Evaluating the efficiency of sampling methods in assessing soil macrofauna communities in arable systems

The soil fauna is often a neglected group in many large-scale studies of farmland biodiversity due to difficulties in extracting organisms efficiently from the soil. This study assesses the relative efficiency of the simple and cheap sampling method of handsorting against Berlese–Tullgren funnel and Winkler apparatus extraction. Soil cores were taken from grassy arable field margins and wheat fields in Cambridgeshire, UK, and the efficiencies of the three methods in assessing the abundances and species densities of soil macroinvertebrates were compared. Handsorting in most cases was as efficient at extracting the majority of the soil macrofauna as the Berlese–Tullgren funnel and Winkler bag methods, although it underestimated the species densities of the woodlice and adult beetles. There were no obvious biases among the three methods for the particular vegetation types sampled and no significant differences in the size distributions of the earthworms and beetles. Proportionally fewer damaged earthworms were recorded in larger (25 × 25 cm) soil cores when compared with smaller ones (15 × 15 cm). Handsorting has many benefits, including targeted extraction, minimum disturbance to the habitat and shorter sampling periods and may be the most appropriate method for studies of farmland biodiversity when a high number of soil cores need to be sampled.     

成都市数字农业农村标准化建设现状及对策

本文总结了成都市数字农业农村标准化建设的现状,分析了存在的问题,提出了出台标准体系、研制关键标准、增强标准意识、培养复合型人才、探索标准共建、促进标准建设等对策,以期为成都市数字农业农村标准化高质量发展提供参考。     

Modeling height-diameter relationship for artificial monoculture Metasequoia glyptostroboides in sub-tropic coastal megacity Shanghai,China

Tree height is a key variable in forest monitoring studies and for forest management. However, tree height measurement is time consuming, and the recommended procedure is to use estimates from tree height (H) - diameter at breast height (DBH) models. Increasingly, H-DBH models are being developed for urban forests, providing tools to forest management and ecosystem services estimation. Here, we compared model forms and approaches for predicting H as a function of DBH and additional stand level covariates variables. Four model forms were evaluated: (i) basic models (which only used DBH as predictor variable); (ii) generalized models (which used DBH and other predictor variables based on the best basic model); (iii) a mixed-effects model based on the best basic model; and (iv) a mixed-effects model based on the generalized model. Several sampling designs aimed at minimizing height measurement were tested in terms of accuracy and applicability. Taking predicted accuracy and investigation cost into account, we recommend generalized non-linear mixed-effects model (NLME) when there were two or less tree height measurements taken in a given stand. The basic NLME model could be calibrated when there were 3 or more tree height measurements, depending on the required level of accuracy and investigation cost. Additionally, we first reported that soil pH as a covariate variable in H-DBH model and our generalized NLME model implied that the difference in the H-DBH relationship caused by pH varies among different stands. This finding may be attributable to differing biological properties of the similar alkaline tolerance species.     

我国兽医生物制品标准体系建设工作研究与思考

分析了国家标准的概念、我国兽医生物制品标准体系的构成,介绍了我国兽医生物制品标准体系的历史和现状,指出了现阶段我国兽医生物制品标准化工作中存在问题及其原因,提出了统一认识、按照全新思路开展《兽药典》制定、加强对企业标准的备案审查、做好疫苗效果评价用强毒株的筛选、完善相关法律法规并做好与标准体系的衔接5项建议。     

计算机家具图符研究

论述了简化图符在家具设计中的作用与意义,建立了一套３８种家用图符,旨在解决家具图符没有统一标准,信息传递混乱等方面的问题,可加速ＦＣＡＤ在微机中的应用。     

稻粉虱若虫空间分布型及取样技术

应用聚集度指标和Ｍ－Ｘ回归检验,得出稻粉虱若虫空间分布型为聚集分布型,以５种取样方法与对照相比较,差异均不显著;但以棋盘式、平行线取样接近对照,且平行线取样方便易行,可采用。抽样量ｎ＝６２．９６８４Ｘ＋２０．０２７０,序贯抽样模式为Ｔ０（Ｎ）＝２５Ｎ±５８．０１１７Ｎ。     

