共查询到19条相似文献，搜索用时 640 毫秒
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介绍了植树挖坑机的类型和设计要求,根据实践经验提出了各类植树挖坑机存在的问题.分析了3LY-500鱼鳞坑开沟犁的特点,针对该开沟犁存在的问题和不足,提出了优化设计方向,可为该开沟犁的整机结构改进及性能优化提供参考. 相似文献
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为防止山火蔓延、保护森林资源,在林区开设防火线是主要措施之一。但由于比较成熟的、专门用于开设防火线的开沟设备非常少,一般直接采用农用开沟设备进行作业,其开沟效率不高且杂草覆盖效果不好。基于多功能森林消防车,笔者设计了一款能与其相配套使用的三悬架型式的森林防火开沟犁,犁体曲面设计成三片曲率不同的曲面,以适应复杂土质环境,获得良好翻土性能。运用ANSYS软件对开沟犁的静力学、动力学及动力消耗进行了分析。结果表明,最大总体变形0.32 mm发生在犁铧刃口末端;最大应变0.000 2 mm、最大应力34.74 MPa发生在犁柱与犁片焊接最上端。犁体完全入土后土壤平均反力为7.89 k N;开沟犁整机所消耗的平均功率为23.67 k W。通过进行开沟犁的牵引阻力试验,获得单个犁体牵引阻力为6.9 k N,试验值与仿真值基本相符。 相似文献
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通过意大利瓦勒拉尼整地系统（由火车型犁和海豚型犁2种犁型构成,其中火车型犁近似水平沟式整地,海豚型犁近似大鱼鳞坑式整地）与常规开沟犁整地效益的对比试验,结果显示：同期覆土层（0～20 cm）的土壤含水量以瓦勒拉尼系统2种整地方式最高,是常规开沟犁整地的1.28倍和1.11倍。火车型犁整地的土壤容重为1.05 g/cm3,常规开沟犁整地为1.08 g/cm3,火车型犁整地后的土壤容重最小。瓦勒拉尼系统的火车型犁整地后的土壤毛管最大持水量是56.12%,远高于未整地的48.44%和普通犁整地的52.12%,分别是后两者的1.16倍和1.08倍。火车型犁整地后文冠果的地径达1.00 cm,是普通犁整地后地径0.42 cm的2.38倍;树高为0.93 m,是普通犁整地后树高0.53 m的1.75倍;保存率由59.30%提高至91.43%,提高了32.13个百分点;海豚型犁整地文冠果4年保存率则提高了13.42个百分点。 相似文献
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董长付 《林业机械与木工设备》1989,(3)
黑龙江省南岔营林机械厂在制造水湿地整地犁的基础上,又研制出单而翻土DM-开沟犁(见图)。这种开沟犁具有结构简单,使用方便的特点,改变了老式开沟犁双面翻土积水不能及时流入 相似文献
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赵义武 《林业机械与木工设备》1992,(2)
为保护农田防护林网,需在主副林带的两侧开出防护沟。以往,我们林场使用牵引式的开沟犁,作业时需两台拖拉机配合使用,机车的利用率低,生产成本高,开沟犁转移、升降很不方便。为此,我们经过认真分析研究,对牵引机具进行了改革,制造了一种新型的悬挂式开沟犁。这种悬挂式开沟犁是用一台红旗100推土机为动力,利用后 相似文献
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该项技术介绍的是以大犁开沟整地为基础 ,由良种壮苗、苗木保水、浸苗补水、扩坑保墒、适当深栽、分层踏实、培抗旱堆等 8个部分组成的系列抗旱造林方式。1 机械开沟整地1.1 机具采用JKL - 5 0型开沟犁 ,用链式拖拉机牵引。该犁开沟深度 4 5～5 0cm ,上口宽 110～ 12 0cm ,沟底宽2 6～ 80cm ,沟的断面积 0 .338m2 ,工作效率 3330m/h。1.2 适用范围适用于干旱、半干旱地区平缓沙地 ,也可用于 15°以下的黄土丘陵缓坡 ;还可用于开沟整地造林的中幼林抚育。2 选用良种壮苗定向培育良种壮苗 ,Ⅰ级苗使用率在 90 %以上 ,Ⅱ级苗使用率不高于… 相似文献
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根据铧式犁的结构特点,结合现代计算机辅助设计,研究并提出了一种基于Pro/E二次开发的犁体曲面计算机辅助设计方法.该方法以从现有犁体曲面采集的点数据为基础,利用Pro/E的逆向造型工具反求犁体曲面,并将其作为犁体曲面参数化模型,利用Pro/E提供的软件开发工具包开发出的一种犁体曲面三维参数化CAD系统.通过输入犁体曲面控制参数,该系统能够自动生成光顺性较好的犁体曲面的三维结构模型,有效缩短了产品的开发周期,降低了产品的设计成本. 相似文献
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铧式犁犁体曲面设计的现状与研究 总被引：5，自引：0，他引：5
通过对犁体曲面设计现状的分析，根据铧式犁特定的作业要求，结合现代设计方法的特点，研究并提出了一种用于犁体曲面设计的方法——Pro／E设计方法。该方法以部分解析法得出的参数为基础，利用Pro／E自身设计的强大功能，可以较好地表现犁体曲面的三维结构图，大大缩短了产品的开发周期，降低了产品的设计成本。 相似文献
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Sandrine Godefroid Dennis Monbaliu Wim Massant Beatrijs Van der Aa Bruno De Vos Vincent Quivy Nico Koedam 《Annals of Forest Science》2007,64(3):321-331
This paper describes the ground floor vegetation that developed four years after tillage implements in an ancient beech forest in central Belgium. The purpose of this study was twofold: (1) to explore whether tillage has a lasting effect on soil compaction and soil moisture as well as on vegetation characteristics; and (2) to analyse whether two distinct tillage treatments (rotary plough vs. disc plough), combined with vegetation control when necessary, have the same effect on soil compaction, soil moisture and plant establishment. Of the 29 species recorded, 15 showed a significant recovery after soil loosening in the studied forest area. Interestingly, different tillage treatments did not have the same influence on plant establishment. Treatment effects on soil structure and/or moisture status can be considered as causing the observed growth response. 相似文献
