再生稻收割机刚柔耦合杆齿脱粒装置的设计与试验   总被引：1，自引：0，他引：1  

曾山  曾力  刘伟健  魏斯龙  涂清柳  陈海波 《华南农业大学学报》2022,43(5):61-69

目的 针对再生稻头季收获时籽粒和秸秆含水率较高,籽粒与稻穗的黏结力较大,采用传统刚性杆齿脱粒装置的收割机收获时会导致大量籽粒破碎的问题,在轴流式脱粒滚筒的基础上设计了一种刚柔耦合杆齿的脱粒滚筒。方法 采用EDEM仿真软件对脱粒过程进行仿真模拟,通过后处理获得3种不同杆齿(刚性、柔性、刚柔耦合)对籽粒的平均法向打击力和切向揉搓力;以夹带损失率、破碎率和未脱净率为评价指标,分别以不同滚筒转速下的单因素和以滚筒转速、水稻籽粒含水率、杆齿种类为因素的三因素三水平进行不同杆齿的正交台架验证试验。结果 EDEM仿真结果表明,在滚筒转速分别为650、750和850 r/min时,3种杆齿对籽粒的平均法向打击力和切向揉搓力均表现为刚性杆齿最大、柔性杆齿最小。单因素试验结果表明,刚性杆齿脱粒装置的籽粒破碎率明显高于柔性杆齿脱粒装置和刚柔耦合脱粒装置,在滚筒转速为900 r/min时,柔性杆齿、刚性杆齿和刚柔耦合杆齿的破碎率均很高,分别为1.632%、1.925%和2.564%;柔性杆齿脱粒装置的未脱净率和夹带损失率明显高于刚性杆齿脱粒装置和刚柔耦合脱粒装置,在滚筒转速为900 r/min时,柔性杆齿、刚性杆齿和刚柔耦合杆齿的未脱净率均很低,分别为0.286%、0.071%和0.240%,在滚筒转速为850 r/min时,柔性杆齿、刚性杆齿和刚柔耦合杆齿的夹带损失率均很低,分别为1.595%、0.729%和1.341%。正交试验结果表明,影响籽粒夹带损失率和破碎率的因素顺序依次为杆齿种类 > 滚筒转速 > 籽粒含水率,影响未脱净率因素的顺序依次为杆齿种类 > 籽粒含水率 > 滚筒转速。结论 相同条件下,刚柔耦合脱粒装置能够在保证籽粒脱净率的前提下,降低籽粒破碎率。研究结果可为再生稻收割机脱粒装置的设计与田间应用提供参考。  相似文献   

4SHY-2小型不对行玉米联合收获机的研究   总被引：1，自引：0，他引：1  

赵树智 《山西农业大学学报(自然科学版)》2005,25(3):270-271,288

为了缓解玉米收获机械研究发展缓慢,赶不上生产发展的需要,在广泛调研的基础上,根据玉米生产农艺情况,研制了小型不对行玉米联合收获机。结果表明该机可在一次完成两行玉米收获的同时进行秸杆还田等作业,为农民提供了一种省工、省力、经济有效的机具。  相似文献   

Microbial communities of the ant Formica exsecta and its nest material     

Stafva Lindström  Sari S. Timonen  Liselotte Sundström 《European Journal of Soil Science》2023,74(3):e13364

In this study, we investigated the bacterial and fungal microbiomes of the ant Formica exsecta (Hymenoptera, Formicidae), and assessed whether the microbial communities inside the ants differ from those in their nest material. Furthermore, we investigated whether the microbial communities inside the ants are conserved across time. To achieve this, we sequenced the bacterial 16S rRNA, and the fungal ITS region in entire adult worker ants and their nest material by Illumina MiSeq. We found that both the bacterial, and the fungal microbiomes form communities discrete from those in the surrounding nest material. In addition to the differences in species composition, we also found that bacterial species diversity, species richness, ζ diversity, and evenness were lower in ants than in the nest material. For fungi, only species richness was lower in the ants than in the nest material. The rate of within-colony species turnover across sampling events was not statistically significant for bacteria, but highly significant for fungi. This suggests that the fungal communities in the ants are less stable than the bacterial ones. Four bacterial taxa (Alphaproteobacteria, Proteobacteria, Staphylococcus, and Streptococcus), and two fungal taxa (Davidiella and Cryptococcus) formed a core microbiome, being consistently present and more abundant in the ants, but absent in the nest material. In all other cases differences in community composition and structure were due to taxa that were more consistently present and more abundant in the nest material, and frequently absent in the ants. Furthermore, we found 36 unique OTUs identified as Proteobacteria, and 82 unique OTUs identified as Alphaproteobacteria in the ants, representing 2.5% and 5.8% of all bacterial OTUs and 24.6% and 41% of the total number of bacterial sequences. This suggests that F. exsecta harbours a considerable bacterial diversity that so far remains unexplored.  相似文献   

