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Öğe Agricultural sustainability in Turkey: Integrating food, environmental and energy securities(Wiley, 2002) Evrendilek, F; Ertekin, CAgricultural production in Turkey is not sustainable due to degradation and loss of croplands, rapid population growth, and inequitable economic growth (poverty and overconsumption). Degrading land uses and management practices disturb the life-supporting biogeochemical cycles within croplands and between croplands and natural ecosystems by increasing emissions of greenhouse gases (GHGs: CO2, CH4, N2O, CFCs, and tropospheric O-3), pollution of water, soil and air, loss of soil organic matter and biodiversity, erosion, salinization and desertification. Sustainability-oriented management practices in croplands include maintenance of soil organic matter by conservation tillage and residue management, windbreaks, selection of crops ecologically adapted to local climate regimes, efficient crop rotation, enhancement of agrobiodiversity (e.g. intercropping and agroforestry), and adoption of proper drainage techniques. Implementation of these preventive and mitigative measures necessitates internalization of ecological principles into agricultural policy and management processes. This study explores the opportunities and limitations of agricultural sustainability in Turkey in a holistic manner. A multiple linear regression (MLR) model was developed to relate CO2 emissions to energy intensity (energy use/gross domestic product), affluence (gross domestic product/population) and population growth. Our MLR model with a high R-2 of 97 per cent revealed that stabilization of human population growth, and increasing energy efficiency in economic growth are essential to decreasing GHG emissions and enhancing environmental quality. Copyright (C) 2002 John Wiley Sons, Ltd.Öğe Assessing the potential of renewable energy sources in Turkey(Pergamon-Elsevier Science Ltd, 2003) Evrendilek, F; Ertekin, CTo meet Turkey's growing energy demand, the installed electric power capacity of 27.8 GW in 2001 has to be doubled by 2010 and increased fourfold by 2020. The difference between Turkey's total primary energy supply (TPES) of from its own sources and total final consumption (TFC) is projected grow from 1 quad (1.06-2.06) in 1999 to 5.71 quads (2.79-8.5) in 2020 (1 quad = 293.071 TWh). Turkey's limited amount of fossil fuels has a present average ratio of proved reserves of 97.38 quads to production rate of 3.2 quads yr(-1) of about 30 years. Turkey's reliance on fossil fuel-based energy systems to meet the growing demand is most likely to exacerbate the issues of energy insecurity, national environmental degradation, and global climate change in increasing proportions. Economically-feasible renewable energy potential in Turkey is estimated at a total of ca. 1.69 quads yr(-1) (495.4 TWh yr(-1)) with the potential for 0.67 quads yr(-1) (196.7 TWh yr(-1)) of biomass energy, 0.42 quads yr(-1) (124 TWh yr(-1)) of hydropower, 0.35 quads yr(-1) (102.3 TWh yr(-1)) of solar energy, 0.17 quads yr(-1) (50 TWh yr(-1)) of wind energy, and 0.08 quads yr(-1) (22.4 TWh yr(-1)) of geothermal energy. Pursuit and implementation of sustainability-based energy policy could provide about 90 and 35% of Turkey's total energy supply and consumption projected in 2010, respectively. Utilization of renewable energy technologies for electricity generation would necessitate about 23.2 Mha (29.8%) of Turkey's land resources. (C) 2003 Elsevier Science Ltd. All rights reserved.Öğe Changes in soil organic carbon and other physical soil properties along ajacent Mediterranean forest, grassland, and cropland ecosystems(Academic Press Ltd- Elsevier Science Ltd, 2004) Evrendilek, F; Celik, I; Kilic, SCultivation, overgrazing, and overharvesting are seriously degrading forest and grassland ecosystems in the Taurus Mountains of the southern Mediterranean region of Turkey. This study investigated the effects of changes on soil organic carbon (SOC) content and other physical soil properties over a 12-year period in three adjacent ecosystems in a Mediterranean plateau. The ecosystems were cropland (converted from grasslands in 1990), open forest, and grassland. Soil samples from two depths, 0-10 and 10-20cm, were collected for chemical and physical analyses at each of cropland, open forest, and grassland ecosystems. SOC pools at the 0-20 cm depth of cropland, forest, and grassland ecosystems were estimated at 32,636, 56,480, and 57,317 kg ha(-1), respectively. Conversion of grassland into cropland during the 12-year period increased the bulk density by 10.5% and soil erodibility by 46.2%; it decreased SOM by 48.8%, SOC content by 43%, available water capacity (AWC) by 30.5%, and total porosity by 9.1% for the 0-20 cm soil depth (p < 0.001). The correlation matrix revealed that SOC content was positively correlated with AWC, total porosity, mean weight diameter (MWD), forest, and grassland, and negatively with bulk density, pH, soil erodibility factor, and cropland. The multiple regression (MLR) models indicated that any two of the three ecosystems and one of the two soil depths accounted for 86.5% of variation in mean SOC values ((P<0.001). (C) 2004 Elsevier Ltd. All rights reserved.