人人文库网 > 图纸下载 > 毕业设计 > 1WX-90型植树挖穴机设计【田间拖拉式植树挖坑机】【全套CAD图纸和毕业答辩论文】

fulltext.pdf

1WX-90型植树挖穴机设计【田间拖拉式植树挖坑机】【全套CAD图纸和毕业答辩论文】

资源目录

1WX-90型植树挖穴机设计【田间拖拉式植树挖坑机】【全套CAD图纸和毕业答辩论文】.rar

中文文献

范数最优控制理论在植树挖坑机钻头主轴纵向振动系统中的应用.pdf---(点击预览)

植树挖坑机钻头纵向振动系统动力学模型建立与求解.pdf---(点击预览)

植树挖坑机钻头扭转振动数学建模与仿真.pdf---(点击预览)

植树挖坑机的设计.pdf---(点击预览)

植树挖坑机坑形控制与挖坑阻力计算方法研究.pdf---(点击预览)

挖坑机刀片切削模型的建立及其MATLAB分析.pdf---(点击预览)

基于ANSYS的植树挖坑机主轴的优化设计.pdf---(点击预览)

受扭钢丝软轴的强度及刚度计算.pdf---(点击预览)

便携式挖穴机的研究设计.pdf---(点击预览)

一类挖坑机械钻头横向振动系统的最优控制问题.pdf---(点击预览)

1W50_30_型植树挖坑机的研制与应用.pdf---(点击预览)

外文翻译

外文翻译.doc---(点击预览)

fulltext.pdf---(点击预览)

A1箱体.dwg

A4固定轴.dwg

A4固定轴板.dwg

A4大端盖.dwg

A4隔套Ⅰ.dwg

A4隔套Ⅱ.dwg

上端盖.dwg

加强板.dwg

加强肋.dwg

加强角板.dwg

大端轴承座（A4）.dwg

大齿轮（A3）.dwg

封板（A4）.dwg

小端盖（A4).dwg

总装图（A0）.dwg

拉板1.dwg

支撑杆.dwg

支臂.dwg

田间作业状态图(A2).dwg

田间工作作业图(A2).dwg

立板.dwg

立柱.dwg

立轴（A3).dwg

轴承座（A3).dwg

轴承端盖焊合（A3）.dwg

连接花键.dwg

钻头焊合（A3).dwg

齿轮箱（A1).dwg

齿轮轴（A3).dwg

压缩包内文档预览：

编号：10452471 类型：共享资源大小：5.14MB 格式：RAR 上传时间：2018-08-15 上传人：好资料QQ****51605 IP属地：江苏

50
积分

版权申诉 word格式文档无特别注明外均可编辑修改；预览文档经过压缩，下载后原文更清晰！ 立即下载

关键词：: 1WX-90型植树挖穴机设计【田间拖拉式植树挖坑机】【全套CAD图纸和毕业答辩论文】 wx 90 植树挖穴机设计田间拖拉疲塌挖坑全套 cad 图纸以及毕业答辩论文

资源描述：

【温馨提示】购买原稿文件请充值后自助下载。

以下预览截图到的都有源文件,图纸是CAD，文档是WORD，下载后即可获得。

预览截图请勿抄袭，原稿文件完整清晰，无水印，可编辑。

有疑问可以咨询QQ：414951605或1304139763

1WX-90型植树挖穴机设计

摘要：现代新型挖坑机的研发主要向系列化、多功能和高性能方向发展。本植树挖坑机是针对目前使用广泛的江苏50型四轮拖拉机配套而设计的。悬挂式挖坑机采用与拖拉机三点悬挂式联接，即钻头在悬挂支臂的一端，支臂的另一端置于拖拉机悬挂支点上。

本挖坑机主要是对传统的悬挂式植树挖坑机的传动部分和挖掘部分的改进。在主轴箱设计方面，根据江苏50型拖拉机的传动参数，合理的设计锥齿轮的传动比以及强度计算等。在总体设计方面，尽量简化挖坑机的结构，减少其零件数目，以降低成本。对于双螺旋叶片设计，其直径由下往上逐渐减小，其螺旋夹角也由下往上逐渐减小，以避免钻头工作时与塘壁发生碰撞和摩擦等情况，提高了工作稳定性。

关键词：挖坑机；悬挂；双螺旋叶片

1WK-90-Type Planting Excavation Machine

Abstract: The digging machine of modern research and development of new main to the serialization, multi-functional and high-performance direction. The tree digging machine is currently used for a wide range of Jiangsu 50-wheel tractor designed package. Suspended digging machine with a tractor connected to a suspended three-point, that is, the bit at the end of suspension arm, the other end of the arm at the fulcrum of the flying tractor.

