Cross‐linked polyacrylates in post‐mining substrates: persistence and effects on plant growth

Application of hydrophilic polymers composed of cross‐linked polyacrylate can improve soil water‐holding capacity and accelerate the restoration of post‐mining substrates. In this work, we studied the persistence of a polyacrylate polymer incorporated into a soil and its impact on plant nutrients at a reclamation site of former lignite mining in Lusatia (Germany). In contrast to autumn application, the incorporation of the polymer enhanced the sequestration of plant‐derived carbon in the soil, which was reflected by a significant increase in the concentration of a lignin marker. Attenuated total reflexion–Fourier transform infrared spectra (ATR‐FTIR) and total elemental contents in the applied polymer suggested an intensive cation exchange between the polymer framework and the soil‐forming substrate. In addition, there was an enrichment of carbonaceous material, which seems to reduce the swelling and thus the water‐holding capacity of the cross‐linked polyacrylate. Conversely, this process protected the polymer structure from rapid decomposition.     

Nitrous oxide emission from a transplanted rice field in alluvial soil as influenced by management of nitrogen fertiliser

We investigated nitrous oxide (N₂O) emission from an irrigated rice field over two years to evaluate the management of nitrogenous fertiliser and its effect on reducing emissions. Four forms of nitrogenous fertilisers: NPK at the recommended application rate, starch–urea matrix (SUM) + PK, neem‐coated urea + PK and urea alone (urea without coating) were used. Gas samples were collected from the field at weekly intervals with the static chamber technique. N₂O emissions from different treatments ranged from 11.58 to 215.81 N₂O‐N μg/m²/h, and seasonal N₂O emissions from 2.83 to 3.89 kg N₂O‐N/ha. Compared with other fertilisers, N₂O emissions were greatest after the application of the conventional NPK fertiliser. Moreover, SUM + PK reduced total N₂O emissions by 22.33% (P < 0.05) compared with NPK during the rice‐growing period (P < 0.05). The results indicate a strong correlation between N₂O emissions and soil organic carbon, nitrate, ammonium, above‐ and below‐ground plant biomass and photosynthesis (P < 0.05). The application of SUM + PK in rice fields is suitable as a means of reducing N₂O emissions without affecting grain production.     

呼伦贝尔地区苜蓿人工草地CO_2通量变化特征

试验采用密闭箱技术对呼伦贝尔地区种植的苜蓿人工草地进行碳通量研究,采用反硝化-分解作用模型(DNDC)进行模拟。试验结果表明:对苜蓿人工草地CO2通量24h连续观测发现,CO2通量全天变化的平均值(238.15mg/(m2·h)与11∶00(245.32mg/(m2·h)的通量变化值接近,试验从早上9∶00~11∶00进行温室气体的采集方法合理、可行;在整个生长季变化表明,7、8月CO2通量变化较显著(P0.05),且受到降水的影响较大,伴随降水的发生,CO2通量会发生不同幅度的变化,土壤温度和含水量对CO2通量有一定的影响(r0.45,P0.05);通过DNDC模型的模拟,能较好的反映苜蓿人工草地CO2通量的变化情况,但模拟结果数值普遍有些偏高。     

Managing soil quality for humanity and the planet

Rather than a human-centric, the basic strategy of achieving Sustainable Development Goals must be focused on restoring and sustaining planetary processes. The urgency of meeting the demands of the humanity must be reconciled with the necessity of enhancing the environment. Increasing and restoring soil organic matter content of the degraded and depleted soils is critical to strengthening planetary processes.     

Effects of cover crop growth and decomposition on the distribution of aggregate size fractions and soil microbial carbon dynamics

Although the effects of cover crops (CC) on various soil parameters have been fully investigated, less is known about the impacts at different stages in CC cultivation. The objective of this study was to quantify the influence of CC cultivation stages and residue placement on aggregates and microbial carbon (C_mic). Additionally, the influence of residue location and crop species on CO₂ emissions and leached mineralized nitrogen (N_min) during the plant degradation period was also investigated. Within an incubation experiment, four CC species were sown in soil columns, with additional columns being kept plant‐free. After plant growth, the columns were frozen (as occurs in winter under field conditions) and then incubated with the plant material either incorporated or surface‐applied. With CC, concentrations of large and medium macroaggregates were twice that of the fallow, confirming positive effects of root growth. Freezing led to a decrease in these aggregate size classes. In the subsequent incubation, the large macroaggregates decreased far more in the samples with CC than in the fallow, leading to similar aggregate size distributions. No difference in C_mic concentration was found among the CC cultivation stages. CO₂ emissions were roughly equivalent to the carbon amounts added as plant residues. Comparison of columns with incorporated or surface‐applied residues indicated no consistent pattern of aggregate distribution, CO₂ emission or C_mic and N_min concentrations. Our results suggest that positive effects of CC cultivation are only short term and that a large amount of organic material in the soil could have a greater influence than CC cultivation.     