Öğe Changing global climate: Historical carbon and nitrogen budgets and projected responses of Ohio's cropland ecosystems(Springer, 2004) Evrendilek, F; Wali, MKAs the evidence of global climate change continues to mount, its consequences for cropland productivity assume particular significance. Against the backdrop of past agricultural practices, simulation models offer a glimpse into the future, showing the effect of temperature changes on crop production. In this study, we first quantified the carbon (C) and nitrogen (N) budgets of Ohio's cropland ecosystems using inventory yield data of corn for grain, oat, and all wheat for the period 1866-1996 and soybean for the period 1924-96. Then we explored the responses of Ohio's continuous soybean croplands to changes in temperature, carbon dioxide (CO2) concentration, initial soil organic C and N (SOC-N) pools, soil texture, and management practices by developing a simple cropland ecosystem model (CEM) and performing a long-term sensitivity analysis. Finally, CEM simulations were evaluated against independent observations of SOC values (0-19 cm) averaged over 470 northwest Ohio sites between 1954 and 1987 under conventional tillage and rotations of corn-soybean-winter wheat by using the historical yield data (r(2) = 0.8). The C contents per hectare of crop harvests increased by 178% for oats, 300% for corn for grain, and 652% for all wheat between 1866 and 1996 and by 305% for soybean between 1924 and 1996. Ohio croplands acted as C-N sources, releasing average net ecosystem emissions (NEE), including the removal of harvested C-N, of 4,598 kg CO2 ha(-1) and 141 kg N ha(-1) in 1886 and 205 kg CO2 ha(-1) (except for the corn-for-grain cropland) and 39 kg N ha(-1) in 1996. The continuous corn croplands continued to become a C sink, sequestering 255 kg C ha(-1) in 1996. Results of the sensitivity analysis for Ohio's continuous soybean croplands revealed that the SOC pool increased by 6.9% and decreased by 7.5% in response to a doubled CO2 concentration and a temperature increase of 2.8degreesC over 100 years, respectively. The sequestration potential of the SOC pool increased by 6.5% at a rate of 24.6 kg C ha(-1) y(-1) for the same period with finer soil texture (loam to silty clay loam). The shift from conventional to conservation residue practice led to an 11% increase in the steady-state SOC storage at a rate of 42 kg C ha(-1) y(-1) for 100 years.Öğe Developing a suitability index for land uses and agricultural land covers(Springer, 2005) Kiliç, S; Evrendilek, F; Senol, S; Çelik, IThis study was aimed at determining the land-use and land-cover (LULC) potentials of a southeastern Mediterranean area (Antakya, Turkey) of 36 816 ha for a total of 23 different LULC types: nine horticultural crops, nine field crops and five non-agricultural lands. Land evaluation was carried out by using a combination of SENOL Land Evaluation System and ILSEN computer program adapted to Turkey from FAO land evaluation principles. Our assessment resulted in the identification of nine physiographical units, 27 different soil series, and 110 land mapping units. Nearly 49% of the study area was determined as suitable for agricultural land cover types, and 35% for non-agricultural land use types. A map showing potential suitability of LULC was derived for the study area. The quantification of LULC suitability assists decision makers in ensuring that lands are used according to their capacities to satisfy human needs for present and future generations, thus sustaining ecological and economic productivity of natural resources.