为促进滨海区域粮食生产,以盐渍化麦田为研究对象,在测定土壤（0~20 cm）基本性质及小麦产量、生物量基础上,分析土壤肥力特征与小麦生产能力间的关系。结果表明,土壤含盐量与小麦产量、地上部生物量（生物量）呈极显著负相关（p〈0.01...为促进滨海区域粮食生产,以盐渍化麦田为研究对象,在测定土壤（0~20 cm）基本性质及小麦产量、生物量基础上,分析土壤肥力特征与小麦生产能力间的关系。结果表明,土壤含盐量与小麦产量、地上部生物量（生物量）呈极显著负相关（p〈0.01）,其关系符合三次函数方程。若以4 500 kg hm^-2作为最低目标产量,土壤含盐量应在3.1 g kg^-1以下。土壤有机质含量与土壤含盐量呈显著负相关（p〈0.05）,与小麦产量、生物量呈极显著正相关（p〈0.01）。土壤有机质含量增加能够降低盐渍化程度,促进小麦生产。将直接相连的下层（〉10~20 cm）与上（表）层（0~10 cm）土壤含盐量比值作为抑盐效率（E）,来评价有机质的抑盐作用,表层土壤有机质含量与E符合二次函数方程,有机质含量超过19.1 g kg^-1时,抑盐效果显著,可以作为土壤肥力培育目标值。此外,提高土壤速效钾含量对小麦生产也具有显著促进作用。研究结果对研究区域及相似地区进行土壤肥力培育和粮食生产具有重要意义。展开更多
Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB...Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB degradation were monitored. Reaction kinetic of these processes was also assessed. A rapid reaction took place for Fenton process at higher initial concentration of H2O2, higher temperatures, and more acidic conditions （pH 3）. Similarly, ozonation reaction exhibited rapid rates for higher ozone dose, higher temperatures, and more basic conditions （pH 11）. Complete NB degradation in 65 min was achieved using Fenton process. The conditions of complete elimination of 100 mg/L of initial NB concentration, were 250 mg/L of H202 concentration, pH 3, and 10 mg/L of Fe（Ⅱ） concentration. Under these conditions, 55% organic carbon elimination was achieved. Total organic carbon mineralization was attained in 240 rain reaction time by Fenton process with 900 mg/L of H202 concentration, and 30 mg/L of Fe（Ⅱ） concentration. Fenton reaction showed a pseudo-first order kinetic; the reaction rate constant was ranged from 0.0226 to 0.0658 min^-1. Complete NB degradation was also achieved for an ozone dose of the order of 2.5 g/L. The ozonation was studied at different ozone doses, different initial pH （7-11） and at different temperatures （15-35℃）. NB ozonation kinetic was represented by a bi-molecular kinetic model which was reduced to pseudo-first order kinetic. The pseudo-first order reaction rate constant was determined to increase at 20℃ from 0.004 to 0.020 min^-1 as the used ozone increased from 0.4 to 1.9 g/L.展开更多
文摘为促进滨海区域粮食生产,以盐渍化麦田为研究对象,在测定土壤（0~20 cm）基本性质及小麦产量、生物量基础上,分析土壤肥力特征与小麦生产能力间的关系。结果表明,土壤含盐量与小麦产量、地上部生物量（生物量）呈极显著负相关（p〈0.01）,其关系符合三次函数方程。若以4 500 kg hm^-2作为最低目标产量,土壤含盐量应在3.1 g kg^-1以下。土壤有机质含量与土壤含盐量呈显著负相关（p〈0.05）,与小麦产量、生物量呈极显著正相关（p〈0.01）。土壤有机质含量增加能够降低盐渍化程度,促进小麦生产。将直接相连的下层（〉10~20 cm）与上（表）层（0~10 cm）土壤含盐量比值作为抑盐效率（E）,来评价有机质的抑盐作用,表层土壤有机质含量与E符合二次函数方程,有机质含量超过19.1 g kg^-1时,抑盐效果显著,可以作为土壤肥力培育目标值。此外,提高土壤速效钾含量对小麦生产也具有显著促进作用。研究结果对研究区域及相似地区进行土壤肥力培育和粮食生产具有重要意义。
文摘Fenton and ozone treatment was investigated at laboratory scale for the degradation of aqueous solutions of nitrobenzene （NB）. Effects of reactants concentration （O3, H2O2, and Fe（Ⅱ））, temperature, and pH on NB degradation were monitored. Reaction kinetic of these processes was also assessed. A rapid reaction took place for Fenton process at higher initial concentration of H2O2, higher temperatures, and more acidic conditions （pH 3）. Similarly, ozonation reaction exhibited rapid rates for higher ozone dose, higher temperatures, and more basic conditions （pH 11）. Complete NB degradation in 65 min was achieved using Fenton process. The conditions of complete elimination of 100 mg/L of initial NB concentration, were 250 mg/L of H202 concentration, pH 3, and 10 mg/L of Fe（Ⅱ） concentration. Under these conditions, 55% organic carbon elimination was achieved. Total organic carbon mineralization was attained in 240 rain reaction time by Fenton process with 900 mg/L of H202 concentration, and 30 mg/L of Fe（Ⅱ） concentration. Fenton reaction showed a pseudo-first order kinetic; the reaction rate constant was ranged from 0.0226 to 0.0658 min^-1. Complete NB degradation was also achieved for an ozone dose of the order of 2.5 g/L. The ozonation was studied at different ozone doses, different initial pH （7-11） and at different temperatures （15-35℃）. NB ozonation kinetic was represented by a bi-molecular kinetic model which was reduced to pseudo-first order kinetic. The pseudo-first order reaction rate constant was determined to increase at 20℃ from 0.004 to 0.020 min^-1 as the used ozone increased from 0.4 to 1.9 g/L.