Contribution of red wood ant mounds to forest floor CO₂ efflux in boreal coniferous forests     

T. Domisch  L. Finér  A.C. Risch  P. Niemelä 《Soil biology & biochemistry》2006,38(8):2425-2433

Red wood ants (Formica rufa group) are important elements in boreal forest ecosystems, where they occur in high abundance and build large and long-lasting, above-ground mounds of organic material. However, little is known on their role in the carbon (C) cycling in boreal forests. We measured temperature and carbon dioxide (CO₂) efflux from three different-sized wood ant mounds and the surrounding forest floor from May 2004 to April 2005 in Norway spruce [Picea abies (L.) Karst.] dominated forests in eastern Finland. Additionally, mound and forest floor temperatures were measured continuously and CO₂ effluxes at 2-4-week-intervals. During the ants’ active season (May-September), measurements were conducted in the morning, afternoon, evening and at night, while fluxes were measured once a day during the ants’ inactive season. CO₂ emissions from the mounds were up to nearly eight times higher than those from the surrounding forest floor during the active season of the ants, but no statistically significant differences were observed during the period from October to February. Both mound and forest floor CO₂ fluxes were highly correlated to mound or forest floor temperature. Based on our measurements, we are able to estimate the annual CO₂ efflux from ant mounds and the surrounding forest floor, based on nonlinear regression analyses using CO₂ flux as dependant and mound or forest floor temperatures as independent variables. Although red wood ant mounds were found to be “hot spots” for CO₂ efflux, that increase the spatial heterogeneity of C emissions within a forest ecosystem, their annual emissions were only 0.30% of that from the forest floor. Thus, our results indicate that red wood ant mounds do not directly contribute significantly to the overall C budget of the boreal forest ecosystem studied.  相似文献   

大头蚁 Pheidole indica Mayr.与环境温度的关系     

郭亨孝 《西南大学学报(自然科学版)》1988,(1)

大头蚁 Pheidole indica Mayr.卵、预蛹、蛹的最适温度是24℃。20～24℃是蛹的发育恒定温度。成虫不能忍耐5℃以下低温,5～-5℃为亚致死低温,-5～-15℃为致死低温;成虫能忍耐35℃高温,40～50℃为亚致死高温。  相似文献   

Urban ants of the city of Buenos Aires,Argentina: species survey and practical control     

Roxana Josens  Francisco Sola  Jimena Lois-Milevicich  William Mackay 《国际虫害防治杂志》2017,63(3):213-223

ABSTRACT

Ants are among the most diverse, abundant and ecologically significant organisms on earth. They have colonized almost all existing habitats, including urban areas, where they may pose serious problems for human activities. Here, we present different aspects of our studies on urban ants in the city of Buenos Aires aimed at collecting information on the species present in the city and at improving bait control strategies via laboratory assays. The use of these baits represents a control strategy that is environment-friendly as it avoids indiscriminate pesticide release. Moreover, we show that our baits exhibit higher efficiency when compared to a commercial bait, as it is optimized in terms of the ants’ feeding behavior even when both have the same active compound and at the same concentration. This work represents the first integrative study on urban ants in the city of Buenos Aires and indicates that the control of invasive species in urban settings may be improved by increasing the scientific knowledge of the biology of the target species.  相似文献   

Single-tree and Group Selection in Montane Norway Spruce Stands: Factors Influencing Operational Efficiency     