推广玉米收获机械化需要注意的关键问题

玉米收获机械化一直是制约黑山县玉米全程机械化的瓶颈,但推广玉米收获机械化需要具备一定的条件。推广玉米收获机械化需要注意的关键问题是需要适度规模经营和规范播种,并与当地实际相结合。同时,玉米收获机产品应采用标准化．提升产品质量和服务质量,为大面积推广玉米收获机提供条件。     

The future of fish passage science,engineering, and practice

Much effort has been devoted to developing, constructing and refining fish passage facilities to enable target species to pass barriers on fluvial systems, and yet, fishway science, engineering and practice remain imperfect. In this review, 17 experts from different fish passage research fields (i.e., biology, ecology, physiology, ecohydraulics, engineering) and from different continents (i.e., North and South America, Europe, Africa, Australia) identified knowledge gaps and provided a roadmap for research priorities and technical developments. Once dominated by an engineering‐focused approach, fishway science today involves a wide range of disciplines from fish behaviour to socioeconomics to complex modelling of passage prioritization options in river networks. River barrier impacts on fish migration and dispersal are currently better understood than historically, but basic ecological knowledge underpinning the need for effective fish passage in many regions of the world, including in biodiversity hotspots (e.g., equatorial Africa, South‐East Asia), remains largely unknown. Designing efficient fishways, with minimal passage delay and post‐passage impacts, requires adaptive management and continued innovation. While the use of fishways in river restoration demands a transition towards fish passage at the community scale, advances in selective fishways are also needed to manage invasive fish colonization. Because of the erroneous view in some literature and communities of practice that fish passage is largely a proven technology, improved international collaboration, information sharing, method standardization and multidisciplinary training are needed. Further development of regional expertise is needed in South America, Asia and Africa where hydropower dams are currently being planned and constructed.     

取样时间和消毒方法对青钱柳茎段腋芽诱导的影响

[目的]解决青钱柳组织培养过程中外植体污染问题。[方法]以青钱柳带腋芽的茎段为材料,研究不同取样时间和消毒方法对青钱柳茎段腋芽萌发率的影响。[结果]最佳采样时间为4、5月,最优消毒处理分别为70%乙醇30 s+0.10%升汞12 min(4月)和70%乙醇30 s+0.05%升汞16 min(5月)。[结论]试验结果为建立青钱柳的无性快繁体系奠定了基础。     

新型根系分泌物采样装置的介绍与应用

根系分泌物在土壤-植物养分循环和缓解植物环境胁迫方面具有重要作用。根系分泌物的收集是研究植物根系过程和相应机制的基础。通常所用的溶液收集法简单易操作,但由于人为扰动大,不能反应根系分泌物的真实情况。介绍了一种新型根系分泌物原位连续采样装置,该装置由根系生长箱和根系分泌物收集装置二部分组成。根系生长箱中土壤和根系之间由滤膜隔开,土壤中的营养元素可以透过滤膜供应植物生长,带有真空抽气泵的根系分泌物收集装置可以实现用去离子水原位淋洗根系、收集根系分泌物的目的。该收集装置外源葡萄糖加标回收率为89%±2%。小麦种植在根系生长箱中,在小麦生长42 d期间,用新型采样装置和溶液收集法分别收集了根系分泌物,研究了小麦根系分泌DOC能力随生长时间的变化。结果表明,收集方法不同,小麦根系分泌DOC能力随生长时间变化不同。在新型收集装置法中,小麦根系分泌DOC能力随着生长时间呈现降低的态势,而溶液收集法则呈现出上升的态势。新型采样装置能实现植物土壤生长条件下原位收集根系分泌物,采样中扰动小,为根系分泌物研究提供了较好的收集方法。但也存在设备复杂、采样流量不易控制等缺点,是今后需要改进的方向。