烟秆拔除机的设计仿真与试验研究

针对烟田中烟秆的拔除难度大、拔除效率低等问题,采用三维建模软件Solid Works设计了一种新型烟秆拔除机,拔秆装置由一对不同旋向的笼状鼓形旋刀组成,可一次性完成拔秆、除土、平垄及覆盖杂草等作业;同时,利用机械系统动力学分析软件ADAMS对拔秆装置进行运动学仿真。仿真结果表明:机具作业轨迹曲线稳定,1个时间周期内沿X轴方向(机具前进方向)的位移变化量为400.5mm,验证了机具结构设计的合理性,且符合实际作业情况。田间性能试验表明:机具的通过性良好,作业效率为0.42hm2/h,烟秆断蔸率为1 0.2%,附土率为15.6%,效果远远优于人工拔除作业。     

VR在机械领域中如何实现三维虚拟教学探究

现如今风靡全球的VR虚拟现实科技,已经渗透到城市规划、医疗科技、机械制造、影视娱乐、游戏动漫等多个领域中,并且为其提供所需要的方案和规划等。有专家预测将来的十年内,每个行业几乎都会受到VR科技的影响,而教育培训行业将会是重点应用领域。文章将对其在机械领域中的三维虚拟教学进行探究。     

Plant-available water and integral energy for Medicago sativa and Bromus tomentellus in texturally different soils

Soil water availability is very crucial for pasture plants because their growth solely depends on the soil water storage. While plant-available water (PAW) is successfully related to plant growth, it is the energy required per unit mass of water, integrated over the PAW range, named the integral energy (E_I) that determines how easily plants can take up water from the soil. The soil water retention function was integrated over the PAW range to calculate the E_I. PAW and E_I were determined for Medicago sativa (alfalfa, a legume) and Bromus tomentellus (a grass) species in five texturally different soils of semi-steppe rangeland in central Zagros, western Iran. The PAW was calculated as the difference between field capacity and permanent wilting point (nominal h of 15,000 hPa or actual h obtained from PWP value determined in greenhouse). E_I values were calculated for the nominal and actual PAW values. M. sativa PAW and E_I values were more than those from B. tomentellus, indicating that M. sativa was able to tolerate higher soil matric suctions at similar conditions. Results showed predicting E_I only from basic soil properties is not accurate. PAW and E_I are dependent on plant species and soil type interactions, and environmental compatibility.     

临洮县生产建设项目弃渣场土壤流失特征——以肖家河水电站二期工程为例

[目的]探讨水电类生产建设项目弃渣场坡面水土流失特性,为黄土丘陵区生产建设项目水土保持综合治理提供科学的理论依据。[方法]以甘肃省定西市临洮县2013年降雨数据为依托,通过肖家河水电站二期工程径流小区对不同处理下的水土流失特征进行研究。[结果](1)临洮县2013年降水量为580.2mm,定义为平雨年;(2)研究区降雨量和平均降雨强度的乘积与土壤侵蚀量呈线性正相关关系(相关系数大于0.85);(3)不同植被类型对弃渣场水土流失有影响,其中油松与苜蓿混播能有效降低土壤侵蚀量和径流量;(4)表层土前期含水量对弃渣场土壤流失量有显著影响,下层土前期含水量对弃渣场土壤流失量无显著影响。[结论]水电类生产建设项目弃渣场土壤流失受降雨量和降雨时间乘积、植被类型和表层土前期土壤含水量的影响。     

秸秆深还对土壤水分转移及产量的影响

采用田间试验方法,将玉米秸秆切段、粗粉碎、细粉碎、细粉碎后压粒和细粉碎后氨化处理,研究玉米秸秆深施还田对土壤水分转移及产量的影响。结果表明,秸秆粉碎程度越细,吸水能力越强,深施后土壤渗水速度越快;粉碎的秸秆较其他处理更能促进土壤水分竖直方向转移;各处理的蓄水能力表现为粉碎状秸秆处理段状秸秆处理CK(不施秸秆),且细粉碎、细粉碎后氨化处理在还田初期就能呈现出明显的蓄水效果;秸秆粉碎状态越细,深施后土壤容重减小的速度和幅度越大,细粉碎处理和细粉碎后氨化处理能在还田初期对减小土壤容重产生明显作用,播种后25 d,土壤容重减小幅度最大,分别达0.052和0.045 g/cm3;秸秆深施还田有效提高玉米产量,产量排序为细粉碎细粉碎后氨化处理粗粉碎细粉碎后压粒秸秆切段CK(不施秸秆),其中细粉碎处理对玉米产量的增加影响最明显。     