The digging machine is suspended from the traditional tree digging machine parts and the transmission part of the improvement of mining. In designing the spindle box, according to Jiangsu 50 tractor transmission parameters, and it needs a reasonable design of the bevel gear transmission ratio and the strength calculation. In the overall design, the digging machine tries to simplify the structure, reducing the number of its parts in order to reduce costs. Blade design for the double helix, whose diameter gradually decreases from bottom to top, the spiral angle also decreases from bottom to top in order to avoid the bit of work with the Tong-wall collisions and friction, etc., increased job stability.

Key words: Digging machine; Suspension; Double helix leaves

1 引言 1

1.1 本课题的设计意义 1

1.2 国内（外）发展概况及现状 1

1.3 课题由来及设计条件 2

1.4 课题设计思路 3

2总体方案设计 3

2.1整机构介绍 3

2.2 作业原理 3

2.3 挖穴机与拖拉机的联接 4

2.4 挖穴机的动力部分 4

2.4.1功率及挖坑幅度计算 5

2.5 挖坑机主要技术规格和基本技术参数 6

3部件设计 7

3.1 螺旋叶的设计 7

3.1.1 钻头的设计 7

3.1.2 双螺旋叶片的设计 7

4 设计计算 8

4.1动力分配计算 8

4.2 万向联轴器的选用计算 8

4.2.1 万向节总成 8

4.3 齿轮轴 8

4.4 轴承的选用与计算 10

5主要零件强度计算 12

5.1齿轮的校核计算 12

5.2 主轴的校核计算 15

6挖坑机使用和使用中的注意事项 21

6.1挖坑机使用 21

6.2使用中的注意事项 21

7结论 22

参考文献 23

致谢 24

附件清单 25

1 引言

1.1 本课题的设计意义

近年来，盐城拖拉机制造有限公司发展快速，年产3万台系列轮式拖拉机和8万台手扶拖拉机，销往国内30 个省、市和国外60多个国家和地区。如今，配套农用机具跟不上主机迅速发展的要求。其中包括1WK-50型轮式拖拉机，没有合适农机配套。因此，研制配套挖坑机与拖拉机同步销售，会使得拖拉机，挖坑机两旺。

我设计的是一台植树挖穴机，与黄海金马-50型拖拉机相匹配，用于植树造林及其他的小型挖坑作业。现有的挖穴机多为手提式挖穴机，起工作效率不高，使用条件不便，稳定性能不太理想，因此，本课题设计的植树挖穴机要求工作稳定，工作效率高。随着地球环境的日益恶化，需要大量植树造林，改善环境，因此，研制经济高效的植树挖穴机将深受广大人名群众的欢迎。

1.2 国内（外）发展概况及现状

中国挖穴机产业发展出现的问题中，许多情况不容乐观，如产业结构不合理、产业集中于劳动力密集型产品；技术密集型产品明显落后于发达工业国家；生产要素决定性作用正在削弱；产业能源消耗大、产出率低、环境污染严重、对自然资源破坏力大；企业总体规模偏小、技术创新能力薄弱、管理水平落后等。

我国植树造林机具现状我国植树造林机械赴较晚，主要在南方为种植橡胶实现产业化，有为东方红-75、热特-25型拖拉机配套的挖穴机，而北方地区为栽植果树和防护林，也研制了为中型轮式拖拉机如上海-50、神牛-25型拖拉机配套的开沟机、挖穴机，这种机具既可以挖植树穴坑，也可以挖梯形沟槽用于果树施沟肥。对大面积的机械植树造林，多采用铧式系歹开沟机，如1K-40、1K-50和1K-60型开沟机。我国植树造林机械虽有多个品种，但由于栽种树苗多在山地、坡地，土质条件复杂，影响了机械的使用效果，基本上用人工挖坑栽苗，生产的挖穴机批量较小。近几年来，由于经济林的兴起以及国家为防治水土流失，退耕还林、种草种树已引起各有关部门的普遍重视，并加大了植树造林机械的投入，取得了良好的效果。

