氮素形态对香榧苗期光合作用、主要元素吸收及氮代谢的影响

In this study,we measured the photosynthetic rate,the contents of primary inorganic elements,and nitrate reductase activity and leaf N content of Torreya grandis seedlings subjected to different inorga...     

麦草碱木质素三甲基季铵盐对酸性染料溶液的絮凝性能影响

以从造纸黑液中提取的麦草碱木质素为原料,通过曼尼希反应合成麦草碱木质素三甲基季铵盐,以脱色率为指标检测其对酸性黑ATT、酸性橙GG和酸性红B的絮凝性能。实验结果表明:对于0.1 g/l酸性黑ATT溶液,pH为2,麦草碱木质素三甲基季铵盐使用浓度在0～3 500 mg/l范围内时,脱色率随浓度增大而升高;麦草碱木质素三甲基季铵盐使用浓度为2 884 mg/l时,在pH为1～4范围内,脱色率随pH降低而增加。酸性橙GG和酸性红B也有类似的规律。由上述结论结合麦草碱木质素三甲基季铵盐和酸性染料的结构特点,认为絮凝过程先是麦草碱木质素三甲基季铵盐中的铵离子与酸性染料中的磺酸根之间氢键吸引,然后染料间产生"架桥"现象,具有三维网状结构的碱木质素分子继续网捕和卷扫脱除染料。     

氨固定对土壤微生物生物量氮矿化测定的影响

Two soils with relatively high(Soil 1)and low(Soil 2) ammonium fixation capacities were used in this study to examiune the effect of ammonium fixation on the determination of N mineralized from soil microbial biomass.Organism suspension was quantitatively introduced to Soil 1 at various rates.Both fumigation-incubation (FI) and fumigation-extraction (FE) methods were used to treat the soil.The amount of fixed NH4^ increased with increasing rate of organism-N addition.A close correlation was found between the amount of fixed ammonium and th rate of organism-m addition.The net increases of fixed NH4^ -N were equivalent to 38% and 12% of the added organism-N for FI and FE treatments,rspectively,in this specific soil.To provide isotopic evidence,^15N-labelled organism-N was added to Soils 1 and 2 at 121.4 mg N kg^-1.In FI treatment,22 and 3mg N kg^-1 of labelled N were found in the fraction of fixed NH4^ -N in Soile 1 and 2 respectively;while in FE treatment,9 mg N kg^-1 of labelled N was found in the fraction of fixed NH4^ -N in Soil 1 only.There was no labelled N in the fraction of fixed NH4^ -N in Soil 2.In all of the unfumigated (check) soils,there was little or no labelled N in the fixed fractions,probably because the organism-N added was easily mineralized and nitrified.A mean of 0.64 for KN value,the fraction of N mineralized in the killed microbial biomass,as obtained with inclusion of the net increase of fixed NH4^ -N,The corresponding value calculated with exclusion of the net increase of ficed NH4^ -N was 0.46 ,It was concluded that ammonium fixation was a problem in deterination of KN,particularly for soils with a high ammonium fixation capacity, Results also showed that microbial biomass N measurement by FFE method was less affected by ammonium process than that by FI method.     

聚乙二醇对五硼酸铵改性结构刨花板吸水性能的影响

试验引入聚乙二醇改性体系以补偿五硼酸铵处理结构刨花板时造成物理力学性能的降低,并研究了处理后结构刨花板的吸水性能。结果表明：24h吸水厚度膨胀率和24h吸水率这两项指标与五硼酸铵添加量的相关性最大,该两项结果均随五硼酸铵添加量的增加而增大。聚乙二醇种类对结构刨花板吸水性的影响大于添加量的作用。尤其是24h吸水率,4个添加量水平下的结果均无显著性差异。     

典型双季稻田基施碳酸氢铵和尿素的氨挥发损失研究

采用密闭室连续抽气法研究了湖南典型双季稻田,尿素和碳酸氢铵基施后的氨挥发特征。结果表明,基施碳酸氢铵(NC)稻田初始氨挥发强度和氨挥发总量大于基施尿素(UR)稻田。早稻季NC处理稻田氨挥发排放量为45.19 kg·hm-2,损失率达30.12%,UR处理氨挥发排放量为32.93 kg·hm-2,损失率达21.95%;晚稻季NC处理稻田氨挥发排放量为70.91 kg·hm-2,损失率达31.93%,UR处理氨挥发排放量为61.78 kg·hm-2,损失率达27.04%。基施尿素能够显著降低稻田氨挥发排放,减少氮素损失。     

调节安的微量比色分析方法

调节安(生物活性成分为 N,N-二甲基吗啉鎓氯化物)是一种高效、低毒、安全的新型植物生长延缓剂。本文介绍了该化合物微量比色分析方法。     

Fixed Ammonium Content and Maximum Capacity of Ammonium Fixation in Major Types of Tillage Soils in Hunan Province, China

