竹原纤维和竹粉纤维形态和化学成分分析

以3年生毛竹材为原料,研究了毛竹竹粉和竹原纤维的纤维形态和化学成分。纤维形态分析结果表明:竹原纤维的宽度(143μm)与竹粉(136μm)相当,长度(22.63 mm)远高于竹粉(0.61 mm),使其长宽比(158.25)远高于竹粉(4.49)。化学成分分析表明:竹原纤维的纤维素含量(65.6%)比竹粉(37.3%)高得多,聚戊糖含量(17.1%)略低于竹粉(20.1%)。竹粉中的木质素含量为24.5%,是竹原纤维中木质素含量(11.5%)的2倍多。竹原纤维的高纤维素含量和低木质素含量是其广泛应用于制浆造纸行业的重要原因。     

红火蚁信息素及其在化学防治中的应用研究进展

文章介绍了红火蚁的危害特征,分析了目前国内外红火蚁防治的主要方法,对利用化学信息素类物质防治红火蚁的研究方法及进展进行了综述;通过借鉴化学信息素在其他害虫防治中的应用,重点分析了化学信息素在红火蚁防治中的必要性和可能性,对红火蚁相关信息素的特点和化学结构进行了详细描述,并介绍了相关化学信息素的合成方法,揭示了信息素类物质在红火蚁综合防治中的重要性及优越性。     

辽东山地冰缘地貌上覆土壤粒度及元素地球化学

对辽东山地典型冰缘地貌上覆土壤的粒度、常微量化学元素进行测试分析,结果表明:土壤颗粒组成包括黏粒20.79%、粉粒69.54%和砂粒9.67%,平均粒径整体偏细,约为6.45Ф,不同土壤类型、地貌类型及坡向的粒度分布存在一定差异。土壤元素化学组成以SiO₂（45.60%）,Al₂ O₃（12.90%）,Fe₂O₃（3.90%）,K₂O （2.17%）为主,最大比例可达73.36%。元素Ca,Na,P,Sr显著淋溶,而Mn,Ti,Cu,Zn则相对富集,其他元素迁移不甚明显。少数元素还表现出与粒度分布存在显著关联,其中K,Na,Sr,Ba多存在于砂质土壤中,而元素Ti则容易在粒度更细致的黏土颗粒中留存。化学风化指数CIA均值约为65.50,Rb/Sr约为0.70,反映风化程度较低,且长期经历干冷气候,A—CN—K三角模型表明,研究区土壤风化以脱钙钠、富铝为主,风化水平尚处于低等风化阶段中后期。     

Classification of herbicides according to chemical family for weed resistance management strategies – an update

There are inaccuracies in the chemical families of the WSSA and HRAC herbicide classification systems which could limit their practical use in herbicide‐based weed management strategies. In essence, these inaccuracies could be divided into four parts: (i) the nomenclature of many of the chemical families is not correct, (ii) distinct active ingredients are grouped in same chemical families, (iii) many chemical families have been repeated in at least two modes of action/herbicide groups, and (iv) many active ingredients have not been assigned to chemical family, herbicide group or mode of action. The aim of this study was to revise the current classifications and to propose corrections for the current ones. Detailed investigations on chemical structure of the active ingredients of the registered herbicides showed that some moieties have the same mechanisms of action. According to this study, these moieties have been assigned to the names of chemical families and active ingredients are then classified within the chemical families accordingly. This study has 119 chemical families, compared with 145 in the WSSA system and 58 in the HRAC system. A major priority of this study is the number of active ingredients covered; we included 410 active ingredients with known mechanisms of action and herbicide groups, more than 100 active ingredients more than the current classification systems. Overall, this study provides better opportunities for the management of resistance to herbicides through the application of improved pure and applied knowledge.     

围栏与不同放牧强度对东祁连山高寒草甸植被和土壤的影响

在东祁连山高寒草地,对围栏7年和不同放牧强度的草地进行了物种数、地上生物量、地下生物量、土壤理化性质等研究。结果表明,围栏7年的高寒草地鲜草产量为425.8 g·m-2,显著高于夏季中牧159.3 g·m-2和夏季重牧91.0 g·m-2,但与冬季轻牧、夏季轻牧差异不显著。围栏条件下的物种数为26.3种·16 m-2,显著低于其他放牧条件下的物种数,但显著高于夏季重牧条件下的物种数23.0种·16 m-2;轻度或重度放牧都会使物种数减少,夏季中牧下的物种数最高(33.5种·16 m-2)。在0~10 cm的表层土壤中,围栏7年的草地根系生物量显著高于其他放牧强度。随着放牧强度的增加,根系生物量在0~10 cm土壤中呈下降趋势,在30~40 cm土壤中则表现为升高趋势。围栏7年的土壤容重低于其他放牧强度下的土壤容重,但差异不显著;夏季重牧的土壤容重显著高于围栏7年和其他放牧强度的土壤容重。随着放牧强度的增加,0~10 cm土壤碱解氮增加,围栏7年草地最低。围栏封育可有效改善和恢复草地植被,但不能长时间禁牧不进行放牧利用。合理的放牧能够维护高寒草甸草地生态系统功能、促进物种丰富度和土壤营养的均衡。     

