多自由度剑麻收割机的设计与仿真制造

剑麻是一种广泛使用的硬质纤维的主要来源,被广泛的运用到各种行业,需求极大;但其收割现以手工为主,且因剑麻自身带有刺,加大了收割的难度,降低了效率。为解决剑麻的纯手工收割收割困难以及效率低的问题,提出一种多自由度剑麻收割机的机械,并申请了国家发明专利,得到授权。本文将运用UG、Sdams以及Mat Leb对该机械进行改进设计与仿真分析,并试制实物机械进行试验。试验结果表明:该机实现了剑麻收割的半自动化并提高剑麻收割的效率,可满足现行各行各业对剑麻的需求量。     

甘蔗收获机切割系统负载压力影响因素的试验研究

针对甘蔗收获机在入土切割时无法根据地形精确控制切割器入土切割深度的问题,通过理论分析甘蔗收割机入土切割时影响切割系统负载压力的因素,并通过试验探究各因素对切割系统负载压力的影响规律。试验结果表明:影响切割系统负载压力的主要因素有入土深度、土槽进给速度、甘蔗密度、刀盘转速、土壤含水率和土壤密度,随着入土切割深度、土槽进给速度、甘蔗密度和刀盘转速的增加,切割系统的负载压力整体均呈逐渐增大的趋势,并得出各因素对切割系统负载压力影响的显著性及先后顺序。该研究为建立甘蔗收获机械切割系统的负载压力与切刀入土切割深度的关系数据库提供了数据支持。     

贵州省农机专业合作社现状及发展建议

近年来,随着《中华人民共和国农民专业合作社法》的颁布和农机购置补贴力度的不断加大,贵州省农机专业合作社得到了较快发展。现有的农机专业合作社较好地解决了农机规模化作业与小农户分散经营的矛盾,有利于资源的合理配置和减轻农户劳动强度,解放了大量的农村劳动力,有效地增加了农民的收入。为此,通过对贵州省农机专业合作社的基本情况、发展特点、在农业生产中所发挥的作用及存在的问题等方面进行了较为广泛与深入的阐述,提出贵州省农机专业合作社建设中的若干建议,供相关部门参考。     

小麦的叶面积、穗粒重和谷叶比的基因效应

用两个小麦杂交组合的 P₁、P₂、F₁、F₂、B₁、B₂和 F₃7个世代,用世代均数分析研究了小麦的剑叶面积,第二叶及第三叶面积,单穗粒重和谷叶比的遗传,用加权最小二乘法估算了遗传参数。结果表明,加性效应表现了极为显著的作用,显性效应也是显著的,     

基于基因表达式编程的作物水分生产函数构建

作物水分生产函数的确定是农业水资源优化配置的关键。该研究采用农业水文生态系统模型（Agro-Hydrological & Chemical and Crop systems simulator, AHC）与基因表达式编程（Gene Expression Programming, GEP）相结合的方法构建作物水分生产函数。以河套灌区3种主要作物（葵花、玉米、小麦）为研究对象,采用AHC模型模拟作物产量等,构建基于GEP算法的作物水分生产函数,探讨考虑盐分胁迫的作物水分生产函数构建的思路与方法。结果表明：1）作物模拟产量与地下水埋深、地下水矿化度和灌水量等因素有关。2）构建作物水分生产函数的最优输入因子组合为地下水埋深、灌溉量、蒸散发、地下水矿化度、土壤根层盐分对作物胁迫因子、土壤根层含水率。3）应用作物水分生产函数估算不同灌溉定额条件下作物产量（预测产量）,并与AHC模型计算的产量（模拟产量）进行比较,玉米、葵花、小麦预测产量与模拟产量具有很好一致性,其决定系数分别是0.96、0.93、0.96,平均相对误差均小于5%,满足计算精度要求。因此,该研究所构建的作物水分生产函数可以较准确地估算盐分胁迫下作物产量,为农业节水与灌溉水高效利用提供科学参考。     

贵州省开阳茶园土壤养分状况与肥力质量评价

为明确贵州省开阳县茶园土壤养分状况,为优质茶叶生产提供参考,对贵州省开阳县茶园土壤进行了调查,分析了158个土壤样品的养分含量及养分间的相关性,并采用主成分分析法和模糊数学隶属度函数模型,通过计算土壤肥力综合指标值(IFI)对土壤养分状况进行综合评价。结果表明:贵州省开阳茶园土壤p H偏酸,有机质、全氮和碱解氮含量较为丰富;但全磷、速效磷、全钾和速效钾含量缺乏所占比例较大,分别仅有16.46%、14.56%、20.89%和12.66%的土壤样品达到优质高产茶园标准。开阳茶园土壤IFI值平均为0.59,属于中等以上土壤肥力茶园所占的比例为61.40%,茶园土壤肥力质量总体水平属于良好,但土壤偏酸,速效磷和速效钾的含量相对偏低,应重点改酸和增施磷钾肥。     

Anaerobic Dechlorination of Tetrachlorobisphenol A in River Sediment and Associated Changes in Bacterial Communities

Tetrachlorobisphenol A (TCBPA) is a widely used flame retardant and a potential endocrine disruptor. We estimated the role of the microbial community in degradation of TCBPA in river sediment from the vicinity of an E-waste processing facility. The effects of different anaerobic conditions on degradation efficiency of TCBPA were investigated, and differences in bacterial communities among these conditions were analyzed by 16S ribosomal RNA (rRNA) gene sequencing. The most effective dechlorination of TCBPA occurred under methanogenic conditions followed by electron donor-enhanced conditions and sulfate-reducing conditions with initial sulfate concentrations of 1, 10, and 20 mM. The extent of TCBPA removal under these conditions mentioned above was 65, 44, 43, 23, and 23%, respectively. 16S rRNA gene sequence analysis indicated that five dominant genera in the phylum Chloroflexi and another five species of Bacteroidetes, Chlorobi, and Firmicutes in these five systems were largely involved in TCBPA dechlorination. The initial sample had a total relative abundance of autochtonous potential dechlorinating bacteria of 12%. After 160 days, these values increased to 29–43% under above conditions. Addition of TCBPA decreased bacterial diversity. Efficiency of TCBPA degradation depends on the abundance and metabolism of dechlorinating bacterial guilds. The effectiveness of dechlorinating microbes in degradation of TCBPA was reduced by high sulfate concentrations.     