挖穴机为了适应不同土壤、不同作业条件的要求，国外生产的不同动力配套的造林用挖穴机，有手提式、背负式、手扶拖拉机式和拖拉机式4种。

A.手提式挖穴机，分为单人式与双人式。日本多用单人手提式，欧洲各国则多采用双人手提式。手提式挖穴机发动机的功率一般为1.3--3.7kw，多采用油锯和割灌机的单缸风冷汽油发动机为动力。单人和双人手提式挖穴机发动机的转数经离心式离合器和减速箱，将转数降低到100--200r/min，再传到挖穴钻头。由于减速比很大，多采用蜗轮蜗杆或摆线针轮行星传动机构，以便减少机器的质量。由于双人手提式挖穴机质量可以大一些，有的采用多段直齿轮减速机构。有的挖穴机为了使挖穴机钻头能自动地由地中拔出，在传动机构中装有逆转机构。国外所用的挖穴钻头多为螺旋片型，挖穴时自穴中向上排土的性能好，螺旋片型有单螺旋和双螺旋两种。山地造林时，挖穴的直径和深度为25--30厘米，因此多采用1.5--2个节距的螺旋片。为了提高螺旋片型挖穴机的切根性能，有的将螺旋边缘做成缺口状。国外所用挖穴机钻头的转数都不太高，以免将穴中的土壤甩得过远，一般周边速度为3米/秒左右，钻头转数为200--300r/min。装有逆转机构的挖穴机在拔出钻头时，土壤会向相反方向旋转，不会从穴中抛出。手扶拖拉机式挖穴机的功率为3.7--7.3kw，轮式拖拉机挖穴机的功率为36.8--73.6kw。

B.悬挂式挖穴机主要用于栽植大树苗时的挖穴作业，挖穴直径为50--80厘米，挖穴深度为60厘米，挖穴机悬挂在25.7--58.8kw拖拉机上。挖穴机由纵吊杆、带安全装置的万向传动轴、减速器和不同直径的挖穴钻头组成。减速器由一对直齿锥齿轮组成，更换不同直径的挖穴钻头时，要更换不同的锥齿轮，可换挖穴钻头有3种，直径分别为80、60、30厘米。钻头由空心钻杆、叶片和切土刀片组成，钻杆下端有定心尖。工作时，由拖拉机动力输出轴经万向传动轴带动旋转工作部件完成挖穴作业，利用液压装置控制钻头升降。

C.液压式挖穴机在发达国家已普遍推广。由于液压技术的普及推广，发达国家在挖穴机上已采用液压传动装置，主要用在液压输出能力较强的拖拉机或挖掘机的机型上，用液压泵驱动齿轮机构传动系统。DANUSER液压挖穴机装有高效、转向密封性能好的液压马达，可调节机械链条与齿轮，使扭距增大4倍。采用液压驱动比用万向节套管传动更灵活方便，当遇到障碍物时能起到安全缓冲作用。

1.3 课题由来及设计条件

A.设计内容

设计一台植树挖穴机，与黄海金马-50型拖拉机相匹配，用于植树造林。主要的设计内容有：

a)总体设计:设计总体方案。绘制挖穴机总图；

b)零部件设计:根据挖坑机总图，设计齿轮箱等传动机构；绘制传动轴、齿轮、齿轮箱体、钻头等零件图；有关计算、校核等。

B.设计依据

a) 相配套的江苏-50型四轮拖拉机主要技术数据

①力输出轴转速:720r/min; 540 r/min

②动力输出轴离地高度:645mm

b) LY/T1491-1999,悬挂式挖穴机技术条件[S].

