Linking watershed and microhabitat characteristics: effects on production of Atlantic salmonids (Salmo salar and Salmo trutta)

The spatial scale of environmental factors influencing population dynamics ranges from microhabitat to continental or even global scales. Integration of multiple spatial scales is important in order to understand links between environmental variation and population processes. In the present study, we investigate how multiscale drivers influence the production of stream‐rearing Atlantic salmonids (Atlantic salmon, Salmo salar L. and brown trout, Salmo trutta L.) measured in terms of abundance. Variation in juvenile production was studied using data from single‐pass electrofishing surveys (measured as biomass per m²) from nine rivers. These data were combined with habitat data ranging from an important in‐stream microhabitat variable (shelter availability) to properties of the catchment. Variation in productivity within and among rivers was affected by both properties of in‐stream habitat and catchment properties. Shelter availability and the proportion of the catchment consisting of cultivated land and lakes influenced biomass positively, while catchment area had the opposite effect. For a different set of rivers (N = 20), river gradient and catchment area were shown to positively affect the amount of shelter. Finally, the variables identified in the two preceding analysis were included in the analysis of population productivity using catch statistics from 160 rivers. The proportion of cultivated land and lakes, estimated shelter availability were found to have positive effects. In addition, temperature had a positive effect, while river width had a negative effect. This study shows that combining multiple‐scale environmental factors can explain a substantial proportion of variation in population productivity among and within the populations of Atlantic salmonids.     

Potential application of baited remote underwater video to survey abundance of west coast rock lobster Jasus lalandii

The first assessment of the baited remote underwater video system (BRUVs) for monitoring rock lobster Jasus lalandii (Milne‐Edwards) in South Africa was compared to annual ring net and trap survey data. Count data from 58 BRUVs, 36 ring net and 95 trap samples were fitted with generalised additive models using depth, habitat, time and spatial gradient as independent variables. A power analysis was used to determine the number of samples needed per annum to detect a 5 and 10% increase and decrease in population size. The BRUVs outperformed the nets and traps in terms of sampling effort and were better at detecting changes in abundance of lobster than abundance of three fish species. Considering factors such as cost, analysis time, additional data and environmental impact, traps are the most feasible method in deeper waters but BRUVs could replace nets and traps in depths less than 60 m, low‐density areas and marine reserves.     

槟榔科学研究近况分析

概述世界槟榔种植区域分布、面积和产量，及2015年度国内外在槟榔生理生化、生防菌、栽培管理、加工和利用等方面取得的研究进展，并对目前槟榔研究技术瓶颈和发展趋势进行了分析。     

Effects of biodegradable mulch on soil quality

Biodegradable plastic films are desirable alternatives to traditional black polyethylene plastic for use as mulches in agroecosystems. Efforts are ongoing to engineer biodegradable plastic mulches that could be incorporated into the soil at the end of the crop season, and decomposed by microorganisms, ultimately to CO₂, H₂O, and biomass. Whether changes in soil quality occur during or following biodegradation is unknown. An 18-month study evaluated the effects on soil quality following burial of four potentially biodegradable mulches and a no mulch control in high tunnel and open field tomato production systems across three geographically distinct locations (Knoxville, TN; Lubbock, TX; Mount Vernon, WA). The mulch treatments included: two starch-based mulches (BioAgri^® Ag-Film and BioTelo Agri); one experimental 100% polylactic acid mulch (Spunbond-PLA-10); one cellulose-based mulch (WeedGuardPlus; positive control); and a negative control (no mulch). The soil management assessment framework (SMAF) was used to calculate a soil quality index (SQI) according to five dynamic soil properties: microbial biomass carbon, β-glucosidase, electrical conductivity, total organic carbon (TOC), and pH. Within the 18-month evaluation period, the effects of the biodegradable mulches on the SQI were minor, and dependent upon production system and time of incubation at all locations. In general, the SQI was higher in the high tunnel systems for some of the mulch treatments at Knoxville and Lubbock but the opposite was true at Mount Vernon. By the final sampling at 18 months, the SQI was lowest for WeedGuardPlus at Lubbock and Mount Vernon but at Knoxville, the WeedGuardPlus SQI was not significantly different from the no mulch control. Of the five SMAF indicators evaluated, soil microbial biomass and β-glucosidase activity were the most responsive to mulch and production systems, supporting the use of these variables as soil quality indicators for short-term changes due to this agricultural management practice.     

