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Growth characteristics of multipurpose tree species, crop productivity and soil properties in agroforestry systems under subtropical humid climate in India 被引量:3
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作者 M. Datta N. P. Singh 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第4期261-270,共10页
Multipurpose tree species (MPTs) were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2... Multipurpose tree species (MPTs) were studied in an agroforestry arboretum under subtropical humid climate in Northeast India. Out of 12 MPTs planted under agroforestry systems, Acacia auriculiformis in spacing of 2 m × 2 m (2500 stems·hm^-2) could have the potentiality to meet the timber/fuelwood requirement due to its high wood production of 635 m^3·hm^-2 with mean annual increment (MAI) of 2.54×10^-2 m^3.treel.a^-1 in a short rotation period of 10 years. Thus, A. auriculiformis is a short rotation forest tree species suitable to grow in subtropical humid climate. On the other hand, at 16 years of age, Eucalyptus hybrid and Michelia champaca in spacing of 3 m × 3 m (1111 stems.hm^2) produced appreciably high timber volume of 315 m^3.hm^-2 and 165 m^3.hm^-2 with MAI of 1.77×10^-2 m^3.tree^-1·a^-1 and 0.92×10.2 m^3.tree^-1.a^-1, respectively. At 16 years of age, Gmelina arborea produced a timber volume of 147 m^3.hm^-2 with MAI of 1.47×10^-2 m^3.tree^-1.a^-1 followed by Samania saman (140 m^3.hm^-2), Albizziaprocera (113 m^3·hm^-2) and Tectona grandis (79 m3.hm^-2) with MAI of 1.40, 1.13 and 0.78 × 10^-2 m^3 .tree^-1a^-1, respectively in 4 m × 4 m spacing (625 stems.hm^-2). Gliricidia maculata and Leucaena leucocephala could be used as live fences around the farm boundary to supply their N-rich leaves for mulch as well as manure to crops. In agroforestry arboretum, direct seeded upland rice (Oryza sativa - variety, AR-11), groundnut (Arachis hypogaea - variety, JL-24) and sesamum (Sesamum indicum - variety, B-67) were grown during the initial period upto 8 years of tree establishment. Under other MPTs, there was a reduction in crop productivity as compared to open space. After 8 years of tree establishment, horti-silvi and silvi-pastoral systems were developed and pineapple (Ananas comosus - variety Queen), turmeric (Curcuma longa -variety RCT -1) and cowpea (Vigna sinensis - variety Pusa Barsati) as forage crop were raised. The productivity of p 展开更多
关键词 multipurpose trees Subtropical humid climate Growth characteristics Timber volume Crop productivity Soil organic car-bon Soil humus Nutrient availability Soil erodibility indices Soil moisture.
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基于Soildworks的多用途货车设计
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作者 王花兰 王泽宇 +1 位作者 张晓龙 陈瑞 《兰州交通大学学报》 CAS 2013年第3期94-98,共5页
针对我国铁路货车空走行率高、敞车与平车代用现象较为严重的情况,设计了多用途货车.该车在NX17BK车底架的基础上,设计了两端凹形多节伸缩墙和两侧中部多节伸缩墙,墙体可由自动升降系统完成升降.当墙体完全升起时,车体同普通敞车;墙体... 针对我国铁路货车空走行率高、敞车与平车代用现象较为严重的情况,设计了多用途货车.该车在NX17BK车底架的基础上,设计了两端凹形多节伸缩墙和两侧中部多节伸缩墙,墙体可由自动升降系统完成升降.当墙体完全升起时,车体同普通敞车;墙体全部降下时车体成为装运集装箱以及笨重大件货物的两用平车.车体设计完成后,运用Soildworks软件绘制车体的三维模型.最后,计算墙体在静载、动载、冲击三种列车工况下的载荷,通过Solidworks Simulation Professional将载荷植入该车的三维实体模型节点集合中进行有限元结构分析,完成了车体强度、刚度检验,绘制了不同工况下车体横向1/2子模型应力云图和位移云图.结果表明所设计的多用途货车在各种工况下的最大应力和位移均符合《TB/T1335-1996铁道车辆强度设计及试验鉴定规范》规定. 展开更多
关键词 多用途货车 SOLIDWORKS 墙体设计 三维模型 有限元分析
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