c) 挖穴机技术参数

①挖穴直径:70cm

②挖穴深度：70cm

③钻头转速：150～250r/min

④钻头形式：采用双螺旋叶片结构；

⑤工作效率：60～90坑塘/小时

⑥按5年寿命，每年工作800小时计。

C.设计要求

a) 挖穴机与拖拉机采用三点悬挂联接，作业时万向传动轴偏置角度不得大于15°，田间移位或运输前必须先切断动力，将螺旋钻头提升至最大高度，此时钻头顶尖离地高度应大于300mm。

b) 螺旋叶片的转速过高，会将泥土抛得很远，造成填坑缺土。转速过低，则造成工作效率不高。因此在设计时，要充分调研和实践，确定合适的转速，

c) 为保证工作性能，设计时应充分考虑其稳定性，避免受力不均匀而造成抖动；

d) 结构简单可靠，尽量使用标准件、通用件，以降低制造成本。

1.4 课题设计思路

在开始该机设计前，参考对比了一系列已有的植树挖穴机，例如悬挂式挖穴机，手提式挖穴机，液压式挖穴机等，总结发现他们都要用到由一对齿轮传动组成的减速箱，而本课题采用的是悬挂式挖穴机的方式，一种与小四轮拖拉机配套的悬挂式挖坑机，由悬挂架、带安全装置的万向传动轴、减速箱、双螺旋叶片型钻头等构成；悬挂架两端分别与拖拉机和减速箱铰合连接，双螺旋型钻头固定在减速箱的输出轴上；工作时，拖拉机的提升臂拖带悬挂架进行升降，由拖拉机动力输出轴经万向传动轴带动旋转工作部件完成挖穴作业；具有结构简单、作业质量好、效率高、移动及通过性能灵活的特点，广泛应用于植树造林、施肥集水、埋设桩柱等作业。

2总体方案设计

2.1整机构介绍

一种与小四轮拖拉机配套的悬挂式挖坑机，由悬挂架、带安全装置的万向传动轴、减速箱、双螺旋型钻头等构成，减速箱由一对锥齿轮传动组成。

2.2 作业原理

一种与小四轮拖拉机配套的悬挂式挖坑机，由悬挂架、带安全装置的万向传动轴、减速箱、双螺旋型钻头等构成；悬挂架两端分别与拖拉机和减速箱铰合连接，双螺旋型钻头固定在减速箱的输出轴上；工作时，拖拉机的提升臂拖带悬挂架进行升降，由拖拉机动力输出轴经万向传动轴带动旋转工作部件完成挖穴作业；具有结构简单、作业质量好、效率高、移动及通过性能灵活的特点，广泛应用于植树造林、施肥集水、埋设桩柱等作业。

挖坑作业时，拖拉机液压悬挂装置处于浮动状态，使钻头对准挖坑标记中心靠自重下落，拖拉机的动力输出轴通过传动轴和减速器带动钻头旋转入土，钻头切去中心部分土壤，进而钻头叶片下端的刀片切削土壤，切下的土壤在离心力作用下被抛向穴壁，并在摩擦力作用下沿着叶片螺旋向上升到地面被抛到穴的周围，挖到预定深度时，通过液压悬挂装置提升钻头到运输状态，再转移到下一个挖坑地点。