Seasonal dynamics of bioenergy characteristics in grassland functional groups

Semi‐natural grasslands (SNG) are considered as bioenergy resources, either for combustion or for biogas production. To provide information on the seasonal (June–August) dynamics of herbage quantity and chemical composition, we studied the effects of factors on the proportions of four plant functional groups, chemical composition and total biomass yield at twelve sites representing three Estonian SNG types. Biomass yield increased only in alluvial meadows with the largest contribution of sedges/rushes (39%). Grasses dominated in dry‐to‐mesic meadows (62%) and other forbs in wooded meadows (55%). Concentration of fibre was highest in grasses and sedges/rushes (682 and 645 g NDF kg^?1), and lignin was highest in legumes and other forbs (103 and 113 g kg^?1). Legumes contained more C and N (447 and 25 g kg^?1) and grasses more Cl (1 g kg^?1). The highest concentrations of Mg, K and ash were in other forbs (4, 18 and 80 g kg^?1), and Ca in legumes (16 g kg^?1). The results are discussed in the context of suitability of different functional groups and SNG types for bioenergy conversion. Grasses and sedge‐/rush‐rich biomass are considered suitable for methane production. Biomass harvesting in July and minimizing the problems with N and Cl during combustion need to be considered. Forb‐rich biomass should be pre‐treated before direct combustion.     

青藏高原高寒湿地不同季节土壤理化性质对放牧模式的响应

本文分析了青藏高原东缘高寒湿地在全年放牧、冬季放牧和全年禁牧3种放牧模式下土壤理化性质的变化,探讨其在不同土层深度的变化及季节性动态。结果如下:1)沿着全年禁牧—冬季放牧—全年放牧3种放牧模式,土壤表层(0~15 cm)及下层(15~30 cm)的土壤含水量和有机碳含量显著减小。2)土壤含水量、有机碳、全氮、全磷和速效氮含量均随土层深度的增加而降低,而速效磷表现为无规律。3)3种放牧模式下表层土壤有机碳含量均为:9月>5月>7月;全氮和全磷含量一般都在9月份较高,而速效氮和速效磷含量9月份最低,每种放牧模式下它们之间的具体差异也不完全相同。4)除5月份,两个土层土壤全氮含量均与有机碳含量呈极显著正相关。综上,全年放牧模式加快了土壤中C、N、P的周转,使土壤养分输出量增加,进而导致土壤肥力下降,草地退化。     

不同类型白刺沙丘土壤理化性状与微生物相关性研究

利用民勤荒漠绿洲过渡带不同类型白刺沙丘的土壤微生物、土壤理化性状及二者之间的相关性进行研究,旨在探讨白刺沙丘的成土过程,为绿洲生态建设提供基础数据,结果表明,1)固定、半固定和流动沙丘粘粒、粉粒、细砂粒、粗砂粒含量差异较大;土壤养分含量与土壤粘粒、粉粒、细砂粒等细沙物质含量呈正相关性,与粗砂粒含量呈负相关性,表现为土壤养分含量随土壤颗粒的增大,相关性减弱。2)土壤微生物类群数量在半固定沙丘明显高于固定沙丘和流动沙丘。3)过渡带土壤均处于偏碱性状态,有机质、全氮、全磷、全钾、水解氮、速效钾、速效磷和CaCO₃含量随沙丘发育年代的增加逐渐增加。4)不同年代沙丘中土壤微生物和土壤理化因子均具较好的相关性,尤其是细菌和放线菌与pH值呈显著的负相关关系,土壤有机质含量与三大菌群数量都表现出显著的正相关关系。     

KOH活化法制备沙柳枝木活性炭的研究

活性炭是一种疏松多孔的碳单质,具有吸附作用,已在诸多领域广泛应用,例如,食品加工、军事化学防护、环境保护等。针对沙柳枝木的利用现状,选取KOH为活化剂并且采用微波法制备沙柳枝木活性炭,研究了活化剂辐射时间、质量浓度、液料比、辐射功率、浸渍时间等因素对活性炭吸附性能的影响,通过对单因素试验结果的正交优化,得出活性炭制备的最佳方法如下：KOH活化法制备沙柳枝木活性炭的最佳工艺条件为：液料比4:1、浸渍时间18 h、辐照功率560 W、辐照时间20 min,该工艺条件下所制备的活性炭成品碘吸附值为1011.01 mg/g,达到了GB/T 13803.2—1999中一级品标准。     

龙竹秆材化学成分分析

龙竹是具有较高开发利用价值的大型丛生竹种。通过对龙竹秆材化学成分分析测定,可以考察其作为制浆造纸原料的可行性。结果表明,龙竹秆材综纤维素含量高,木质素含量相对较低,可满足纸浆工业对原料的基本要求,属于优良的制浆造纸原料,值得在气候适宜的地区推广种植。由于龙竹秆材灰分含量和苯醇抽出物含量较高,且在各部位间分布差异较大,在以龙竹为原料生产化学浆时,应该尽量将不同部位的竹材分开处理,并适当增加蒸煮时化学药品的用量或适当延长蒸煮时间。