capture, soil particle, wind erosion INTRODUCTION Soil degradation due to erosion is the irreversible loss of the surface, the most fertile layer of soil; loss of humus, organic matter, nutrients, reduction in soil biological activity and the overall deterioration of the natural processes in land use and crop production as well as decrease in production capacity in the affected soil (Demo et al. 2000). .If a longperiodof droughtoccurs at this time and is followed by a period ofeitherintenseprecipitation(water erosion) orhigh intensitywinds(winderosion) erosion will occur (Halva, Dudek, 2003). The process of wind erosion (aeolian) is via the loss of the soil surface by mechanical wind forces (abrasion), moving and transporting the soil particles (aggregates) by wind (deflation) and depositing them elsewhere (accumulation). Wind erosion is a physical phenomenon and it is directly influenced by the physical properties of the soil, by kinetic energy, and by many other factors (Stre8anský, 1993). The potential vulnerability of the agricultural soils of 3731 1 12345674389A5 12345 1 Slovakia was calculated by the Research Institute for Soil Science and Conservation, Bratislava. About 3.2% of agricultural land is subject to high or extreme vulnerability to wind erosion. Despite the small size, the effects are significant, so it is necessary to geographically locate the most affected area and suggest erosion measures (Muchová, Vanek, 2009). The process of wind erosion causes damage to agricultural land especially erosion of soil particles, fertilizers, seeds and pesticides. It exposes plant roots and eroded soil particle damage young plant shoots in particular. (Pokrývková, Kalúz, 2012).the resultantamount ofsoilerosionisaccurately determinedgeographically (Kliment, Kliment, 2012). MATERIAL AND METHODS The airborne capture method determines the intensity of wind erosion using soil particle catchers which trap soil particles transported by the wind at different heights above the soil surface in the specific conditions affecting the occurrence, process and intensity of wind erosion. For soil particle capture in the field we designed the first prototype of soil particle catcher (fig. 1). The apparatus consists of a tapered entrance through which the circulating air flows into the body of the soil particle catcher, which absorbs the kinetic energy of wind. Inside the soil particle catcher are the three filters that trap the soil particles. The entrance section consists of a hole, which is 5 cm wide and 20 cm high. The narrow input section gradually expands and connects to the body of the contraption, which is 25 cm wide and 20 cm high. The soil particle catcher is 130 cm long. Figure 1 First model of soil particle catcher (Urban, 2011) RESULTS In the field measurements we tried to trap the moving soil particles, due to wind, through the first prototype soil particle catcher. During these measurements, we also tested the efficiency and the efficacy of the soil particle catcher to capture moving particles. The catcher was freely situated on the soil surface in the prevailing wind direction and it trapped the moving soil particles up to a height of 20 cm above the soil surface. The duration of each measurement was always 60 minutes. The calculation of the quantity of particles captured per unit area is very simple because the width of the entrance is 5 cm. Multiplying the width and 3741 1 12345674389A5 12345 1 length of erosive surface in the wind direction we can calculate the area of wind erosion surface. Model field in the Mo2enok Region The evaluated soil unit in modeled field is 37. It is mainly a medium grade with typical chernozems and carbonate on loess, for unit 31 - black soils typical and black soils gleyed, medium and heavy, the loess slope and clay, and for 17 - black chernozems, mainly carbonate, medium. According to the analysis of the BPEJ maps no soil susceptible to wind erosion occurs, there is a more vulnerable soil type; black chernozem (HPJ 16) (fig. 2). On 08.04.2011, during the second wind erosion event between 16:00 and 17:00 (measurement duration - 60 minutes) at an average wind speed of 5.7 ms-1 1,722 grams of eroded soil was trapped in the soil particle catcher, which equates to 1299.6 kg.ha-1.hour-1 of soil loss (soil particle