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Öğe Changes in soil quality parameters after a wildfire in Gelibolu (Gallipoli) National Park, Turkey(Parlar Scientific Publications (P S P), 2005) Ekinci, H; Kavdir, YThe objective of this study was to determine the influence of forest wildfires that occurred 1994 in Gelibolu (Gallipoli) National Park, Turkey, on some physical, chemical and biological properties of soils. Soil samples were collected from five different locations as replicates from both burned and nearby unburned sites. Results showed that available phosphorus and potassium content, pH, and electrical conductivity of burned soils were higher than those of unburned counterparts. On the other hand, aggregate stability, hydraulic conductivity, total porosity, soil water content, cation exchange capacity, total nitrogen, urease activity, and microbial biomass carbon values of burned soils were lower than those of unburned ones. The mean soil organic carbon values were 2.94% for burned and 5.01% for unburned soils, whereas those of microbial biomass were 1.2 mg C g soil(-1) and 1.69 mg C g soil(-1). Aggregate stability values were found to be 88.32% and 94.44% (P < 0.05), and urease activities were 185 mg kg(-1) 2-h(-1) and 366 mg kg(-1) 2-h(-1) (P < 0.01) for burned and unburned soils samples, respectively. This research showed that negative effects of fire still remain in the soil even after 8 years and recovery of soil health was very low.Öğe Gis monitoring and evaluation of nitrogen pollution in the waters of Troy, Turkey(Parlar Scientific Publications (P S P), 2005) Özcan, H; Kavdir, YTroy in Turkey is not only important from an archeological point of view, but also from an ecological perspective as well. The waters of Troy have been used as drinking source for the birds and other animals and are still used as an irrigation source by farmers. This study was carried out to monitor and determine the amounts of NO3-N, NH3-N and NO2-N ions and their spatial and temporal changes from December 2002 to September 2003 in the Troy water resources. Water samples were collected from 25 sampling points at each sampling time. Samples were preserved according to specific test requirements and immediately analyzed for NO3-N, NH3-N, and NO2-N ions using a LaMotte smart colorimeter. Global positioning system (GPS) was used to determine the coordinates of the sampling points. Producing maps and statistical analyses' results indicate that both ammonia and nitrate nitrogen concentrations started to increase after May in all water resources. These changes were attributed to land use types and crop growing periods in the area. Nitrate concentration ranged from 0 to 45 mg L-1, ammonia from 0 to 118 mg L-1 and nitrite from 0 to 3.5 mg L-1. One well, two drainage canals, and two river samples have.clearly elevated nitrate levels without elevated chloride, and this suggests fertilizers as source of nitrate in water. There are positive and significant linear relationships between nitrate and chloride concentrations in two wells suggesting that the water is being impacted by domestic sewage.Öğe Soil aggregate sequestration of cover crop root and shoot-derived nitrogen(Springer, 2005) Kavdir, Y; Smucker, AJMCover crop roots and shoots release carbon (C) and nitrogen (N) compounds in situ during their decomposition. Depending upon the season, these C and N compounds may be sequestered, the C may be respired or the N may be leached below the root zone. A field study was established to identify the contributions of cover crop root and shoot N to different regions within aggregates in the A(P) horizon of a Kalamazoo loam soil. Fall-planted rye plants (Secale cereale L.) were labeled the next May with foliar applications of solutions containing 99% atom ((NH4)-N-15)(2)SO4. Isotopic enrichment of soil aggregates ranging from 2.0 to 4.0, 4.0-6.3 and 6.3-9.5 mm across was determined following plant residue applications. Concentric layers of aggregates were removed from each aggregate by newly designed meso soil aggregate erosion (SAE) chambers. Non-uniform distributions of total N and recently derived rye N in soil macroaggregates, across time, suggested that the formations and functions of macroaggregates are very dynamics processes and soil aggregates influence where N is deposited. Early in the season, more 15 N migrated to the interior regions of the smallest aggregates, 2-4 mm across, but it was limited to only surfaces and transitional regions of the larger aggregates, 6.3-9.3 mm across. Exterior layers of aggregates between 6.0 and 9.5 mm retained 1.6% of the N-derived from roots in July 1999, which was three times more than their interior regions. This was slightly greater than the % N-derived (from shoot). One month later, as the maize root absorption of N increased rapidly, % Nderived front roots and % Nderived from shoot were nearly equal in exterior layers and interior regions of soil aggregates. This equilibrium distribution may have been from either greater diffusion of N within the aggregates and/or maize root removal form aggregate exteriors. Results supported that most of roots grew preferentially around surfaces of soil aggregates rather than through aggregates. Cover crop roots contributed as much N as cover crop shoots to the total soil N pool. Subsequent crops use N from the most easily accessible zones of soil structure, which are surfaces of larger soil aggregates. Therefore maintaining active plant roots and aggregated soil structure in the soil enhances N sequestration and maximize soil N availability. These studies suggest that the rapid and perhaps bulk flow of soil N solutions may bypass many of the central regions of soil aggregates, resulting in greater leaching losses.