赣北棉区棉花与马铃薯连作高效栽培模式

通过选择多点调查,对棉花与马铃薯连作与当地常年的习惯栽培模式（油棉、麦棉）作效益比较。结果表明：棉田冬闲时种植马铃薯是较为理想的复种模式,其棉田效益达71190元/hm2,比油棉和麦棉分别增加收益35160和35880元/hm2,有利于稳棉增粮,适合在赣北棉区推广应用。     

山西中南部一次暴雪过程诊断分析

为了进一步分析山西中南部暴雪过程的形成原因,笔者利用常规和非常规气象观测与监测资料,针对2014年2月4—6日山西中南部暴雪天气过程,从高空、地面天气形势、中低层流型配置、雷达回波及物理量场的空间垂直剖面进行综合分析。结果显示：该次暴雪过程以500hPa西风槽、南支槽相继影响、地面倒槽前部东南气流的控制为背景。500hPa西风槽,700hPa西南急流与横切,850hPa东南急流为该次暴雪的中尺度有利配置。回波强度在15~30dBz,属连续均匀的稳定性降雪回波。物理量场的相对湿度在200hPa以下为大于80%的湿空气柱、对流层为一致的上升运动、高层辐散与低层辐合构成了有利于强降雪的环境条件。     

长期施肥对洞庭湖双季稻区水稻土有机碳、氮积累及其活性的影响

【目的】土壤有机质及其活性是评价土壤肥力的重要指标,研究洞庭湖区典型双季稻轮作水稻土总有机碳、全氮积累及其活性对长期不同施肥的响应特征,为稻田施肥管理和土壤培肥提供科学依据。【方法】依托国家稻田土壤肥力与施肥效应长期试验平台,以不施肥处理（CK）为对照,研究农户习惯施氮磷钾化肥（CF）、施氮钾化肥（NK）、均衡施氮磷钾化肥（NPK）、低量有机肥与氮磷钾化肥配施（LOM,有机肥氮比例为30%）、高量有机肥与氮磷钾化肥配施（HOM,有机肥氮比例为60%）影响下0-20和20-40 cm土层土壤总有机碳（TOC）、全氮（TN）含量及储量积累效应、有机碳氮活性组分含量及其比例的变化特征。【结果】26年不施肥0-20 cm土层土壤TOC含量基本稳定,仅较原始土壤增加0.64 g·kg^-1,持续植稻可能是其保持稳定的重要原因。两土层土壤TOC、TN含量在长期不同施肥后均有显著增加（P＜0.05）,但其储量仅仅在均衡施氮磷钾化肥特别是与有机肥配施后显著提升（P＜0.05）。0-40 cm土层土壤微生物量碳（MBC）、微生物量氮（MBN）、溶解性有机碳（DOC）、溶解性有机氮（DON）含量变幅分别为64.54-708.76、22.92-92.25、39.06-63.24、10.76-31.87 mg·kg^-1,均随土层加深而下降。施肥后0-20 cm土层土壤MBC、MBN、DOC、DON含量提高34.1%-81.8%、56.1%-134.4%、23.5%-42.0%、20.3%-83.2%,20-40 cm土层则分别提高-3.8%-38.1%、32.5%-78.2%、8.2%-37.5%、9.3%-56.8%,施肥对相同土层土壤MBC、MBN、DOC、DON含量的增加效应均表现出氮磷钾化肥配施有机肥明显优于化肥单施的处理效应,但不同化肥处理间0-20 cm土层土壤微生物量碳氮、溶解性有机碳氮含量差异不显著（P＞0.05）。随土层加深,土壤MBC/TOC、MBN/TN、DON/TN数值显著降低,而DOC/TOC值则有所增加。长期不同施肥有利于提升土壤总有机碳、全氮中活性组分比例,且以氮磷钾化肥配施有机肥处理效果最佳,其两土层土壤总有机碳、全氮中各活性碳氮组分的分配比例均较CK处理显著提高（P＜0.05）,且该效应随有机肥用量增加而增强。土壤MBC、MBN、DOC、DON两两之间及与土壤总有机碳、全氮、容重、pH具有显著或极显著相关性,与碳氮比、粘粒含量的相关关系不显著,但总体以土壤微生物量碳氮所获相关系数高于溶解性有机碳氮。施肥明显提高早、晚稻产量,两土层MBC、MBN、DOC、DON均与周年水稻产量呈现正相关性,但相关系数总体上随土层加深而明显降低（P＜0.05）。【结论】在洞庭湖双季稻区,长期不同施肥后,相同类型土壤活性有机质组分中活性氮组分含量增加较活性碳组分更明显,氮磷钾化肥配施有机肥能显著提高0-40 cm土层土壤有机碳、氮活性,更有利于土壤总有机碳氮积累及生产力提升,土壤微生物量碳氮可更敏感地预测长期施肥影响下土壤质量的变化。     