《Scandinavian Journal of Forest Research》2012,27(1):79-87

The operational efficiency of single-tree and group selection with a single-grip harvester was studied in uneven-aged spruce forests at high altitudes in southern Norway. Three harvest intensities of single-tree selection and two group sizes were examined in group selection. Single-tree selection included harvest intensities of 25, 45 and 65% of basal area. Group sizes for group selection were 0.063 and 0.250 ha. Normally, single-tree selection is considered less efficient than group selection or clear-cutting. In this study, because time consumption per cubic metre was primarily dependent upon average harvested tree volume, the large harvested tree size for single-tree selection allowed this treatment to be more efficient than group selection. The two blocks in this study were part of a larger design of five blocks with identical treatments under varying stand conditions. The relative operational efficiency of single-tree selection compared with group selection was greatest in stands of low stocking. Other studies have also shown that mechanical damage to the residual stand is lowest under these conditions.  相似文献   

An oral bioassay for the toxicity of hydramethylnon to individual workers and queens of Argentine ants,Linepithema humile     

Linda M Hooper‐Bi  Michael K Rust 《Pest management science》2001,57(11):1011-1016

We have developed an oral bioassay to determine the toxicity of hydramethylnon to individual workers and queens of the Argentine ant, Linepithema humile. We fed seven concentrations of hydramethylnon in suspension to individual workers or queens, determined the amount of hydramethylnon ingested and evaluated the individual ants for mortality 14 days later. At concentrations ≥0.37 g liter^?1, the amount of liquid the queens ingested decreased dramatically, indicating that Argentine ant queens may detect hydramethylnon. Significantly larger volumes of the two highest concentrations of the hydramethylnon suspension were ingested by the workers, compared to the lower concentrations, suggesting that hydramethylnon may act as a feeding stimulant for the workers. Worker mortality was higher than queen mortality at the highest concentrations tested. The highest worker mortality resulted when the ants ingested 1.03 µg of hydramethylnon per mg of ant tissue. At the highest concentration (1.0 g liter^?1) tested, workers ingested almost 12 times as much active ingredient per mg of body weight as did queens, suggesting that, in order to increase mortality of queens, multiple feedings must occur. © 2001 Society of Chemical Industry  相似文献   

热带雨林林冠层和林下层生物捕食水平的调查     

权园园  邓丽芳 《绿色科技》2019,(8):26-27,30

指出了热带雨林作为地球上生物多样性最为丰富的生态系统,有着复杂的物理结构和生物交互。林冠层和林下层由于接受光照等条件不同,造成了不同的微环境。在不同的微环境里,蚂蚁和鸟类等捕食者对植食性昆虫的捕食水平可能有所差异。利用绿色橡皮泥制作模拟自然状态下的毛毛虫,探究了其在热带雨林林冠和林下层的被捕食的水平的差异。结果显示:林下层的捕食水平显著高于林冠层,并且蚂蚁有着显著高于鸟类的捕食水平。这说明热带雨林的林冠层资源丰富、结构复杂,在为植食性昆虫提供大量食物资源的同时也能为其提供庇护从而躲避天敌,尤其是鸟类的捕食。  相似文献   

哀牢山西坡垂直带土壤蚂蚁群落多样性     

陈友  罗长维  李宏伟  徐正会 《河南农业科学》2011,40(2):81-85

采用样地调查法,对哀牢山西坡4个垂直地带8种植被类型的土壤蚂蚁群落多样性进行调查。结果如下:共有74种土壤蚂蚁,其中42种为优势种;土壤蚂蚁群落多样性随海拔高度增加呈规律性的变化:优势种所占比例逐渐递增,优势种数目降低、物种数目递减、物种多样性指数降低;在8种植被类型中,土壤蚂蚁个体密度、优势种数量、物种数目、物种多样性指数、均匀度指数在思茅松林、针阔叶混交林和季风常绿阔叶林3种植被类型中较高,而在干性常绿阔叶林、半湿润常绿阔叶林、常绿阔叶苔藓矮林、河谷稀树灌木草丛和中山湿性常绿阔叶林4种植被类型中较低。  相似文献