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M.Eren Öztekin , Mahmut Dingil , Levent Atatanır Department of Soil Science, Faculty of Agriculture, Çukurova Universty, Adana, Turkey Abstract In this study a spectroradiometer( EXOTECH 100 BX-TS) was used to measure reflectance values of 5 different soil series. The samples were taken from soil surface. Physical and chemical analyses were done in order to determine which soil properties are effecting the reflectance values from soils. Some chemical and physical properties of soils are affecting reflectance values significantly. Iron oxid is directly effects the reclectance values. Results have show that increas in reflectance values are affected by the carbonate contents. Organic matter contents had no significant affect on the reflectane values due to very low amounts. Introduction The aim of the whole studies done from the past to present and also for the future is just for the well being of the humans population. It is obligated to know the capacity the uses of these sources. In the recent years it is agreed that the research by using satellite technolgy is not completely urable without the support of field measurments. Meanwhile the field measurments increase in importance with the cooperation of satellite technology. Today spectroradiometers are specially used for the field measurments. Most of the spectroradiometer measurments has the same spectral fields as the satellites. The multiband receivers used in the satellites and also for the field measurment devices, the working principle depends on sunlight,received from the materials. Moreover that, we could imagine the exact time for examining the field materials with satellites by the cooperation of the field measurments. The reclection values of the materials counted from earth help us to identify them when recevied with remote sensing. Another use of the field measurment system is in agriculture mostly for the crop yield and agricultural area identification.. A study which was done on this area, an Exotech Model 20C spectroradiometer was used out door under solar illumination to obtain spectral response from dry and moistened field plots with and without corn residue cover, representing the different soils. Results indicate that laboratory measured spectra of moist soil are directly proportional to the spectral response of that same field measured moist bare soil over 0,52-to 1,75 µm wavelength range (Stoner E.R et all).There are a lot of factors effecting soil reclectance values. The presence of some soil constituents , for example iron oxides, limestone, organic matter and water content is revealed by their typical effect on color (Taylor 1982 and Bigham and Ciolkosz 1993). Soil organic matter content and the composition of organic constituents are known to have a strong influence on soil reflectance. A general observation has been that as organic matter content increases soil reflectance decreases throughout the 0.4-2.5 µm wavelength range (Hoffer and Johannsen 1969). Baumgardner et al(1970) found that organic matter content drops below 2.0 % it becomes less effective in masking the effects on reflectance of other soil constituents. In this study, reflectance values of the soil surface was determined by a spectroradiometer (EXOTECH 100 BX-TS). The reflectance values are discussed in relation to physical and chemical soil properties . Materials and Methods Soil survey of the study area were completed by Çukurova Universty Agricultural Faculty Soil Science Department ( Dinç et al. 1988).The study area was choisen becauseof wide distrubition of similer soils between Şanlıurfa and Mardin where placed on Harran Plain. The reflectance values of the soil series surfaces were determined by a radiometer. These series are Karabayir, Sirrin, Kap, Gulveren and Irice. Radiometric mesurments were determined 800-1000 o'clock because of approximete time of satellite pass over the study area. The radiometer 100BX-TS s/n 3668 was used to determined reflectance values of the soil Bandpass of the radiometer is show in Table 1. It was calibrated a table which covered BaSO4. Reflection values were similar the bands of Landsat TM 1,2,3 and 4 . Soil samples were taken between 10-15 cm from soil surface. The soil texture analysis were done according to the hydrometer method (Bouyoucos, 1951); CaCO3 % with the Scheibler Calcimeter (Schlichting ve Blume, 1966); Organik Matter (O.M.) contents according to Allison (1965); For the Fe % colorimetric orthofenentrolin method was used (Jackson 1979)  A board which covered BaSO4 was used for the calibration of the Spectroradiometer. Right position of the coordinate points are very important therefore GPS was used to determine the coordinates. The avarege error of the GPS localization points is approximetly 10 m. Results