[Gaseous Nitrogen Emission from Soil After Application of NH4+-N Loaded Biochar].

To safely and effectively transfer NH4+-N from eutrophic water to soil, biochar was applied to adsorb NH4+-N from wastewater, and this NH4+-N loaded biochar (N-BC) was subsequently used as a soil amendment. Understanding the influence of N-BC on N2O-N emission and NH3-N volatilization is important for both decreasing the application of chemical fertilizers and reducing gaseous nitrogen loss from soil. In this study, experiments were conducted in soil columns with four treatments, namely CK (no fertilizer), NPK (chemical fertilizer), N-BC+PK (NH4+-N loaded biochar+chemical fertilizer), and BC+NPK (biochar+chemical fertilizer). Compared to both the NPK and BC+NPK treatments, N-BC+PK significantly reduced the cumulative N2O-N emissions and NH3-N volatilization, as well as the total gaseous nitrogen loss from the soil (P<0.05). Relative to NPK and BC+NPK, cumulative N2O-N emissions decreased by 33.62% and 24.64%, cumulative NH3-N volatilization decreased 70.64% and 79.29%, and the cumulative total gaseous nitrogen loss decreased by 64.97% and 73.75%. In particular, BC+NPK significantly enhanced the cumulative NH3-N volatilization. Furthermore, the N2O-N emission flux and NH3-N volatilization rate were significantly positively correlated with the NH4+-N concentration, NO3--N concentration, and pH of soil (P<0.01). Overall, using NH4+-N loaded biochar can significantly decrease N2O-N emissions and NH3-N volatilization, relative to the traditional application combining biochar and chemical fertilizer. This research provides solid theoretical support and data for the application of NH4+-N loaded biochar in soil, to reduce gaseous nitrogen loss.

Antiperovskite Chalco-Halides Ba3(FeS4)Cl, Ba3(FeS4)Br, and Ba3(FeSe4)Br with Spin Super-Super Exchange.

Perovskite-related materials have received increasing attention for their broad applications in photovoltaic solar cells and information technology due to their unique electrical and magnetic properties. Here we report three new antiperovskite chalco-halides: Ba3(FeS4)Cl, Ba3(FeS4)Br, and Ba3(FeSe4)Br. All of them were found to be good solar light absorbers. Remarkably, although the shortest Fe-Fe distance exceeds 6 Å, an unexpected anti-ferromagnetic phase transition near 100 K was observed in their magnetic susceptibility measurement. The corresponding complex magnetic structures were resolved by neutron diffraction experiments as well as investigated by first-principles electronic structure calculations. The spin-spin coupling between two neighboring Fe atoms along the b axis, which is realized by the Fe-S···S-Fe super-super exchange mechanism, was found to be responsible for this magnetic phase transition.

[Regional characteristics of ion concentration in glacial snowpits over the Tibetan Plateau and source analysis].

The characteristics of ion concentration were studied in snowpit samples collected from the GRHK glacier, the XDKMD glacier and the YZF glacier over the Tibetan Plateau. Samples of snowpits in these three glaciers were analyzed by ion chromatography and ion sources were also explored by correlation analysis. The results indicated that the concentration of Ca2+, Mg2+, Na+, Cl- and SO4(2-) increased from the GRHK glacier to the XDKMD glacier and to the YZF glacier, suggesting that the terrestrial matter were major origin from the south to north over the Tibetan Plateau. The concentration of Cl-, Na+ and SO4(2-) in YZF glacier was higher by many times than GRHK glacier and XDKMD glacier, Perhaps mainly come from the evaporation of salt lake and the weather of mineral salts in the Qaidam Basin. The sources of NO3-, K+ and NH4+; were complicated and it is not obvious for the indication of environment.

[Bacterial diversity recovered from Qiyi Glacier and runoff, Qilian Mts].

Abundance and species diversity of bacteria were investigated respectively by epifluorescence microscope, the culture method and the analysis of 16S rDNA genes, with snow and runoff samples from Qiyi Glacier in the Qilian Mts. According to the results, the total microbial cells and bacterial CFU range from 10(3) to 10(5) cells x mL(-1) and 0-600 cfu x mL(-1), respectively. The 16S rDNA gene of 22 bacterial isolates recovered from snow and runoff samples belong to following groups: Bacteroidetes, Actinobacteria, Firmicutes and alpha, beta, gamma-Proteobacteria. Based on their 16S rRNA sequences, Bacteroidetes forms the largest cluster in terms of abundance (80% of all isolates) and Pedobacter and Pseudomonas form the dominant genera in terms of abundance (90% of all isolates). Compared with bacteria revealed from ice and snow in Qinghai-Tibet Plateau, South Pole and North Pole which have been reported, the bacteria belonging to Pantoea, Providencia, Terrabacter, Aerococcus and Oxalobacteraceae are especially exist in Qiyi Glacier as far as we know.

[Hydrochemical characteristics and evolution of runoff at Qiyi glacier, Qilian Mts].

Glacier ice, supraglacier stream water, ice-marginal stream water, proglacier stream water samples were collected at Qiyi glacier located in central part of Qilian Mountain 2006-06 - 2006-07. Major ions concentration, pH and EC were analyzed. The results indicate that pH varies from 8.05 to 8.79, and EC 32.4 - 134.4 microS cm(-1). The order of major ions concentration in differed water is: supraglacier stream water< ice-marginal stream water < proglacier stream water. Meanwhile, hydrochemical characteristics vary from HCO3(-) -Ca(2+) to (HCO3(-) + SO4(2-))-(Ca(2+) + Mg(2+)). Major ions,almost in all samples; HCO3(-) > SO4(2-) > Cl(-) > NO3(-), Ca(2+) > Mg(2+) > Na(+) > K(+) mainly comes from carbonate weathering,and some is from sulfate dissolution. Concentrations of Mg(2+) and K(+) increase quicker than Na(+) and Ca(2+) in proglacier stream and ice-margin stream that is inverse to their abundance in crust. The spatial characteristic of ions concentration is controlled by the process of water-rock and temporal change is hydrological factors.