catcher 5 cm wide with a north-western wind erosion surface length of 265 m) On 13.4.2011, the second measurement at the same location during the fifth wind erosion event between 10:00 and 11:00 at an average wind speed of 5.6 ms-1 364.4 grams of eroded soil was trapped equating to 275.0 kg.ha-1.hour-1 of soil loss. A third measurement was performed between 11:00 to 12:00 the same day in the same place at an average speed of 4.3 ms-1. In soil particle catcher 199 grams of soil was trapped which represents soil erosion of 150, 2 kg. ha-1.hour-1. The measurement site is shown in fig 29. Analysing data (average minute data on wind speed and direction), provided by SHMÚ (from the nearest meteorological station Nitra - Janíkovce), we found that in the area in the period from the 5th to 15th April 2011 there were a total of wind erosion events. As an effective erosive wind in our case we chose a wind speed which is higher than the critical wind speed for loam soil by Pasák (1964). The recalculated critical speed at the height at which the meteorological station measures is > 4.5 ms-1. The following tables show the average hourly rate of effective erosive winds and their duration according different wind erosion events. Figure 2 Map of present condition of fields 8 and 9 and BPEJ Figure 3 Map of soil deflation and accumulation 3751 1 12345674389A5 12345 1 CONCLUSION We performed field measurements of soil erosion with soil particle catchers designed by us. We tested the first prototype of such a device which proved to be fit for purpose with easy conversion of captured soil particles to quantities lost across the erosion area. During the first week of April in 2011, we measured the intensity of soil erosion on black chernozems with soil particle catcher. At modeled soil unit we performed a couple of measurements in order to determine soil erodibility during a 60 minute period, the increase of soil erosion with increasing erosive surface length as well as researching the soil loss at different heights. The results of the wind erosion events analysis show that during the monitored period effective erosive winds lasted a total of 58 hours. The most frequent average hourly wind speed ranged from 5.0 to 5.9 ms-1 and the period of occurrence lasted a total of 28 hours. The maximum average minute wind speed reached 12.3 ms-1 and a maximum gust of wind was 17.3 ms-1. REFERENCES DEMO, M. et al. 2000. Regula3né technológie v produk3nom procese po1nohospodárskych plodín. Nitra: SPU, 2000. 667 s. ISBN 80-7137-732-5. FUSKA, J. Digitálny model reliéfu dna malej vodnej nádrže - podporný nástroj pre hodnotenie objemu vodnej nádrže. In: Transport vody, chemikálií a energie v systéme pôda rastlina – atmosféra. Bratislava : Ústav hydrológie SAV, 2012. ISBN 978-80-89139-26-2 -S. 171-177. HALVA, J., DUDEK, M. 2003. Ohrozenos5 katastrálneho územia Doj3 veternou eróziou. In: Science of the youth 2003 : 1st international scientific conference. V Nitre: Slovenská po1nohospodárska univerzita, 2003. ISBN 80-8069-262-9. HALVA, J., KLIMENT. M. 2009. Vplyv presnosti digitálneho modelu reliéfu na modelovanie eróznej ohrozenosti. In: Zborník z konferencie GIS Ostrava 2009, VŠB TU Ostrava. 2009 KLIMENT, T., KLIMENT, M. 2012. Environmentálne geopriestorové informácie získané v prostredí" mainstream" webu [elektronický zdroj]. In: Krajinné inžinierstvo-trendy a perspektívy. -- 1 CD-ROM ([220] s.). Nitra: Slovenská po1nohospodárska univerzita, 2012. -[7] s. ISBN 978-80-552-0961-6 MUCHOVÁ, Z – VANEK, J. 2009. Metodické štandardy projektovania pozemkových úprav. Nitra: SPU v spolupráci s Ministerstvom pôdohospodárstva, 2009. 397s. ISBN 978-8-5520267-9. POKRÝVKOVÁ, J., KALÚZ, K. 2012. Zníženie úrod vybraných plodín vplyvom emisií. In: Ekonomika po1nohospodárstva. -- ISSN 1335-6186. Vol. 12, no. 1 (2012), s. 90-101 STRE4ANSKÝ, J. 1993. Veterná erózia pôdy. Nitra: VŠP, 1993. 66 s. ISBN 80-7137-094-0. 3761 1 12345674389A5 12345 1 Acknowlegment: This paper was published with the financial support VEGA 1/0050/12 “Wind erosion determination with mathematic modelation” Contact address: Ing. Lenka Lackóová, PhD., Slovak University of Agriculture in Nitra, Faculty of Horticulture and Landscape Engineering, Department of Landscape Planning and Ground Design, e-mail: [email protected] 3771 1