高分辨率影像服务在国土资源管理中的应用

分析了国土资源管理对高分辨率影像的迫切需求，探讨了高分辨率影像处理和分析及应用环节从数据到服务的发展趋势，设计并实现了高分辨率影像服务，并以泰州市国土资源管理为例，验证了影像服务的可行性，最后，展望了高分辨率遥感影像服务的应用前景。     

Evaluation of two organosilicone adjuvants at reduced foliar spray volumes in South African citrus orchards of different canopy densities

van Zyl, J.G., Sieverding, E.G., Viljoen, D.J., Fourie, P.H., 2014. Evaluation of two organosilicone adjuvants at reduced foliar spray volumes in South African citrus orchards of different canopy densities Crop Protection 00:0000–0000.Citrus producers in South Africa generally use high spray volumes (6000 to 16,000 l ha⁻¹) to control pests and diseases adequately for the fresh fruit market. In order to study the benefit of organosilicone adjuvants at reduced spray volumes, trials were conducted with two organo tri-siloxane adjuvants. Two separate spray trials were conducted in the Western and Eastern Cape provinces of South Africa in uniform navel orange orchards. Break-Thru S240 (super-spreader) and Break-Thru Union (spreader-sticker), at recommended dosages per hectare (300 ml ha⁻¹, respectively), were sprayed separately in combination with a yellow fluorescent pigment (1 ml l⁻¹) at a high (20 l tree⁻¹ ≈ 9600 to 12,100 l ha⁻¹, depending on tree and inter-row spacing), medium (14 l tree⁻¹ ≈ 6500 to 8500 l ha⁻¹) and low (8 l tree⁻¹ ≈ 3700 to 4800 l ha⁻¹) spray application volumes. Sprays consisting of the fluorescent pigment in water alone were used as control treatments. Trees were sprayed from both sides with a commercial multi-fan tower sprayer (BSF-Multiwing) at a constant tractor speed (2.4 km h⁻¹) and spray pressure (1500 kPa). The different spray volumes were achieved by using different spray nozzles (TeeJet Disc-Core type; full and hollow cone nozzles D3-DC56/46, D4-DC56/46, D5-DC56/46). Leaves were sampled from six canopy positions (inner and outer canopy position at bottom, middle and top of the tree). Deposition quantity and quality of fluorescent pigment were determined on upper and lower leaf surfaces using fluorometry, digital photomacrography and image analyses. Spray uniformity and efficiency were also compared among treatments. Deposition quantity generally increased with increasing spray volume, but normalised values showed better spray efficiency at lower volumes. In pruned and less dense canopies, a beneficial effect of adjuvants was observed in terms of deposition quantity, efficiency and uniformity, especially at reduced volume applications (14 l tree⁻¹) on the inside and outside of the canopy. Little improvement in deposition quality was generally observed with the use of adjuvants. These benefits were not as evident in very dense canopies, illustrating the importance of canopy management when spraying at reduced volumes. Data obtained from the study is valuable for future improvement in spray application methodology in South Africa and other developing countries.     

乡镇污水处理厂运行管理相关问题探讨

乡镇污水处理厂作为环保基础设施建设的重点,普遍存在重建设轻运营的问题。笔者结合重庆市实际情况,重点分析了乡镇污水处理厂运行管理中存在的问题,并有针对性地提出了建议,包括提高收集率、完善末端工艺、专业化运营、改变考核体系、优化污泥处置、加强再生利用和远程在线监控等。     

农业生产基地项目环境影响评价要点分析及探讨

农业生产基地项目具有影响范围大、产品服务多元化等特点，涉及行业类别较多，其环境影响评价文件也相对复杂。环境影响评价报告编制单位应充分与建设方进行沟通，熟悉项目建设内容，挖掘项目可能的产生污染的环节和设施，明确环境影响范围和环境敏感点，并对项目损益进行两方面的分析。     

生态公益林管护存在的问题及对策

通过查阅生态公益林的相关文献,总结了生态公益林在宏观和微观方面管理存在的问题,并从健全体系、普及知识、补偿机制等方面提出了加强生态公益林管护对策。     

农业科研单位外事管理工作的思考——以丹东农业科学院为例

外事管理工作对于农业科研单位而言,既是加强国际交流与合作的桥梁,又是吸收国外先进农业技术、管理经验的重要渠道之一。文章阐述了丹东农业科学院外事管理工作取得的成效,分析了农业科研单位外事管理工作存在的问题,并针对问题提出了解决对策,在此基础上,进一步提出了建立并完善外事管理规章制度、积极开展多领域的对外交往活动、促进面向国际市场的科研成果转化等促进农业科研单位外事管理水平提升的建议。