Highlights 22 Systems based on extensive grazing act as net sink for greenhouse gases. 23 Greenhouse gas balance of livestock farming highly depends on precipitation. 24 Livestock farming could be a net sink for greenhouse gases under proper management year-1 (net sink) and -475±144 g CO 2 equiv. m -2 year -1 (net source) for the mowed treatment. 42Net source activity at the mowed treatment was due to its higher herbage use intensity compared 43 to the grazed treatment. At the farm scale the system was estimated to be a net sink for NGHG in
Spatial patterns of ecosystem processes constitute significant sources of uncertainty in greenhouse gas flux estimations partly because the patterns are temporally dynamic. The aim of this study was to describe temporal variability in the spatial patterns of grassland CO 2 and N 2 O flux under varying environmental conditions and to assess effects of the grassland management (grazing and mowing) on flux patterns. We made spatially explicit measurements of variables including soil respiration, aboveground biomass, N 2 O flux, soil water content, and soil temperature during a four-year study in the vegetation periods at grazed and mowed grasslands. Sampling was conducted in 80×60 m grids of 10 m resolution with 78 sampling points in both study plots. Soil respiration was monitored nine times, and N 2 O flux was monitored twice during the study period. Altitude, soil organic carbon, and total soil nitrogen were used as background factors at each sampling position, while aboveground biomass, soil water content, and soil temperature were considered as covariates in the spatial analysis. Data were analyzed using variography and kriging. Altitude was autocorrelated over distances of 40-50 m in both plots and influenced spatial patterns of soil organic carbon, total soil nitrogen, and the covariates. Altitude was inversely related to soil water content and aboveground biomass and positively related to soil temperature. Autocorrelation lengths for soil respiration were similar on both plots (about 30 m), whereas autocorrelation lengths of N 2 O flux differed between plots (39 m in the grazed plot vs. 18 m in the mowed plot). Grazing appeared to increase heterogeneity and linkage of the spatial patterns, whereas mowing had a homogenizing effect. Spatial patterns of soil water content, soil respiration, and aboveground biomass were temporally variable especially in the first 2 years of the experiment, whereas spatial patterns were more persistent (mostly significant correlation at p<0.05 between location ranks) in the second 2 years, following a wet year. Increased persistence of spatial patterns after a wet year indicated the recovery potential of grasslands following drought and suggested that adequate water supply could have a homogenizing effect on CO 2 and N 2 O fluxes.
Az utóbbi időben az atmoszférába irányuló folyamatosan növekvő üvegházhatású gázok kibocsátása fokozott figyelmet érdemel. Míg a talaj felszínéről történő gázemissziót széleskörűen tanulmányozzák, viszonylag kevesen vizsgálják a talajprofilon belül az üvegházhatású gázok transzportját és koncentrációváltozását. Vizsgálatunk célja ezeknek a folyamatoknak a tanulmányozása volt bolygatatlan talajoszlopokban. Mivel a talajlevegő mintavétele gyakran körülményes, különösen vízzel átitatott és nedves talajokban, egy szilikoncsöves talajlevegő mintavevőt fejlesztettünk ki bolygatatlan talajoszlopok számára. Hat bolygatatlan talajoszlopot preparáltunk a Pannon Egyetem Georgikum Mezőgazdaságtudományi Karának keszthelyi tartamkísérleti területének művelés alól kivont részéről. A talajlevegő mintavételezéséhez szilikoncsöveket helyeztünk el a talajoszlop három eltérő mélységében (20, 40 és 60 cm). Mivel a szilikoncső falán keresztül a gázok diffúzióval könnyen átjutnak, a szén-dioxid és dinitrogén-oxid koncentrációját mérni tudtuk. A talajoszlopokba kukoricát vetettünk és a növények növekedése során közel egyenlő időközökben vizsgáltuk a talajgáz összetételét. Míg a CO2koncentrációja a talajmélységgel szignifikánsan változott, addig a N2O eloszlása alig változott. A talajlevegő CO2- és N2O-tartalma időben jelentősen változott. A tenyészidőszak alatt a CO2-koncent-ráció két csúcsot mutatott, ezek közül az első csúcs a 20 cm-es mélységben korábban jelent meg, mint a 40 és 60 cm-es mélységben. A 20 cm-es mélységben a CO2-koncentráció időbeli ingadozása sokkal kisebb volt. A második csúcs után a CO2koncentrációja mind a három mélységben fokozatosan lecsökkent. A N2O-koncentráció egy maximumot mutatott a kísérlet kezdeti szakaszában, ami egybeesett a kezdeti intenzív gyökérnövekedéssel, és feltehetően a talajlégzés általi jelentős O2-fogyasztás miatt növekedett az anaerob talajtérfogat, ami a denitrifikáció fokozódásához vezetett. Ezt követően a N2O-képződés fokozatosan lecsökkent. A talaj gázösszetétel dinamikájában nyomon követhető változások a gyökérlégzés intenzitásával, a talajnedvesség és a hőmérséklet változásával állhattak kapcsolatban, amire közvetett módon a csapadék- és léghőmérséklet adatok alapján következtettünk.
Phytoextraction potentials of two transgenic (TR) poplar (Populus x canescens) clones TRggs11 and TRlgl6 were compared with that of wild-type (WT) following exposure to paraquat, zinc sulfate, common salt and nitric oxide (NO), using a leaf-disc system incubated for 21 days on EDTA-containing nutritive WPM media in vitro. Glutathione (GSH) contents of leaf discs of TRlgl6 and TRggs11 showed increments to 296% and 190%, respectively, compared with WT. NO exposure led to a twofold GSH content in TRlgl6, which was coupled with a significantly increased sulfate uptake when exposed to 10(-3) M ZnSO4. The highest mineral contents of Na, Zn, Mn, Cu, and Mo was observed in the TRggs11 clone. Salt-induced activity of catalase enzyme increased in both TR clones significantly compared with WT under NaCl (0.75% and 1.5%) exposure. The in silico sequence analyses of gsh1 genes revealed that P. x canadensis and Salix sachalinensis show the closest sequence similarity to that of P. x canescens, which predicted an active GSH production with high phytoextraction potentials of these species with indication for their use where P. x canescens can not be grown.
This study measured in situ indoor gamma dose rates in Arıklı village situated near a uranium mineralisation region, evaluated the risks of radiological health hazards and established a hypothetical relationship between these values and building materials using statistical tools. Eberline brand portable type ESP-2 model Na (I) scintillation probe connected detector was used for the measurements in 45 dwellings. Statistics revealed two groups. The first group consists of the dwellings made of bricks or mixed materials both plastered by cement, while the second group represented the dwellings made of Arıklı tuff plastered with soil (modified Arıklı tuff) or cement. For the first and second groups, respectively, the medians of the indoor gamma dose rates were 188.79 and 261.87 nGy/h; for indoor Annual Effective Dose Equivalents (AEDEin) they were 0.93 and 1.28 mSv/h; and for Excess Lifetime Cancer Risks (ELCRin) they were 3.69 and 5.12, respectively. All the values were higher than those of the world averages.
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