and Discussion Some properties of the soils which are measured are given below. Karabayir Series : This soil was formed on Basalt parent material and lies on flat ground. There are 10-30 cm diameter basalt stones on the surface. The texture of the series soils is clayey throughout the profil. The area which was measured is the phases of the Karabayır series. General properties of that soils are 3-6 % slope, moderate deep(60-90cm) moderate stony(10-50%). Sirrin Series : This soil was formed on mud flow flat parent material(coluvial), generally they are very deep, and contains few 0,5-1cm diameter stones on the surface. The texture of the series soils is clayey throughout the profile. The area where the measurment was taken is the phases of the Sırrın soil series. The area has 3-6 % slope. Kap Series : This soil was formed on Miocene limestones parent material, moderately deep generally flat, and contains few 3-10 cm diameter stones throughout profile. The texture of the series soil is clayey. The area where the measurment was taken is the phases of the Kap soil series. The area has 3-6 % slope, soil depth very shallow(0-30cm) and stony(2-10 %). Gulveren Series : The soil was formed on limestone parent material , moderately 4-10 cm diameter stones on surface.The texture of the series soil is clayey and so calcerious. The area where was the measurment was taken is the phases of the Gulveren soil series. The area has 3-6 % slope, deep 90-120cm İrice Series : The soil was form on Bajada, lies on flat ground. The texture of the series soil is clayey and calcerious. The area where was the measurment was taken is the phases of the Irice soil series. The area has 0-2 % slope. The Chemical and Physical analyses of the series were given Table 2.  Reflectance values of the all soils are series taken in 25 m intervals in which 8 or 9 values are registered the exact reflectance values of the soils were determined by the average of reflectance values. Reflectance values of the soils from different bands are given bellow (Table3).  The reflectance values of the Karabayir series are lower than the other series which was formed on Basalt parent material. The color of the series 5 YR according to Munsell (Figure1).  % CaCO3 Contents also effects reflectance values. Increas in CaCO3 contents increase the reflectance values. Irice and Sirrin series has high CaCO3 contents therefore show higher reflectance values (Figure 2). The texture of the soil is known to have significant influence on reflectance from soils. The effect of the texture on the reflectance values from soils could not be determined because there was no significant differences between the texture of the soil series when the measurments were taken (Figure 3).  Conclusion In this study, Organic matter content and Fe % content have not significantly affected the reflectance values of the soil because the percentage of these material are very low. Increas in CaCO3 contents increased the reflectance values. The texture is a significant factor that influences the reflectance but the ratio of the clay, sand and loam of the series are similar. For this reason the texture of soils which were measured could not be used for discusions on the reflectance curves. References . Dinç, U., Şenol,S., Sayın, M., Kapur, S. Güzel, N., Derici, R., Yeşilsoy, M.Ş.,Yeğingil,İ., Sarı, M., Kaya, Z., Aydın,M., Kettaş, F., Berkman, A., Çolak, A.K., Yılmaz, K., Tunçgöğüs, B., Çavuşgil, V.,Özbek, H., Gülüt, K,Y., Karaman, C., Dinç, O., Öztürk, N & Kara, E,E.,. 1988 Güneydoğu Anadolu Bölgesi Toprakları(GAT) I. Harran Ovası . Türkiye Bilimsel ve Teknik Araştırma Kurumu Tarım ve Ormancılık Araştırma Grubu Proje No TOAG 534. Tübitak.Ankara . Taylor R. M.,1982 Color in soils sediments. Review.In.Proc Int.Clay Conf. Bologna , Italy Elsevier, Amsterdam pp 705-765 . Bigham,J.M&Ciolkosz,E.J. Editors.,1993 Soil Color Publ No 31 SSSA, Madison WI 159 pp . Bouyoucos, G.J., 1951. A recalibration of the hydrometer method for making mechanical analysis of soil. Agron. Jour. 43, 434-438. . Schlichting, E & Blume, E., 1966. Bodenkundliches Practikum. Verlag Paul Parley, Hamburg und Berlin. . Jackson, M.L., 1979. Soil Chemical Analysis-Advanced Course, 2 nd Ed. Published By the author. University of Wisconsin, Madison .Wis. . Stoner,E.R.,Baumgardner,R.A.,Weismiller,R.A.,Biehl,L.L&Robinson,B.F.,1980. Extension of laboratory measured soil spectra to field conditions. Soil Sci.Soc.Am J 44: 572-574 . Hoffer, R.M., & Johannsen C.J., 1969 In " Remote Sensing in Ecology"(P.L.Johnsen,ed.) pp 1-29. Univ of georgia Press, Athens . Baumgardner, M.F., Kristof, S.J., Johansen, C.J., & Zachary, A.L., 1970. Indiana Acad.Sci proc.79,413-422 . Allison, L.E., 1965. Organic carbon in Methods of Soil Analysis (C.A. Black ed.) Amer. Soc. Agron. Mon. 9., Madison Wis. |