Öğe Environmental monitoring of land-use and land-cover changes in a Mediterranean region of Turkey(Springer, 2006) Kilic, S; Evrendilek, F; Berberoglu, S; Demirkesen, AUnprecedented rates of human-induced changes in land use and land cover (LULC) at local and regional scales lead to alterations of global biogeochemical cycles. Driving forces behind LULC changes mainly include rapid growth rates of population and consumption, lack of valuation of ecological services, poverty, ignorance of biophysical limitations, and use of ecologically incompatible technologies. One of the major ecological tragedies of the commons in a Mediterranean region of Turkey is the loss of Lake Amik at the expense of increasing the area of croplands, which used to provide vital ecosystem goods and services for the region. In this study, we aimed at quantifying the effects of past land-use transitions on soil organic carbon (SOC) pools (0-20 cm) in a Mediterranean region of 3930 km(2), between 1972 and 2000. LULC changes were quantified from a time series of satellite images of Landsat-MSS in 1972, Landsat-5 TM in 1987, and Landsat-7 ETM+ in 2000 using geographic information systems. The study showed that the increase in croplands between 1972 and 1987 took place at the expense of the irreversible losses of Lake Amik and its related wetlands of over 53 km(2). In the period of 1972 to 2000, croplands, settlements, and evergreen forests increased by 174%, 106%, and 14%, respectively. The increase in settlements occurred mostly to the detriment of croplands. Given the average rates of all the land-use transitions, and associated changes in SOC density for the study region of 3930 km(2), total SOC pool was estimated to decrease by 14.1% from 130.1 Mt in 1972 to 111.7 Mt in 2000.Öğe Identification of ecologically significant habitats for urban nature conservation: A case study in Turkey.(Triveni Enterprises, 2003) Evrendilek, FGiven the rapid urbanization of Turkey, sustained productivity of natural resources should. be an integral part of any urban development policy. The biogeochemical cycles and ecosystem services link urban and rural ecosystems. It is, therefore, essential that ecologically significant habitats along urban-rural continuum be protected to secure public and environmental health. This necessitates their identification and the establishment of administrative and legal foundations for urban nature conservation in the management of urban habitats. should,be established Ecological analysis of urban habitats of Karsiyaka led to the identification of 19 ecologically significant habitats. Nature conservation priority was rated, using rarity, species richness, stratification, site age, and area of the habitats. Ecologically significant habitats made up about 54 ha of the total urban green space of 289 ha in Karsiyaka. The total number of plant species was estimated to be 273.Öğe An inventory-based carbon budget for forest and woodland ecosystems of Turkey(Royal Soc Chemistry, 2004) Evrendilek, FEnvironmental monitoring of national-level comparisons of CO2 emissions is needed to quantify sources and sinks of carbon ( C) in national ecosystems. In this study, a national forest inventory database was used to estimate the past and current pools and fluxes of C in deciduous and coniferous forest and woodland ecosystems (20.7 x 10(6) ha) of Turkey. Growing C stock was 12.63 t C ha(-1) in 1960 and 16.55 t C ha(-1) in 1995. Total C store in the whole live woody biomass was estimated at 22.77 t C ha(-1) in 1996. The total flux of C from the atmosphere into the forest and woodland ecosystems driven by primary productivity was about 1.46 t C ha(-1) (or 30.2 Mt C) in 1996. The estimated net release of C from the forest and woodland ecosystems of Turkey to the atmosphere was about 1.34 t C ha(-1) ( or 21.5 Mt C) in 1996. When C released was taken into account, net ecosystem sequestration (NES) resulted in 0.12 t C ha(-1) per year. Such analytical tools as national forest C budgets are needed to improve our preventive and mitigative strategies for dealing with global climate change.Öğe Modelling long-term C dynamics in croplands in the context of climate change: a case study from Ohio(Elsevier Sci Ltd, 2001) Evrendilek, F; Wali, MKA simple dynamic model (CBUDGET) was developed to quantify long-term carbon (C) dynamics in croplands. By using independent datasets (on continuous wheat) from the Waite Permanent Rotation Trial (Australia) and from Northwest Ohio, the tests of its performance resulted in R-2 values of 0.85 and 0.80, respectively, between observed and simulated values. Our model suggests that the rate of residual C addition into the soil is the primary factor that controls soil organic carbon (SOC) storage for Ohio croplands under continuous corn, wheat and oats for the period 1866-1996 and continuous soybean for the period of 1924-1996. The interaction of CO2-fertilization and a temperature increase of 0.5 degreesC decreased mean SOC levels for the selected crops over the same periods. A multiple linear regression model (MLR) relating carbon dioxide (CO2) emissions to population growth, affluence and energy intensity with an R-2 of 0.99 indicates the significance of underlying causes of anticipated climate change. The MLR model thus serves to capture a more complete picture of anthropogenic sources of global climate change than considering agricultural activities only in exploring locally and regionally mitigative and preventive measures towards global climatic stability. (C) 2001 Elsevier Science Ltd. All rights reserved.