Impact of a Variable Tungsten Pollution on the Elemental Uptake of Two Plant Species

A radish and a grass species were grown in identical substrates either unpolluted or polluted by tungsten (W) at 1, 5, and 10 μg/g levels of watering solutions during 1 month under controlled laboratory conditions. Initially, at 4.1 μg/g, the W content in grass leaves reached 16 μg/g at the highest rate of W supply to the substrate. For radish, the content of W reached 22 and 29 μg/g in the leaves and roots, respectively. The overall W pollution increased significantly the mobility of major elements from substrate to grass leaves, especially at the 5 μg/g pollution level, whereas the W impact on radish leaves resulted in an increase of most contents, only Mn remaining unaffected. The roots from polluted radishes were enriched in Si by 21% and Al by 42% at low pollution, and in Si by 15% at high supply, whereas the uptake of the other elements remained unchanged. It looks like the W pollution at the levels chosen does not impact the transfer of the major and trace elements from roots to leaves of Raphanus sativus. Alternatively, metallic trace elements (Ba, Ni, Cr, Zn, W, Co) of the Raphanus sativus and Chloris gayana leaves outline similar content changes depending on the amount of W pollution. The total rare-earth element contents of the leaves of Raphanus sativus grown in the polluted substrates are lower than those of the leaves from unpolluted substrate. Their normalization in the leaves and roots of Raphanus sativus from the polluted substrates to those of the radish from non-polluted substrate provides flat patterns for both with a positive Eu anomaly for leaves, as for those of the grass and a negative Gd anomaly for roots. Also, addition of soluble W to the substrates induced an increase in the bacterial activity of the soil.     

秦巴山区土地利用时空格局及地形梯度效应

自然景观的垂直地带性为区域土地利用的垂直景观格局奠定了基础,同时也决定了垂直景观带上土地利用的强度及其变化情况。该文采用地形位指数、分布指数、土地利用程度综合指数和土地利用信息图谱法等,分析了1989-2010年秦巴山区土地利用格局的地形梯度效应和图谱信息,揭示地形控制下土地利用时空格局和土地转移的变化规律。结果表明:1)秦巴山区土地利用以林地和耕地为主,呈西林东耕分布;1989-2010年间林地减少显著,建设用地增加明显,其中耕地是建设用地主要转入来源,林、草地是耕地主要转入来源。2)秦巴山区各生态亚区用地类型差异明显,各生态亚区土地利用转移方向也存在差异性。3)秦巴山区土地利用强度指数呈东高西低,中高周低的态势;土地利用强度变化率稳定少动,增加趋势不明显;土地利用动态度呈中高周低的态势,整体变化不大。4)水域、建设用地和耕地主要集中在地形起伏度小和坡度小的低地形位,且耕地主要转移为其他两种用地类型,建设用地有向中低地形位分布的趋势。林地和草地集中在地形起伏大、坡度陡的中高地形位,且存在着相互转移演替现象,中低地形位往往是耕地、林地、草地间的相互转换,未来势必加强坡耕地和低山丘陵区林草地的管治工作。     

改进WHCNS模型模拟耕作方式对作物生长和水分利用效率的影响

耕作改变了土壤物理特性,进而影响了作物生长和水分利用,定量研究不同耕作方式下的农田土壤水分动态与作物生长过程是制定合理耕作制度的基础。该研究在土壤水热碳氮模拟模型（Soil Water Heat Carbon Nitrogen Simulator,WHCNS）的基础上耦合了EPIC（Erosion-Productivity Impact Calculator）模型的土壤耕作模块,构建了适用于不同耕作方式的土壤水热碳氮过程模拟模型。利用华北平原南部河南商丘试验站2015-2017年实测的不同耕作方式下（深耕、免耕和轮耕）的土体储水量、叶面积指数、地上部干物质质量和产量数据对改进后的WHCNS模型进行了校验和模拟效果评价,并模拟分析了不同耕作方式对冬小麦和夏玉米农田蒸散量、作物产量和水分利用效率的影响。结果表明,所有处理的土体储水量、叶面积指数和地上部干物质质量模拟值与实测值的相对均方根误差均小于30%,一致性指数均大于等于0.90,纳什系数均大于等于0.58,决定系数均大于等于0.90,作物产量模拟值与实测值的决定系数达到0.99。与深耕和免耕相比,轮耕的两季冬小麦蒸散量分别降低了8.8%～10.8%和13.8%～21.0%,水分利用效率分别提高了6.7%～9.4%和15.7%～24.9%。与深耕和轮耕相比,免耕的两季夏玉米蒸散量分别降低了12.5%～12.9%和20.7%～22.2%,水分利用效率分别提高了13.4%～15.2%和29.1%～31.3%。耕作方式对产量的影响并不明显。总体而言,改进后的WHCNS模型可以较好地模拟华北平原不同耕作方式下土壤水分与作物生长的动态过程。