[Effect of Biochar on Ammonia Volatilization in Saline-Alkali Soil].

In order to investigate the effect of biochar on NH3 volatilization in saline-alkali soils of the Yellow River Delta, continuous laboratory incubation was conducted. Firstly, the recovery rate of NH3 volatilization by an improved aeration method was determined, the effects of fertilizer particles and aqueous fertilizer solution on NH3 volatilization were then compared. Finally, the effects of biochar species, application amount, and fertilizer type on NH3 volatilization rate and total amount were explored. The results showed that the average recovery rate of NH3 reached 100.30% using ammonium sulfate as the nitrogen source. With the same rate of nitrogen application, the volatilization of NH3 decreased by 60.29% in the treatment with urea as the aqueous solution compared to the treatment with urea particles, and decreased by 61.40% in the treatment with an ammonium sulfate aqueous solution compared to the treatment with ammonium sulfate particles. Compared with the control treatment (without the addition of biochar and with the addition of ammonium sulfate solution), the addition of 0.5% biochar derived from 300℃ rice biochar (RB-300), 600℃ rice biochar (RB-600), 300℃ cotton biochar (CB-300), and 600℃ cotton biochar (CB-600) reduced the total volatilization of NH3 by 18.68%, 16.16%, 9.35%, and 8.26% respectively. The volatilization rate of NH3 was at its highest within two days of fertilization, which accounted for 53.80%-64.02% of the total volatilization. After the addition of the biochar, volatilization of NH3 decreased at first and then increased in proportion to an increase in biochar content. Therefore, adding a small amount of biochar before field fertilization, combined with the integrated management of water and fertilizer, can effectively reduce NH3 volatilization and improve nitrogen use efficiency.

ß-cyclodextrin functionalized biochars as novel sorbents for high-performance of Pb2+ removal.

The aim of this study was to synthesize the functionalized biochars with ß-cyclodextrin (ß-CD), compare the two kinds of adsorption capability, and try to explore the possible mechanism for the adsorption Pb2+ by ß-CD functionalized rice straw and palm biochars in the aquatic environment. The performance of the functionalized biochars was matched against the activated and raw biochars. Rice straw biochar loaded with ß-CD performed better than functionalized palm biochar with the adsorption capabilities of 130.60 mg/g and 90.30 mg/g at Pb2+ concentration of 3000 mg/L and 2000 mg/L, respectively. Maximum adsorption capability of functionalized rice straw and palm biochars from the Langmuir isotherms were all fitted out to be 131.24 mg/g and 118.08 mg/g for Pb2+. Kinetics and thermodynamics are combined to investigate the Pb2+ removal by the two functionalized biochars, e.g, Pb2+ is mainly removed by chemical process for functionalized palm biochar, whereas by both physical and chemical factors for functionalized rice straw biochar.

[Effects of elevated ozone concentrations on enzyme activities and organic acids content in wheat rhizospheric soil.] / O3æµ“åº¦å‡é«˜å¯¹å°éº¦æ ¹é™ åœŸå£¤é ¶æ´»æ€§å’Œæœ‰æœºé ¸å«é‡çš„å½±å“.

The elevated concentration of tropospheric ozone (O3) is an important global climate change driver, with adverse impacts on soil ecological environment and crop growth. In this study, a pot experiment was carried out in an open top chamber (OTC), to investigate the effects of elevated ozone concentration on soil enzyme activities (catalase, polyphenol oxidase, dehydrogenase and invertase), organic acids contents (oxalic acid, citric acid and malic acid) at different growth stages (tillering, jointing, heading and ripening stages) of wheat, and combined with the rhizospheric soil physicochemical properties and plant root characteristics to analyze the underlying reasons. The results showed that, elevated ozone concentration increased soil catalase, polyphenol oxidase, dehydrogenase and invertase activities at wheat ripening period to different degrees, with the effects on the activities of catalase and polyphenol oxidase being statistically significant. At the heading stage, activities of dehydrogenase and invertase were significantly increased by up to 76.7%. At the ripening stage, elevated ozone concentration significantly increased the content of citric acid and malic acid and redox potential (Eh) in rhizospheric soil, but reduced soil pH, electrical conductivity, total carbon and nitrogen. For root characteristics, elevated ozone concentrations significantly reduced the wheat root biomass, total root length and root surface area but increased the average root diameter.