Öğe Spatial and temporal variations in diurnal CO2 fluxes of different Mediterranean ecosystems in Turkey(Royal Soc Chemistry, 2005) Evrendilek, F; Ben-Asher, J; Aydin, M; Çelik, IDiurnal rates of net CO2 assimilation (P-N) and soil respiration (R-h) in the summer were measured in six Mediterranean ecosystems through an automatic continuous monitoring system. The six sites include a typical evergreen Pinus pinea L. forest with two co-occurring sclerophyllous shrubs (Pistacia terebinthus L. and Phillyrea latifiolia L.), citrus (Citrus Union L.), corn (Zea mays L.), cotton (Gossypium hirsutum L.), soybean (Glycine max L.) and vineyard (Vitis vinifera L.). All six sites exhibited similar behaviour in that low soil water availability and high evaporative demand not only depressed P-N and R-h, rates, but also changed the diurnal time course of their peak rates. Except for P. terebinthus and corn, P-N rates of all the species peaked in the morning (7:30-9:30), and R-h, rates in all the sites were higher during the night than during the day (p < 0.05). Mean rates of net ecosystem emission (NEE) Of CO2 to the atmosphere were highest (-23.9 mu mol CO2 m(-2) s(-1)) in the corn site and lowest (-0.6 mu mol CO2 m(-2) s(-1)) in the vineyard site. On average, all six ecosystems were a net source of CO2 to the atmosphere, due to R-h effluxes exceeding P-N rates. Net CO2 assimilation and R-h explained 25% (for corn) to 87% (for citrus) of the diurnal fluctuations of the atmospheric CO2 concentration. Multiple linear regression (MLR) models accounted for 42% (P. pinea) to 95% (cotton) of diurnal variations in P-N rates and 30% (forest) to 92% (citrus) of diurnal variations in R-h rates (p <= 0.001). The dependence of diurnal P-N and R-h rates on water vapour pressure deficit and soil water deficit for dry and hot summer days appeared to be major and needs to be re-examined for biogeochemical models of climate change effects on CO2 dynamics of Mediterranean ecosystems.Öğe Yield and fruit quality of watermelon (Citrullus lanatus (Thumb.) Matsum. & Nakai.) and melon (Cucumis melo L.) under protected organic and conventional farming systems in a Mediterranean region of Turkey(Taylor & Francis Ltd, 2004) Çürük, S; Sermenli, T; Mavi, K; Evrendilek, FProtected conventional and organic farming systems for watermelon and melon were compared over a two-year period in the Mediterranean Amik plain of southern Turkey. Yield, fruit quality and growth responses of the vegetable crops were measured and compared as a function of conventional management, and three composted sheep-cattle manure treatments of 6 kg m(-2), 12 kg m(-2) and 18 kg m(-2). On average, total and marketable yields of watermelon and melon grown organically under low plastic tunnels showed a two-fold increase under the organic treatments of 12 kg m-2 and 18 kg m(-2) relative to the protected conventional management system (p < 0.05). There was no significant difference in watermelon and melon yields between the manure application levels of 12 and 18 kg m(-2). There were significant changes in mean fruit weight and width between the control and the manure level of 18 kg m(-2) for watermelon and in mean stem diameter between the control and the manure levels of 12 and 18 kg m(-2) for melon (p < 0.05). Multiple linear regression (MLR) models accounted for about 49% and 52% of variations in marketable yields of melon and watermelon as a function of the control and the manure levels of 12 and 18 kg m(-2), respectively. The findings indicate that protected organic watermelon and melon systems in this Mediterranean region can produce more total and marketable yields than protected conventional systems. Protected organic farming systems can assist in compliance with maximum residue limits imposed on exported agricultural commodities and reduce dependency on industrial fertilizers as well as emissions of fertilizer production-related greenhouse gases.