2.3 挖穴机与拖拉机的联接

挖穴机与拖拉机采用三点悬挂装置联接，具有结构简单、作业质量好、效率高、移动及通过性能灵活的特点，广泛应用于植树造林、施肥集水、埋设桩柱等作业。

全部文件.png

田间工作作业图(A2).gif

田间作业状态图(A2).gif

总装图（A0）.gif

钻头焊合（A3).gif

A1箱体.gif

A4大端盖.gif

A4隔套Ⅰ.gif

齿轮箱（A1).gif

大齿轮（A3）.gif

封板（A4）.gif

加强肋.gif

支臂.gif

轴承端盖焊合（A3）.gif

轴承座（A3).gif

内容简介：: -1Tree establishment and growth using forage ground covers in an alley-croppedsystem in Midwestern USAKathleen Delate1,*, Eric Holzmueller2, DeAnn Davis Frederick1, Carl Mize3and CharlesBrummer11Department of Agronomy, University of Florida, Gainesville, FL 32611, USA;2School of Forest Resourcesand Conservation, University of Florida, Gainesville, FL 32611, USA;3Department of Natural ResourceEcology and Management, Iowa State University, Ames, IA 50011, USA; *Author for correspondence(e-mail: kdelate; phone: 515 294-7069; Fax: 515 294-0730)Received 27 May 2003; accepted in revised form 21 October 2004Key words: Black walnut, Fescue, Oak, Poplar, Red clover, Silver mapleAbstractThe integration of forage crops in an alley-cropped system was examined as a method of encouraging treeplanting to increase farm income, improve soil quality, and enhance biodiversity on Midwestern U.S.farms. Crop and tree performance were evaluated in an alley-cropped system using four forage intercropsgrown in tree alleyways to simulate a potential hay crop oat (Avena sativa L.) and red clover (Trifoliumpratense L.); oat, red clover, and red fescue (Festuca rubra L.); oat, red clover, and orchardgrass (Dactylisglomerata L.); and oat and hairy vetch (Vicia villosa Roth) compared to a herbicide, mowing and control(no management) treatment. Five tree species, divided into fast-growing hardwoods of two poplar (Populusspp.) clones Crandon (P. alba L. P. grandidentata Michx.) and Eugenei (P. deltoids Bartr. P. nigraL.), and silver maple (Acer saccharinum L.) were compared with two high-value, slow-growing hardwoodsplanted from seed and as seedlings: red oak (Quercus rubra L.) and black walnut (Juglans nigra L.). Treesurvival in the first year was greater for the fast-growing species, and by the fourth year, tree height amongthe four forage treatments was equivalent for all upland locations. The oat/hairy vetch ground cover wasassociated with the shortest trees in the bottomland site. Herbicide-treated trees were taller than the averageof the four forage treatments for all four planting conditions. Tree height in the mowing and the controltreatments was not significantly dierent for all four planting conditions. The nutritive value of the foragecrop was excellent in the second year of tree establishment, with crude protein content and digestibility at17 and 71%, respectively, in the oat/red clover/red fescue treatment, suggesting the viability of forage cropsas alternatives to herbicides in alley-cropped systems.IntroductionThe demand for continuous production of com-modity crops has led to depauperate native andintroduced tree populations on Midwestern U.S.farms (Van Der Linden and Farrar 1993). Theintegration of trees with agronomic crops has beenactivelypromotedthroughouttheworldtoincreasebiodiversity, to optimize production and resourceconservation, and to improve wildlife habitat(USDA 2004). Alley-cropping of trees within cropfields or pasture systems has been shown to be aneconomical method of re-integrating trees intothe farm landscape (Nair et al. 1995). SoilAgroforestry Systems (2005) 65:4352 C211 Springer 2005DOI 10.1007/s10457-004-5228-ximprovement, enhanced crop yields, and increasedfarm income have been reported from alley-crop-ped systems (Gordon and Williams 1991). Lesscompetitive, forage-based agroforestry systemshavebeenshowntobemorecompatiblethangrain-crop-based alley-cropping systems, due to theshading from mature tree species having a greaterimpactongraincropscomparedtoforages(Garrettand Kurtz 1983; Gillespie 1996). Greater systemproductivity (increased timber production, highercrop yields and/or livestock growth) has been ob-tained in various silvopastoral systems, includingcattle grazing under loblolly pine (Pinus taeda L.)