作物残茬翻埋对土壤性质的影响

Chemical transformation, nutrient release and changes in the energy content of decomposing rape, sunflower and soybean residues confined in buried fiberglass bags were assessed in a laboratory study during a 340-day incubation period. The organic C decreased by about 70% while total N, after initial decay, remained almost constant for each type of residue. The NH₄⁺-N was progressively oxidized and, consequently, the NO₃^--N increased. The C/N ratio narrowed with loss of C. Hemicellulose, cellulose and lignin decreased with different trends for each crop residue. The energy content, was reduced to about 25% in rape, 30% in sunflower and 20% in soybean residues. Total P, K, Ca and Mg contents decreased for each type of residue. The results suggest that the three residues could improve the nutrient pool of the soil.     

玉米免耕破茬室内试验装置的研究设计

通过对国内外玉米免耕播种机破茬防堵部件的对比研究,确定采用滚动式破茬犁刀研制出本试验装置,并进行了室内土槽中的实验。该装置测量准确、方便,为研制出适合我国北方垄作玉米免耕破茬防堵部件提供了技术数据。     

农林废弃物超低酸水解装置及试验研究

自行设计了木质纤维素类生物质超低酸水解装置,该装置可以间歇进料方式实现生物质的超低酸水解。在该装置上分别以木聚糖和定量滤纸为模化物得到了半纤维素和纤维素水解的最佳工况,进而对白松、速生杨和玉米秸秆这三种在我国分布较为广泛的原料进行了超低酸两步水解研究,分别得到了51.24%、78.27%和84.10%的可水解原料转化率和48.19%、57.96%和37.48%总还原糖得率,并以GCMS定性还原糖外的其他产物,最后对水解残渣做了分析研究。     

自走式肉羊饲喂机的设计与试验

介绍了自走式肉羊饲喂机的主要结构组成及工作原理。为研究其工作性能,选取多浪羊为试验对象,采用饲喂机加工后的全混合日粮进行饲喂,以肉羊增重和饲料残留量为试验指标开展试验。试验结果表明:自走式肉羊饲喂机加工的全混合日粮变异系数为8.9%,混合均匀度为91.1%,饲料搅拌混合均匀,满足肉羊饲料食用要求;对于肉羊养殖,采用全混合日粮自由采食饲养方式较人工分饲方式增重效果极显著(P0.01);饲料残留量减少极显著(P0.01)。本自走式肉羊饲喂机的研制满足了肉羊饲喂的要求,可以提高经济效益。     

气相色谱—串联质谱法同时测定洋葱中29种农药残留

为提高检测洋葱中农药残留的准确性,探讨用GC-MS/MS检验29种农药的方法。试验结果表明:GC-MS/MS法可同时测定洋葱中的29种农药残留,在0.001～0.500mg/L质量浓度范围内,线性关系良好,相关系数为0.9870～0.9987,相对标准偏差小于8.3%;加标回收率为79.6%～102.1%;检出限为0.01～1.42μg/kg。     

Agricultural residues in panel production – Impact of silica particle content and morphology on tool wear

Abstract

Considering ongoing global deforestation and the increased demand for raw materials in all wood-processing sectors it is necessary to seek and employ alternative resources. Agricultural residues are potential sources of alternative lignocellulose-based raw materials. Research on substitute materials for wood panel production mainly focused on physical and mechanical properties of boards while much remains to be learned about machining. Therefore, studies were carried out to analyse the relationship between ash and silica content and their impact on tool wear. Ash and silica contents of agricultural residues were determined following ISO 3340. Particle morphology and elemental composition of selected materials were analysed using scanning electron microscopy and energy-dispersive X-ray analysis. Tool wear tests were carried out using particleboards made from wheat straw, canola straw and spruce. Analyses of various plant materials displayed no correlation between ash and silica content. Bio-mineralised silica structures in wheat and canola were different compared to coarse silica found in wood-based particleboard. Tool wear caused by these agricultural residues was just moderately increased compared to wood, despite the fact that their silica contents were many times higher. Furthermore, the impact of abrasive substances on wear behaviour was influenced by the density of the panels.     

Analysis of sawn lumber production from logging residues of branchwood of <Emphasis Type="Italic">Aningeria robusta</Emphasis> and <Emphasis Type="Italic">Terminalia ivorensis</Emphasis>

One way of meeting the supply demands of the wood industry is through the reduction of waste in timber processing. It has been estimated in Ghana that for every tree felled, nearly 50% of the tree volume is left in the forest in the form of branches, crownwood, and stumps. In this study, the potential of utilizing branchwood as raw material from logging residues to help meet the timber demands of the downstream processing sector was analyzed experimentally. The sawing characteristics of the branchwood of Aningeria robusta and Terminalia ivorensis with diameters in the range 10–25 cm using live sawing and cant sawing methods were determined using a randomized complete block design, 2 × 4 factorial with three replications. Experimental results indicate that, the relative lumber value yields for first and second grade boards of A. robusta and T. ivorensis branches were 25 and 20%, respectively, while the green lumber volume yields were 40 and 32%, respectively. A high proportion of sapwood and the occurrence of washboarding in T. ivorensis contributed to that species’ relatively low lumber value and volume yield. The experimental results further indicate that the sawing technique used had no significant influence on lumber yields. However, at 5% level of significance, significant differences in lumber yield existed between some of the diameter classes.     

沥青老化再生的实验路径研究

沥青路面是现阶段应用最广泛的路面形式,随着使用年限的增长路面上沥青材料发生老化后使得沥青路面的路用性能降低,这样沥青路面的再生技术应运而生.通过对比不同老化方法和不同的老化时间得到的沥青残留物的各种指标与实际的废旧沥青的各种指标,找到方便准确的适用于实验研究的老化方法,然后通过对比不同的再生方法,寻找到用于实验室研究的沥青再生方法,从而找到适用于实验研究的老化再生路径.     

利用木质剩余物与废纸制备纸浆模塑材料的比较

对三种缓冲材料及利用木质剩余物一次纤维和废纸再生纤维制备纸浆模塑材料工艺过程进行对比。并利用扫描电镜观察热压干燥和真空干燥成型时,木质剩余物一次纤维与废纸再生纤维纤维形态结构的变化。结果表明：木质剩余物一次纤维纤维长度、宽度较废纸再生纤维得均匀,废纸再生纤维纤维表面有所损伤,纤维间的空隙增加,会导致与纤维间结合力有关的抗张强度、耐破强度和耐折强度等物理性能地下降。在生产实践中,要根据包装物的具体情况,选择合适的纸浆模塑原材料。     

Possibilities for energy wood procurement in north-west Russia: Assessment of energy wood resources in the Leningrad region

Abstract

Methodology to assess the potential for energy wood procurement in Russia is described in this article and applied to the Leningrad region. Wood from thinnings, logging residues, non-industrial roundwood and residues from sawmilling are considered as sources for energy production. Energy wood available in the region, based on the 2004 actual cut, is approximately 4 million m³. Nearly 86% of this is non-industrial roundwood and felling residues, and 14% is by-products from sawmilling. Almost two-thirds of the non-industrial roundwood and felling residues are in cutting areas and one-third is in central processing yards. Deciduous tree species (birch and aspen) dominate in energy wood, representing about 65% of the total amount of felling residues and non-industrial wood. It is possible to intensify utilization of forest resources and thereby also to increase the use of wood in energy production. The total amount could be 54% higher if the allowable cut was fully utilized and 124% higher if thinnings were also utilized completely. There are, however, significant intraregional differences, as the current rate of utilization of forest resources varies in the region.