In order to understand the status of fixed ammonium, fixed ammonium content, maximum capacity of ammonium fixation, and their influencing factors in major types of tillage soils of Hunan Province, China, were studied with sampling on fields, and laboratory incubation and determination. The main results are summarized as follows: (1) Content of fixed ammonium in the tested soils varies greatly with soil use pattern and the nature of parent material. For the paddy soils, it ranges from 135.4 ± 57.4 to 412.8 ± 32.4 mg kg⁻¹, with 304.7 ± 96.7 mg kg⁻¹ in average; while it ranges from 59.4 to 435.7 mg kg⁻¹, with 230.1 ± 89.2 mg kg⁻¹ in average for the upland soils. The soils developed from limnic material and slate had higher fixed ammonium content than the soils developed from granite. The percentage of fixed ammonium to total N in the upland soils is always higher than that in the paddy soils. It ranges from 6.1 ± 3.6% to 16.6 ± 4.6%, with 14.0% ± 5.1% in average for the paddy soils and it amounted to 5.8 ± 2.0% to 40.1 ± 17.8%, with 23.5 ± 14.2% in average for upland soils. (2) The maximum capacity of ammonium fixation has the same trend with the fixed ammonium content in the tested soils. For all the tested soils, the percentage of recently fixed ammonium to maximum capacity of ammonium fixation is always bellow 20% and it may be due to the fact that the soils have high fertility and high saturation of ammonium-fixing site. (3) The clay content and clay composition in the tested soils are the two important factors influencing their fixed ammonium content and maximum capacity of ammonium fixation. The results showed that hydrous mica is the main 2:1 type clay mineral in <0.02 mm clay of the paddy soils, and its content in 0.02–0.002 mm clay is much higher than that in <0.002 mm clay of the soils. The statistical analysis showed that both the fixed ammonium content and the maximum capacity of ammonium fixation of the paddy soils were positively correlated with the total 2:1 type clay mineral content and hydrous mica content in <0.02 mm clay and 0.02–0.002 mm clay at the significant level of P_0.01 or P_0.05, respectively, but not correlated with the total 2:1 type clay mineral content and hydrous mica content in <0.002 mm clay significantly. It demonstrated that the ammonium-fixing matrix of the tested soils mainly exists in the 0.02-0.002 mm clay. The above-mentioned results showed that fixed ammonium is a major form of N in the tillage soils in Hunan Province, China. It would play an important role in N nutrition of crops, especially for upland crops, and deserve to be further researched.     

氮肥对3种固氮蓝藻种群数量的影响

通过2种常用化肥对固氮鱼腥藻（Anabaena azotica Ley），球胞鱼腥藻（Anabaena sphaerica Born），多变鱼腥藻（Anabaena variabilio Kutzing）影响的研究。结果表明，尿素和碳酸氧铵在低浓度（20mg／L以下）表现为促进，当浓度为80mg／L时，则显著抑制其种群生长；且高浓度时，尿素和碳酸氢铵对3种藻产生较强影响，处理96h时的EC50值分别为54．0，67．0，85．7mg／L及73．7，63．1，92．2mg／L。     

凯氏全氮与固定态铵之间的关系

从中国各地采集了40种不同类型的土壤,以凯氏法、包括粘土矿物固定态铵的HF-凯氏法和凯氏法测定全氮后再用HF处理测定固定态铵的两步法分别测定了这些土壤全氮含量,并用Silva-Bremner法测定了其粘土矿物固定态铵含量,确定凯氏法测定的全氮是否包括固定态铵在内。结果表明,土壤全氮平均含量凯氏法测定的为1.622 gkg-1,HF-凯氏法为1.633 gkg-1,而两步法为1.656 gkg-1;两步法测定的全氮量明显高于凯氏法和HF-凯氏法。由此可见,凯氏法无法释放2∶1粘土矿物中的固定态铵,在2∶1型粘土矿物含量高的土壤上测定值也不是真正的全氮。供试土壤固定态铵含量平均为166 mgkg-1,占凯氏全氮10.1%;而用两步法测定的残余固定态铵含量平均为30.4 mgkg-1,占凯氏全氮的1.9%,固定态铵的18.3%。相关分析表明,固定态铵与残余固定态铵之间显著相关(r =0.598)。残余固定态铵高的土壤正是固定态铵含量高的土壤,而固定态铵含量高的土壤正是2∶1型粘土矿物含量高的土壤,因而凯氏法测定的全氮不能反映这些土壤全氮的真实情况。但对于2∶1型粘土矿物含量低的或无此类粘土矿物的土壤,凯氏法与其它方法的测定值无显著差异。     

双季铵盐型表面活性剂的吸附特性研究

以研究双季铵盐型表面活性剂BQAS吸附特性为目的,从溶液表面张力随浓度的变化、饱和吸附量等方面研究了双季铵盐BQAS的气液界面吸附特性;用双季铵盐BQAS和砂岩体系,在液固比一定时,从时间、浓度对静态吸附量的影响方面研究了双季铵盐BQAS的液固界面吸附特性。试验结果表明,双季铵盐BQAS能显著降低溶液表面张力,在溶液表面的饱和吸附量为1·58×10-6mol·m-2;在液固比为50∶1时,双季铵盐BQAS在砂岩表面(40~80目)的吸附最低平衡时间为90min,饱和吸附量为2·13×10-5mol·g-1,具有良好的表面活性。