基质分散萃取-高效液相色谱法对菠菜中噻虫胺残留的检测

研究确立了乙腈为分散萃取溶剂,以羧基化双壁碳纳米管(DWCNTs-COOH)和石墨化碳黑(GCB)为基质分散材料的菠菜(Spinacia oleracea L.)样品中噻虫胺残留基质分散萃取前处理方法,建立并优化了乙腈等度洗脱的HPLC残留样品外标定量方法。结果表明,优化色谱条件下,噻虫胺标准样品的色谱保留时间为6.258 min,在0.05~100 mg/L范围内与对应色谱峰积分面积线性响应良好,回归方程为y=4.948 2x-1.316 9(R~2=0.999 7),噻虫胺在菠菜样品中0.1、0.5和5.0 mg/kg 3个水平的添加回收率均在85%以上,各添加水平的相对标准偏差均小于7%,该色谱条件下仪器检出限为0.052 7μg/L,方法的最低检测量为0.015 mg/kg。表明该残留样本前处理方法和样品检测方法简便、高效、经济、可靠,可满足噻虫胺在菠菜中的残留定量检测要求。     

椭圆嗜蓝层孔菌子实体化学成分研究

椭圆嗜蓝层孔菌(Phellinus ellipsoidea)子实体甲醇提取物依次用石油醚和乙酸乙酯萃取,其乙酸乙酯分部经柱层析分离得到11个化合物。经鉴定这11个化合物分别为:苯并(1,2-b,5,4-b′)二呋喃-3,5-二酮-8-甲酸甲酯(1)、原儿茶酸(2)、4-(3,4-二羟苯基)-3-丁烯-2-酮(3)、原儿茶醛(4)、Hispidin(5)、Hispolon(6)、Inoscavin A(7)、Phelligridin K(8)、Inoscavin C(9)、Inoscavin E(10)和Inonoblins B(11),其中化合物2、4、7、10为首次从该物种中分离得到。     

基于SVM的CFRW导电性建模预测研究

针对碳纤维增强木质复合材料（CFRW）导电性具有非线性的特点，采用基于支持向量回归机（SVM）的机器学习方法建立碳纤维增强木质复合材料导电性预测模型。结果表明，所建模型的预测精度高、泛化能力强.     

基于机载LiDAR数据的玉米叶面积指数反演

以机载LiDAR离散点云数据为数据源,基于植被冠层孔隙率与叶面积指数的关系,提出一种反演大田玉米叶面积指数的方法。对反演LAI和实测LAI进行对比分析,结果表明:基于Axelsson改进的不规则三角格网加密方法可以将地面点和非地面点分开,结合高分辨率影像能够提取出玉米冠层点云;基于孔隙率反演LAI,尼尔逊参数的选择对结果影响很大,利用扫描天顶角模拟尼尔逊参数,LAI反演结果接近于真实情况。利用机载LiDAR点云数据能精确地反演大田玉米LAI,该研究方法适用于中等高度的农作物,可以扩展到甜菜、甘蔗等其他中等高度农作物。     

低碳背景下县域经济发展方式转变的对策研究

加强节能减排,实现低碳发展,不仅是国家“十二五”规划纲要所提出的约束性目标,更是促进经济提质增效升级的必经途径.目前,我国县域经济仍以“高投入、高消耗、高排放”为主要特征,转变经济发展方式已成为县级政府所面临的迫切任务.为此,必须依据低碳发展理念和《2014 ～2015年节能减排低碳发展行动方案》的具体要求,培育有利于经济发展方式转变的要素基础和制度基础,加快推进产业结构的优化和升级,深化经济管理体制改革,不断进行制度创新,实施有利于科技进步的政策,完善环境管理制度,实现县域经济又好又快发展.