(Harwell and Dangerfield 1991), subterranean clo-ver (Trifolium subterraneum L.) intercropped withDouglas-fir (Pseudotsuga menziesii L.) (Sharrowet al. 1996), rhizoma-peanut (Arachis glabrata L.)under pine (Pinus spp.) (Johnson et al. 1994), tallfescue (Festuca arundinacea L.) and orchardgrass(Dactylis glomerata L.) under mature (35-yr-old)black walnut (Garrett and Kurtz 1983), and redclover with black walnut and honeylocust trees(Gleditsia triacanthos L.) (Alley et al. 1999).During the critical period of tree establishment,competition from weeds or living ground coversfor nutrients, light, and water can severely hindertree survival and growth. Traditional methods,such as herbicide applications, have proven eec-tive in controlling weed populations (Cogliastroet al. 1990), but herbicides are not universallyaordable, may cause phytotoxicity in cultivatedplantings, and have limited eects on maintainingsoil quality (Pimentel et al. 1995).Forage yields in silvopastoral systems alsodepend on sucient forage establishment andmanagement, including managing shading eectsfrom trees. Frequency of cutting or grazing undertrees must be based on the shade tolerance andconcomitant growth rate of pasture species.Genotypic responses of forages to shading haveranged from a negative to equal growth ratecompared to non-shaded plants (Thompson 1993).Nitrogen content was shown to increase in le-gumes under shade, while dry matter, leaf area andstem length increased in shade-grown grasses(Kephart and Buxton 1993).Overall benefits from the integration of foragespecies in agroforestry systems include facilitationof mutual growth of tree and hay crops, potentialrevenue from dual crops, and increased carbonstorage from grass and legume species. Theobjectives of this experiment were fourfold: (1) toevaluate the eect of four forage mixtures onsurvival and growth of trees, compared to mow-ing, herbicides, or no weed management in analley-cropped system in Iowa; (2) to determine theperformance of each forage mixture in tree alleysbetween seven tree types; (3) to evaluate growthand survival of propagative material (tree seeds vs.seedlings) in this system; and (4) to determine thenutritive value of the forage crop harvested fromthe tree alleys.Materials and methodsStudy site and designThe field research was conducted at the Iowa StateUniversity Rhodes Research Farm, near Rhodes,IA. Moderately uniform upland and bottomlandsites (0.8 ha each) were selected for planting in thespring of 1998. The predominant soils on the up-land site were Downs soil (fine-silty, mixed, mesicMollic Hapludalf) and Gara (fine-loamy, mixed,superactive, mesic Mollic Hapludalf) on the bot-tomland site. Sites were selected on former pastureground of mediumhigh fertility that was plowedin the spring of 1998 to kill existing vegetation andcreate a suitable seedbed for the experiment.Seven ground management treatments, made upof four forage mixtures: (i) oat and red clover; (ii)oat, red clover, and red fescue; (iii) oat, red clover,and orchardgrass; and (iv) oat and hairy vetch,and (v) herbicide, (vi) mowing and (vii) a control(no management) were compared. Five tree spe-cies, divided into two groups fast-growing andslow-growing were evaluated in this system. Thefirst group (fast-growing hardwoods) containedsilver maple and two poplar clones, Crandon andEugenei. The second group consisted of two high-value, slow-growing hardwoods planted from seedand as seedlings: red oak and black walnut.The upland and bottomland sites were eachdivided into six blocks. On each site, three blockswere planted with fast-growing trees, and threeblocks were planted with slow-growing trees. Theoverall design was four randomized completeblock experiments with three blocks per experi-ment. Fast-growing tree blocks were established ina split-plot design, with ground management asthe whole plot treatments and tree species as the44sub-plot treatments. Slow-growing tree blockswere established in a split-split plot design, withground management as the whole plot treatments,tree species as the sub-plot treatments, and prop-agative material (seed vs. seedling) as the sub-sub-plot treatments.The whole plots for fast-growing trees were7.3 m 33.5 m, and the tree species were ran-domly assigned to subplots within each whole plot.Tree spacing within plots was 0.9 m 3.9 m. Thewhole plots for slow-growing trees were7.3 m 30.5 m. Tree spacing within plots was ei-ther 0.6 m 3.9 m (seedlings) or 15 cm 3.9 m(seeds). The plots for slow-growing trees weredivided into two subplots, and the subplots wererandomly assigned to be planted with either seedor seedlings. The subplots were divided into twosub-subplots, which were randomly assigned to beplanted to either red oak or black walnut.Whole plots were seeded on 5 May 1998 with agrain drill (oat seed) and a BrillionTMdrill (forageseed). Oat (Ogle), red fescue (Flyer), red clover(Marathon), and orchardgrass (Duke) seedswere planted at 72, 4, 11, and 7 kg haC01, respec-tively. After seeding the forage treatments, treeswere planted in two rows, 3.9 m apart, in all wholeplots. Each row of trees was planted 1.7 m fromthe edge of the whole plot, and the 1.7-m of edgefunctioned as the unsown buer area between