绿盲蝽交配干扰剂丁酸己酯微囊的制备及田间防治效果

以乙基纤维素为壁材,丁酸己酯为芯材,采用相分离法制备了绿盲蝽Apolygus lucorum交配干扰剂丁酸己酯微囊。通过正交试验研究了乳化剂700#、聚乙烯醇、乙酸乙酯及控释剂正十二烷4个因素对丁酸己酯微囊形成的影响,得到最佳制备工艺条件。利用生物显微镜对微囊的形态进行了观察,同时测定了在最优条件下制备的丁酸己酯微囊的载药量、包封率和释放速率等指标,并进行了田间药效试验。结果表明:在乙基纤维素3.0 g、丁酸己酯3.0 g、乳化剂700#1.5 g、聚乙烯醇2.0 g、乙酸乙酯30 m L和正十二烷2.0 g,以及滴加速率为5 m L/min、转速为1 000 r/min条件下制备的丁酸己酯微囊的载药量和包封率分别为21.5%和91.9%,外观较完整,粒径分布较均匀,平均粒径约为301.85μm,缓释效果较好(能持续释放35 d以上)。田间试验结果显示,调查期间悬挂丁酸己酯微囊的样区诱捕到绿盲蝽224头,与对照区相比少442头,表明丁酸己酯微囊对绿盲蝽交配具有干扰作用,可明显减少绿盲蝽繁殖的数量。     

Ecophysiological characteristics of five weeds and a wheat crop in the Indo‐Gangetic Plains,India

The objective of this research was to compare selected ecophysiological parameters for a wheat crop found in the Indo‐Gangetic Plains of India and its five dominant weeds. The dominant and regionally ubiquitous weeds in the wheat field that was selected for the study were Anagallis arvensis, Chenopodium album, Melilotus albus, Phalaris minor and Rumex dentatus. Taller weeds, such as C. album and P. minor, constituted one group along with the crop, with a low photosynthetic rate, specific leaf area, leaf nitrogen mass basis, chlorophyll content, photosynthetic nitrogen‐use efficiency and leaf area ratio, in comparison to shorter weeds, such as A. arvensis, M. albus and R. dentatus, which formed another group with a high photosynthetic rate, specific leaf area, leaf nitrogen mass basis, chlorophyll content, photosynthetic nitrogen‐use efficiency and leaf area ratio. Interspecific variations in the photosynthetic rate were driven mainly by variability in the specific leaf area and leaf nitrogen content. The taller weeds and the crop had a low specific leaf area later in the season, whereas the smaller weeds had a relatively high specific leaf area, which might be an adaptation to the shaded environment below the canopy. The result indicates that any weed management in the wheat fields of the Indo‐Gangetic Plains will need two different approaches because of the different strategies followed by the two weed groups that were identified in the present study.