“一带一路”背景下陕西茶叶跨境电商发展路径研究

陕西作为丝绸之路的发源地，以其有利的自然生态条件和区域产业结构，形成了以茶叶为主导的产业发展格局。目前，陕西省茶叶出口规模不大，市场占有率较低。在“一带一路”倡议的推动下，陕西省茶叶出口至沿线国家的潜力较大，未来将逐步呈上升态势。研究了“一带一路”背景下陕西茶叶跨境电商市场发展现状和存在的问题，提出陕西茶叶跨境电商发展路径，通过借力跨境电商平台、开拓国际市场、稳固绿茶品牌、布局海外仓解决出口难的问题，以及完善跨境电商法律秩序，拓展陕西茶叶跨境电商发展路径。      

不同起垄方式对植烟土壤物理特性及烤后烟叶产质量的影响

为了探讨起垄方式与移栽方式对河南省周口市烟区植烟土壤物理特性和烤后烟叶产质量的影响,以筛选适合周口烟区烤烟产质量和土壤物理特性同步提高的起垄与移栽处理组合模式。采用田间试验法,以‘中烟100’为研究材料,依据起垄方式与移栽方式设置龟背型膜上移栽(T1)、龟背型膜下移栽(T2)、中凹型膜下移栽(T3)和中凹型膜上移栽(T4)4个试验处理,研究不同起垄方式对土壤物理特性和烤后烟叶产质量的影响。结果显示,中凹型起垄的单独和复合处理均可以有效地改善土壤的物理特性和提高烟叶的产质量,其中以中凹型起垄配合膜下移栽处理(T3)效果最好。与T1相比,T3处理可以显著提高各土层土壤含水率和总孔隙度,降低土壤容重,明显促进烤后烟叶中化学成分更加协调,上部叶中性致香物质含量较T1提高了15.96%,产量和产值较T1处理显著提高。因此,中凹型起垄膜下移栽处理更有利于改善植烟土壤物理特性和提高烤后烟叶产质量,是最佳种植模式,结果为河南省周口烟区适宜的烟草种植模式提供理论依据。     

基于距离相关系数和KNN回归模型的森林蓄积量估测研究

【目的】探究Landsat8 OLI数据和KNN算法在森林蓄积量估测中的潜力。【方法】以湖南省湘潭县为研究区,采用Landsat8 OLI数据和同时期的二类调查数据,通过距离相关系数筛选特征,分别采用线性回归模型(MLR)、K-近邻模型(KNN)、距离加权KNN模型(DW-KNN)和优化欧式KNN模型(FW-KNN)对森林蓄积量进行估测。使用十折交叉方法进行精度检验,对检验结果进行对比分析。【结果】3种KNN模型的估测结果均高于传统的线性模型,并且在3种KNN模型中,FW-KNN算法效果最好,决定系数达到0.69,为3种模型中最高;3种KNN模型中,本研究优化欧氏距离KNN模型的估测精度最高,其均方根误差为30.3%,相比于传统KNN模型的均方根误差降低了5.1%,相比于DW-KNN模型降低了3.3%。【结论】采用DW-KNN蓄积量估测结果明显优于其他两种模型,说明通过特征与蓄积量的相关性优化样本间的距离是一种可行的KNN优化方法。     

红掌新品种‘明农月华’

‘明农月华’红掌是以‘森萨’为母本，‘白王子’为父本杂交选育而成的紫色盆花新品种。株形直立紧凑，生长势强，具有丛生特性。平均株高56.0 cm，冠幅46.8 cm。叶片深绿呈卵心形；佛焰苞中等卵圆形，粉紫色且富有光泽，肉穗花序直立，呈紫色，高于叶。从组培苗出瓶至形成成品约15个月，常年开花，花期持久，抗病性强，适应性好。     