treesin whole plots or between trees and areas outsidethe blocks. For each fast-growing species, eightseedlings per row were planted 0.9 m apart. Theslow-growing species had nine seedlings per rowplanted 0.6 m apart and 35 seeds planted 15 cmapart per row. In all, 3528 seedlings and 5900 seedswere planted on 79 May 1998. Slow-growingspecies were planted with narrow spacing betweenseedlings and seeds in order to secure adequatenumbers of seedlings in each plot to estimate first-year mortality with reasonable precision.The herbicide treatment consisted of a 1.5-m-wide weed-free strip centered on each row ofseedlings, created by applying oxyfluorofen(1.1 kg haC01) and pendimethalin (2.25 kg haC01)immediately after planting in the first year, andsimazine (2.25 kg haC01) and pendimethalin(2.25 kg haC01) applied each spring in the second tofourth years. Glyphosate was applied, whenneeded, to any weeds in the strip that emergedduring the season. The remaining two groundmanagement treatments consisted of mowingwhen weeds were 20 cm in height and the control(no management). In order to reduce weed com-petition and promote forage growth, plots weremowed in July, August, and November 1998, andat approximately the same time during the secondthrough fourth years. Forage samples were takenin the second year of establishment, at which timeplots were mowed after sampling events. Cut for-age material was not removed from the plots (ex-cept for samples) due to low yields. On 16 May1998, an electric fence (three-strand) was erectedaround the perimeter of each site to preventbrowsing by deer and cattle in the area.Tree seedlings were planted at twice the normaldensity for initial establishment in 1998 and thin-ned to the target population of 50% of initialplanting rate in 1999. Seedling trees were thinnedon 14 and 15 May 1999 by manually clipping everyother tree and applying glyphosate herbicide totree bases to prevent re-growth. Seedlings fromseed were not thinned.Measurements: treesTree survival was determined, and diameter andheight were measured, at the end of the growingseasons in SeptemberOctober of 19982001. Treeheight was measured to the closest 5 cm, using amarked PVC pole, with the terminal bud as theprimary reference point. Diameter of the trees,except red oak trees from seed, which were gen-erally too short to be measured, was measured at20 cm above ground level.Measurements: forage yield and nutritive qualityForage biomass accumulation was measured inthree randomly selected areas in each of the foragetreatments on 23 June, 14 July, and 17 September1999. Forage samples were taken from tree alleys,representative of areas where hay crops would bemowed. An estimate of forage height was deter-mined by measuring forage plants in the 0.1-m2quadrat with a hand-held meter stick with thehighest terminal bud as the primary referencepoint. Yield was estimated by hand-clipping for-ages under the 0.1-m2quadrat. Clipped foragesamples were placed in paper bags for transportand further laboratory analysis. For each45treatment within tree type, five sub-samples weretaken on 23 June, six on 14 July, and twelve on 17September 1999. After forage samples were driedat 60 C176C for 5 days, dry matter yield was deter-mined. Samples were then separated into legumeor grass components. Each component wasground through a Wiley Mill (Thomas Manufac-turing, Philadelphia, PA) to pass through an 8-mmscreen and a Cyclone Mill (UDY Manufacturing,Fort Collins, CO) to pass through a 1-mm screen.The ground samples were stored in plastic jarsuntil analyzed. Crude protein and in vitro digest-ible dry matter (IVDDM) were determined by themicro-Kjeldahl method (Bremner and Breitenbeck1983) and the two-stage IVDDM method (Martenand Barnes 1980), respectively. Rumen fluid wascollected on the day of inoculation from a fistu-lated steer that was fed a 100% hay diet.Statistical analysisTree data were analyzed separately for the fourexperimental groups: upland slow-growing, up-land fast-growing, bottomland slow-growing, andbottomland fast-growing. Analysis of variance wasused to test for interactions between the speciesand ground treatments and main eects (SASInstitute 1989). The arcsin of the percentage sur-vival was analyzed to increase homogeneity ofvariances (Snedecor and Cochran 1980). Duncanstest was used to compare treatment means amongspecies and treatments for the first and fourthyears results (Snedecor and Cochran 1980).Planned contrasts (Snedecor and Cochran 1980)were performed to compare tree height after fourgrowing seasons in the following groups: controlvs. mowing; forage treatments vs. control