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本文结合作者对退耕还林工程管理的体会和MIS的实际开发经验 ,重点从管理信息系统目标和内容的确立、开发过程的组织与控制、退耕还林工程与MIS的最佳融合点等几个方面进行了分析 ,论述了MIS在退耕还林工程中的开发流程和方法。 相似文献
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鱼虽然作为园林中次要的动物造景要素，但它具有悠久历史、丰厚文化并促进了造园活动。以“鱼”元素景观为研究对象，通过梳理其在中国古典园林中的演变，将其表现形式划分为“以鱼生产”“以鱼成景”“以鱼装饰”“以鱼写意”四类，并总结了鱼元素景观启蒙、转折、深化、停滞 4 个发展时期的演变特征，进而探究不同时期造园理念的变化及造园理念与鱼元素景观之间互为促进的关系。从园林规划设计的角度对景观形式进行解析，探究不同形式背后所蕴含的造园理念，丰富鱼元素景观研究。 相似文献
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对宜昌市新增蔬菜基地的土壤肥力状况作了分析,结果表明：目前宜昌市新增蔬菜基地土壤酸碱度（pH值）较适宜蔬菜的生长,但有机质含量普遍低下,尤其以猇亭高家店村的土壤有机质含量最为缺乏;普遍缺磷,碱解氮含量大部分缺乏,速效钾含量不均等,并且差异极大,既有缺乏或极缺乏的土壤,又有富钾的土壤。提出了土壤的培肥措施：深耕翻地,打破水稻土的犁底层;增施有机肥,改善其通透性能;选择性种植作物,达到逐步培肥地力的目的;利用掺砂客土进行土壤改良,改善土壤的质地。 相似文献
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Tomás de Figueiredo Felícia Fonseca Afonso Martins 《European Journal of Forest Research》2012,131(6):1747-1760
Soil loss rates currently recorded in forests are very low. Nevertheless, that may not be the case during stand installation and early tree growth stage, when soil is disturbed and scarcely covered. Site preparation techniques, performed to improve soil conditions for plant growth, should help reducing this erosion potential. In this study, several site preparation techniques were applied prior to installing a mixed stand (Pseudotsuga mensiezii and Castanea sativa) and a subsequent monitoring scheme of run-off and soil loss ran for 2?years in order to compare their effectiveness for erosion control. The experimental area, near Macedo de Cavaleiros, NE Portugal, at 700?m elevation, with annual means of 656?mm rainfall and 12°C temperature, has Mediterranean climatic conditions. Experimental design comprised three blocks, corresponding to different topographical positions (near flat plateau, moderate slope shoulder and steep mid-slope), where eight treatments were randomly distributed in plots with 375?m2 area: (1) Original soil control (no intervention on the original abandoned field); (2) No subsoiling, no ploughing, plantation with hole digger; (3) Subsoiling over the whole area, with covering shovel; (4) No subsoiling, contour bunds shaped by two plough passes; (5) Subsoiling in future plantation rows, contour bunds shaped by two plough passes; (6) Subsoiling over the whole area, contour bunds shaped by two plough passes; (7) Subsoiling over the whole area, contour ploughing over the whole area; and (8) Potential erosion (subsoiling over the whole area, ploughing downhill). Sediment and water exported from small plots (2.5?m2 average area), two replicates per treatment and block, were collected after each rainfall erosion event, in a total of 21, summing 1,876-mm precipitation in 2?years. Mean annual run-off and soil loss in the original soil were 3.4?mm and 11.6?g?m?2, respectively. In treatments 2–7, values were higher 3–7 times, for run-off, and 5–12 times, for soil loss. Potential erosion averages 2.3 t ha?1 year?1. Soil loss and run-off tend to increase with tillage intensity associated with site preparation technique, even though average two-year losses, in all cases, are below tolerable rates. Soil loss and run-off rates decreased with time, becoming globally negligible after 2?years. Slight and moderate soil disturbance intensity site preparation techniques reduce erosion rates to 30% of potential erosion, halving the critical period when above tolerance rates may occur. 相似文献