四要素变量施肥机肥箱施肥量控制算法设计与试验

针对黑龙江农垦地区垄作玉米施肥过程中遇到的肥料分层问题，设计了一种四要素变量施肥控制系统。系统采用电液比例控制技术，主要由液晶显示终端、变量施肥控制器、4路液压马达和编码器、4路排肥机构（排肥轴和外槽轮）和GNSS模块组成。为了实现氮肥、磷肥、钾肥和微肥的一次性及时、准确施用，提出了一种基于复合交叉原则的各路施肥量确定策略，基于PID技术设计了液压马达控制算法。根据用户在变量施肥控制软件中设置的目标施肥量，系统自动确定各肥箱精确施肥量，基于PID液压马达控制算法，实时计算4路液压马达的目标转速，同步向控制器发送4路转速指令，一次性完成氮肥、磷肥、钾肥和微肥4种肥料的同步变量施用。为了验证各路施肥量控制算法的效果，分别进行了PID算法响应时间和精度试验、变量施肥系统单质肥排肥性能验证试验和作业条件下各肥箱施肥量控制算法验证试验。试验结果表明，基于PID技术的排肥轴转速控制算法响应时间不大于0.5s；变量施肥系统单质肥排肥性能误差绝对值不大于3%；作业条件下各路施肥量控制算法显著减少了氮素的施用量，实现了氮肥、磷肥、钾肥的精确投入。四要素变量施肥机各路施肥量控制算法完全满足了垦区玉米施肥精确、均匀施用的要求。     

Performance of common buckwheat (Fagopyrum esculentum M.) in response to row spacing under ridge and furrow cropping systems in a semiarid region of China

Ridge and furrow systems as well as the wide-narrow row spacing are recognized as good management practices in crop production. To obtain some available information concerning the suitable agricultural practices for buckwheat cultivation in arid and semi-arid area, a two-year field study was conducted to investigate the performance of common buckwheat grown under six cropping patterns: conventional flat single/double row planting (NS/ND); furrow single/double row planting (FS/FD); ridge single/double row planting (RS/RD); single row planting with equal row spacing and double row planting with wide-narrow row spacing practice. Plants grown under the FD system exhibited higher water use efficiency (WUE) and rainfall use efficiency (RUE) than plants cultivated with the NS system, increases with 13.7% and 21.9%, respectively, in 2014, while 9.8% and 14.0%, respectively, in 2015. Plants of the FD system also displayed the greatest leaf area index and canopy openness at growth stage of 40, 60, and 80 days after sowing, maximum biomass production (13.96 t ha^?1) and grain yield (3486.2 kg ha^?1) in 2014, and the least pronounced soil nitrate consumption as compared to plants from other tillage systems. We conclude that FD is the optimum planting pattern for common buckwheat cultivation in semi-arid and arid environments.     

农民专业合作社的联合路径研究——基于联合社的多案例分析

随着农民专业合作社联合社在农业现代化进程中的地位逐渐凸显,识别其联合路径对联合社的良性发展具有重要意义。基于系统理论框架,以"苏合"销售合作联社、"邓村绿茶"专业合作社联合社、黑龙江"龙联"联合社为案例,分析基于合作社服务功能系统的合作社联合路径,并探讨各联合路径的差异性和共性。结果表明,合作社之间的"二次合作"有助于激活组织间的互补和协同作用,打破原有合作社服务能力提升的禀赋约束,增加农民合作经济的效用;合作社的联合有同服务区位联合,服务系统内联合和跨服务系统联合3条联合路径;各路径之间没有优劣之分,但联合效用的充分发挥需要联合社对自身有清晰的定位,还需与成员能力相匹配,并且以完善的运营模式为保障。研究表明,不同的联合路径适用于不同规模的合作社。因此,对已具规模的合作社鼓励其结成战略联盟,对初具规模的合作社鼓励其进行同类产品的联合,对规模较小的合作社鼓励其进行专业性联合。     

Fish functional diversity responses following flood pulses in the upper Paraná River floodplain

Flood pulses are the main force driving the dynamics of aquatic communities in floodplains. The responses of communities to environmental changes following flood pulses usually demand a time lag to appear and reach the climax. We assembled a data set of 16 years of fish samplings to assess the relationship between water level and four functional diversity measures, in the upper Paraná River floodplain. Specifically, we approached four aspects of each relationship between water level and functional diversity: nature (positive or negative), sensitivity (response intensity), responsiveness (response delay) and extent (response duration). The nature of the relationship between water level and functional diversity was positive in all cases. Functional richness (FRic) responded right after flood pulses, although with shorter extent. Abundance‐dependent functional measures (evenness—FEve; divergence—FDiv; and Rao's quadratic entropy—Rao's Q) presented delayed responses, reaching peaks more than 1.5 years after flood pulses. Significant effects of floods on fish functional diversity were observed for more than 3 years, although the highest functional diversity was observed with 1.8 years, on average. More importantly, flood pulses had no longer significant effects on functional diversity after 4 years. Regarding conservation strategies in regulated systems, flood events should occur every 2 or 3 years, with adequate timing (October‐November), intensity (up to 450 cm) and duration (at least 50 uninterrupted days). Intervals longer than 3 years or inadequate timing, intensity and duration could dramatically decrease functional diversity and compromise ecosystem services.