andmowing; forage treatments vs. herbicide treatment;and the four forage treatments (SAS Institute1992).ResultsTree survivalAt the end of 1998 (Year 1) survival rates for fast-growing trees in the upland site were greater forEugenei than Crandon and silver maple (Table 1).In the bottomland location, survival rates werealso greater for Eugenei than silver maple, andsilver maple was greater than Crandon (Table 1).First year survival rates were not aected byground management treatments in the bottomlandlocation (p = 0.57), but on the upland site therewas a significant management treatment eect(p = 0.002) in which the herbicide treatment waslowest with 69% survival while the other treatmentmeans were not dierent (averaging 93%). Therewas no management treatment by species interac-tion for the bottomland site (p = 0.57), but therewas an indication of a management treatment byspecies interaction on the upland site (p = 0.049),which seemed to result from silver maple seedlingshaving similar survival for all management treat-ments while survival of the other species was morevariable among the management treatments. AfterTable 1. Tree survival and growth of fast-growing tree species in a Midwestern USA alley-cropped system.First year Fourth yearEugenei Crandon Silver maple SE Eugenei Crandon Silver maple SEUpland siteSurvival (%) 95aA85b 89b 1 BBBBHeight (m) 0.27b 0.32a 0.20c 0.01 3.5b 5.1a C0.1Diameter (cm) BBBB1.0b 1.7a C0.05Bottomland siteSurvival (%) 97a 76c 90b 2 BBBBHeight (m) 0.53a 0.39b 0.26c 0.02 6.1a 5.7b 2.6c 0.1Diameter (cm) BBBB2.2a 1.9b D0.05ATreatment means followed by the same letter in the same row in the same year are not statistically dierent at p 0.05.BData not taken in this year.CSilver maple on upland site was heavily browsed by deer; height and diameter not measured in Year 4.DSilver maple developed many small stems; diameter not measured.46four years of growth (Year 4), survival for the fast-growing species was quite high (8097%) on bothsites, with no dierences evident among groundtreatments or species (p 0.28).On upland and bottomland sites, combinedrates of survival for red oak and black walnutseedlings in Year 1 were similar and greater thanestablishment of seedlings from seeds of thosespecies (Table 2). On the upland site, black walnutfrom seed had higher establishment rates than redoak, but on the bottomland site their establish-ment rates were similar (Table 2). Slow-growingtree survival rates did not dier among manage-ment treatments on the bottomland site (p = 0.38)but there was an indication of a dierence(p = 0.06) on the upland site, due to variability inthe response of the trees to the managementtreatment. There were no management treatmentby species interactions for the upland (p = 0.98)nor the bottomland (p = 0.57) sites.Because the number of surviving red oak seed-lings from seed was so low (1.7% of sown seed inthe bottomland and 1.2% on the upland), withmany of the plots having no surviving seedlings,this treatment was dropped from the experiment.Thirty-one percent of the black walnut seed thatproduced a seedling in the first year survivedthrough the fourth growing season, and there wereno dierences in black walnut survival ratesamong ground treatments on either site (p 0.75).Tree sizeAt the end of Year 1, Crandon height exceededEugenei, which in turn was greater than silvermaple in the upland location (Table 1). On thebottomland site, Eugenei height was greatest, fol-lowed by Crandon and silver maple (Table 1). Onboth sites, the ground treatments resulted inmodest dierences among average heights, with notreatment clearly better than the others. On thebottomland site, there was no ground treatment byspecies interaction (p = 0.97), but the upland sitehad an interaction (p = 0.049) that seemed to re-sult from the silver maple height being relativelyunaected by the ground treatments, possibly dueto browsing by deer, while the height of the otherspecies varied somewhat among treatments. Be-cause of heavy browsing by deer on the uplandsite, and the resulting minimal increases in heightin the silver maple trees after 4 years of growth,this treatment was dropped from the fourth yearanalyses. Of the other fast-growing species, Cran-

温馨提示:
1: 本站所有资源如无特殊说明，都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等，如果需要附件，请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸，网页内容里面会有图纸预览，若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供信息存储空间，仅对用户上传内容的表现方式做保护处理，对用户上传分享的文档内容本身不做任何修改或编辑，并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容，请与我们联系，我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

人人文库网所有资源均是用户自行上传分享，仅供网友学习交流，未经上传用户书面授权，请勿作他用。