Öğe Soil aggregate stability and 13C CP/MAS-NMR assessment of organic matter in soils influenced by forest wildfires in Canakkale, Turkey(Elsevier, 2005) Kavdir, Y; Ekinci, H; Yüksel, O; Mermut, ARThe impact of forest fire on soil quality is not well appreciated. This study investigated the influences of forest wild fires that occurred 12, 8, 2 years and 2 weeks before the time of sampling on the composition of the forest floor organic matter by comparing total carbon (C) and total nitrogen (TN), composition of organic functional groups as determined by C-13 CP/MAS-NMR and soil aggregate stability of unburned and burned forest floor in Canakkale, Turkey. Fire altered soil organic matter composition and reduced organic C content of surface (0-5 cm) soil. The C-13 CP/MAS-NMR analyses confirmed that the forest soils exposed to fires 12, 10 and 2 years before the time of sampling had higher potential for humification than unburned control soils. However, soils exposed to the fire 2 weeks before the time of sampling became more humified than unburned control soils. Carbohydrate contents of the recently burned soils were distinctly lower than those of the control soils. This is expected, as burning would reduce fresh litter which contains labile and easily decomposable materials. There was 20% decrease in 1990, 52% in 1994, 43% in 2000 and 11% in 2002 of soil organic carbon values of burned soils, compared to unburned forest floor. Fire also reduced the stability of soil aggregates by 1-16%. It was found that carbohydrate content of soil organic matter was directly related (r(2)=0.92) to the stability of soil aggregates but not to the total amount of organic matter. The very high correlation coefficient suggests that carbohydrate C functional group plays an important role in the stabilization of soil aggregates. (c) 2005 Elsevier B.V. All rights reserved.Öğe Specific contributions of decaying alfalfa roots to nitrate leaching in a Kalamazoo loam soil(Elsevier, 2005) Kavdir, Y; Rasse, DP; Smucker, AJMAlfalfa (Medicago sativa L.) contributes 430 million kg N year(-1) to the US Corn-Belt soils, according to a 1991 survey. Minimizing leaching losses from these very large N inputs requires a better understanding of the specific root dynamics that relate to the shoot-borne nitrates which have been reported to develop throughout many soil profiles. The objective of the present study was to determine the impact of decaying alfalfa roots on nitrate inputs to soils and on soil hydraulic conductivity properties which affect nitrate leaching. An experiment was initiated in 1994 and data for this report were taken from research on a Kalamazoo loam soil (fine-loamy, mixed, mesic Typic Hapludalf) at the KBS/LTER (long-term ecological research) site in southwestern Michigan, during the period from 1996 through 1997. Soil extractable nitrate (NO3-N) and ammonium (NH4-N) were monitored to soil depths of 150 cm and soil soluble NO3-N and NH4-N were monitored by suction lysimeters to the depth of 65 cm. Saturated hydraulic conductivity (K-sat) of soil was measured by the double-ring infiltrometer method. Following glyphosate termination of the alfalfa stands, nitrate-N released from mineralized alfalfa roots plus shoots totaled 75 kg ha(-1). Alfalfa roots generated 36 kg ha(-1) and alfalfa shoots generated 39 kg ha(-1) which accumulated in the Ap horizons from April to July in 1997. The presence of decaying alfalfa roots in the profile quadrupled Ksat values as compared to bare fallow soils. Nitrates released from decomposing alfalfa roots combined with root-enhanced hydraulic conductivities dramatically increased NO3-N leaching following the termination of alfalfa stands. NO3-N leaching to deeper horizons approached 83 kg ha(-1) in root treatments and 144 kg ha(-1) in the root plus shoot treatments during the period from April to December, following alfalfa termination. Our data suggest that under temperate climate such as that of Michigan, groundwater contamination by nitrates can be reduced by terminating alfalfa stands immediately before spring-planting of the subsequent row crop, which can absorb the large quantities of N leaking from decomposing shoots and roots of the legume. (c) 2005 Elsevier B.V. All rights reserved.Öğe The effect of municipal waste compost on physical characteristics of clay soils(Parlar Scientific Publications (P S P), 2004) Yuksel, O; Kavdir, Y; Bahtiyar, MThe objective of this study was to determine the effect of different concentrations of municipal waste compost (0, 40, 80, 120 and 160 t ha(-1)) on soil physical properties of vertisol and non-calcareous brown soils. According to the results, the waste compost application to the soil increased its porosity and reduced the bulk density. In general, adding waste composts to soils positively affected the soil physical properties of non-calcareous brown soils. However, addition of waste compost to vertisol soils with high clay contents did not significantly change the soil aggregate stability. The best compost application levels among applied doses were 120 and 160 t ha(-1).Öğe The impact of an open waste disposal site on soil and groundwater pollution(Inderscience Enterprises Ltd, 2004) Baba, A; Kavdir, Y; Deniz, OA study has been carried out of a waste disposal site, located in the valley of a small creek, 3 km south of Canakkale city centre. The surface area of the site was around 10000 square metres, and the total amount of waste deposited at the site since 1990 was approximately 100000 tons. The major risks of the dump are its closeness to the university campus area to the south, the airport to the north, and residential areas encroaching towards the dump site. The nuisance caused by odour is high. The waste pile emplaced at the head of the tributary stream has caused channelling of the leachate to the creek, which is eventually washed towards the agricultural fields. The field investigation included surface geological, hydrogeochemical and geochemical studies. Water samples were collected at 11 points. Three observation wells were dug in front of the open waste disposal site. Soil samples from these observation wells were collected at 30, 70 and 150 cm depths, and some heavy metals were analysed. The concentrations of lead, copper and zinc in soil at the depth of 150 cm decreased with distance from the waste disposal site. Hydrogeochemical data analysis gave similar results.
