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  • Küçük Resim
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    Biomass, carbon and nitrogen dynamics of multi-species riparian buffers within an agricultural watershed in Iowa,USA
    (Kluwer Academic Publishers, 2003) Tüfekçioğlu, Aydın; Raich, J.W.; Isenhart, T.M.; Schultz, R.C.
    This study was conducted to determine biomass dynamics, carbon sequestration and plant nitrogen immobiliza- tion in multispecies riparian buffers, cool-season grass buffers and adjacent crop ?elds in central Iowa. The seven-year-old multispecies buffers were composed of poplar (Populus × euroamericana ‘Eugenei’) and switch- grass (Panicum virgatum L.). The cool-season grass buffers were dominated by non-native forage grasses (Bro- mus inermis Leysser., Phleum pratense L. and Poa pratensis L). Crop ?elds were under an annual corn-soybean rotation. Aboveground non-woody live and dead biomass were determined by direct harvests throughout two growing seasons. The dynamics of ?ne (0–2 mm) and small roots (2–5 mm) were assessed by sequentially col- lecting 35 cm deep, 5.4 cm diameter cores (125 cm deep cores in the second year) from April through Novem- ber. Biomass of poplar trees was estimated using allometric equations developed by destructive sampling of trees. Poplar had the greatest aboveground live biomass, N and C pools, while switchgrass had the highest mean aboveground dead biomass, C and N pools. Over the two-year sampling period, live ?ne root biomass and root C and N in the riparian buffers were signi?cantly greater than in crop ?elds. Growing-season mean biomass, C and N pools were greater in the multispecies buffer than in either of the crop ?elds or cool-season grass buffers. Rates of C accumulation in plant and litter biomass in the planted poplar and switchgrass stands averaged 2960 and 820 kg C ha-1 y-1, respectively. Nitrogen immobilization rates in the poplar stands and switchgrass sites averaged 37 and 16 kg N ha-1 y-1, respectively. Planted riparian buffers containing native perennial species therefore have the potential to sequester C from the atmosphere, and to immobilize N in biomass, therefore slow- ing or preventing N losses to the atmosphere and to ground and surface waters.
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    Coruh river dam projects and their ecological impacts
    ([y.y.], 2008) Tüfekçioğlu, Aydın; Altun, Lokman; Kalay, Hasan Zeki; Schultz, R.C.; Yılmaz, Murat
    Coruh river starts from Mescit Mountains of Bayburt, Turkey and reaches Black Sea in Batum, Georgia. The total length of the river is around 431 km. and 410 km of it in the boundries of Turkey and the remaining 21 km in the Georgia. The annual discharge of the river is 6.3 billion cubic meter. Coruh is the fastest running river of the Turkey with an elevational difference of 1420 m. It carries 5.8 million cubic meter of sediment each year. Ten dams are planned to construct on the main river while 21 planned to construct on the branches of the river. They will generate 10.6 billions kWh energy per year. Seven of these dams are located in the vicinity of Artvin. Construction of new roads have also started to solve the transportation problem of the area because some part of the roads are going to be covered by the water. Road construction will damage the forests of the valley due to high slope in the area. Fish species living in the river such as Salmo trutta labrax, Salmo trutta lcapius, Cypirinus carpio, Barbus cycloepsis and Silurus glanis are going to lose their habitat. The region is rich in endemism. The number of endemic species is 119 for Artvin and some of them grows in the main valley of Coruh river. They will lose their habitat after the construction of the dams.
  • Küçük Resim
    Öğe
    Soil respiration within riparian buffers and adjacent crop fields
    (Kluwer Academic Publishers, 2001) Tüfekçioğlu, Aydın; Raich, J.W.; Isenhart, T.M.; Schultz, R.C.
    3 We quantified rates of soil respiration among sites within an agricultural 4 landscape in central Iowa, USA. The study was conducted in riparian cool-season grass 5 buffers, in re-established multispecies (switchgrass + poplar) riparian buffers and in 6 adjacent crop (maize and soybean) fields. The objectives were to determine the 7 variability in soil respiration among buffer types and crop fields within a riparian 8 landscape, and to identify those factors correlating with the observed differences. Soil 9 respiration was measured approximately monthly over a two-year period using the soda- 10 lime technique. Mean daily soil respiration across all treatments ranged from 0.14-8.3 g 11 C m-2 d-1. There were no significant differences between cool-season grass buffers and 12 re-established forest buffers, but respiration rates beneath switchgrass were significantly 13 lower than those beneath cool-season grass. Soil respiration was significantly greater in 14 both buffer systems than in the cropped fields. Seasonal changes in soil respiration were 15 strongly related to temperature changes. Over all sites, soil temperature and soil moisture 16 together accounted for 69 % of the seasonal variability in soil respiration. Annual soil 17 respiration rates correlated strongly with soil organic carbon (R =0.75, P<0.001) and fine 18 root (<2 mm) biomass (R=0.85, P<0.001). Annual soil respiration rates averaged 1140 C 19 m-2 for poplar, 1185 g C m-2 for cool-season grass, 1020 g C m-2 for switchgrass, 750 g 20 C m-2 for soybean and 740 g C m-2 for corn. Overall, vegetated buffers had significantly 21 higher soil respiration rates than did adjacent crop fields, indicating greater soil biological 22 activity within the buffers.