头足类分类鉴定的研究进展

头足类作为软体动物门中的重要组成,不仅具有很高的经济价值,而且还是海洋生态系统组成中不可或缺的一部分,加大对头足类的开发利用已成为世界各国的目标之一。头足类种类繁多,通常是抹香鲸等高等动物的重要饵料,因此其分类鉴定显得尤为重要。本文从方法和材料两个方面对头足类的分类鉴定进行了系统的回顾与总结。传统的外部形态学与生态学在头足类的分类鉴定已经相当成熟,耳石是头足类信息的良好载体,可作为种类和种群划分的主要依据;角质颚是头足类的主要摄食器官,具有稳定的形态特征、良好的信息储存以及耐腐蚀等特点,不同种类之间有着显著的差别,是分类鉴定的良好材料。头足类的分类鉴定要在发挥传统分类学优势的同时,加大分子水平上的研究力度,并将二者结合,相互佐证。此外,还应加强对头足类硬组织的研究和基础资料积累,并建立完整的数据库及检索系统,使其在分类鉴定中得到更加有效的应用。     

Soil physical changes and maize growth in a structurally fragile tropical soil due to mulching and duration between irrigation intervals

Under tropical meteorological conditions, the volume of soil explored by plant roots is crucial for crop growth as it allows increased water and nutrient use efficiency. We hypothesized that, under different irrigation intervals, leguminous mulch can extend the duration between irrigation events but maintain crop performance, because decreased evaporative fluxes also reduce constraints to root exploration imposed by mechanical stress. We evaluated the combined effects of leguminous mulch and irrigation intervals on soil physical properties to determine whether the growth and productivity of maize were modified in a structurally fragile tropical soil. The experiment involved the following treatments: 4‐day irrigation intervals with soil mulched (4C) or bare (4S), 6‐day irrigation intervals with soil mulched (6C) or bare (6S), 8‐day irrigation intervals with soil mulched (8C) or bare (8S) and 10‐day irrigation intervals with soil mulched (10C) or bare (10S). Mulch decreased soil penetration resistance and increased to 4 days the favourable time for root development in drying soil. Relative to bare soil, mulch with a 6‐day irrigation interval almost doubled nitrogen uptake post‐tasselling, which decreased nitrogen remobilization and increased the crop growth rate during this stage. These conditions had a positive effect on the transpiration rate and stomatal conductance as well as on the growth and yield of maize. A 6‐day irrigation interval with mulch compared to 4 days with bare soil resulted in similar conditions for root development, but greater uptake of nitrogen (102.73–78.70 kg/ha) and better yield (6.2–5.3 t/ha), which means greater efficiency in nitrogen and water use.     

我国牧草种植成本收益变化与比较

本研究以牧草种植户牧草及粮食作物的调研数据为基础,计算出2010-2014年主要牧草和粮食作物的成本收益基本信息,对其变化进行统计分析,并对各作物的成本收益进行比较。分析发现,2014年苜蓿(Medicago sativa)的经济效益有所下降;黑麦草(Lolium perenne)和青贮玉米(Zea mays)的纯收益和收益率有所增长;苜蓿的纯收益和收益率要高于黑麦草和青贮玉米;马铃薯(Solanum tuberosum)和苜蓿的经济效益更具优势,种植小麦(Triticum aestivum)经济效益较差;黑麦草和青贮玉米人工和土地成本更高,苜蓿水电费最高。建议调整农业产业结构,推行"粮+经+饲+草"四元种植结构,全面扶持牧草产业发展,建立健全牧草生产资料补贴制度。     

森林经理科学数据整合技术研究

分析了目前森林资源各类数据存在的问题。针对问题,从森林经理科学数据整合范畴、森林经理科学数据分类与编码、森林经理科学元数据存储与采集等方面进行研究。研建了森林经理科学数据分类体系和编码方法;设计了相应的数据库、元数据字典和代码库;采用VBA技术开发了元数据采集工具。以热带林业实验中心森林经理科学数据管理应用为案例,初步实现了森林经理科学数据整合方法的探索性研究。应用结果表明:通过科学数据整合能有效地改进数据的质量,使分散在各部分的数据便于规范管理、便于开展多目标、多学科和多行业应用,为以后进一步数据挖掘奠定了基础。     

Crop and cattle production responses to tillage and cover crop management in an integrated crop–livestock system in the southeastern USA

Integrated crop–livestock systems can help achieve greater environmental quality from disparate crop and livestock systems by recycling nutrients and taking advantage of synergies between systems. We investigated crop and animal production responses in integrated crop–livestock systems with two types of winter cover cropping (legume-derived N and inorganic fertilizer N), two types of tillage [conventional disk (CT) and no tillage (NT)], and whether cover crops were grazed by cow/calf pairs or not. The 13-ha field study was a modification of a previous factorial experiment with four replications on Ultisols in Georgia, USA. Recurring summer drought severely limited corn and soybean production during all three years. Type of cover crop had little influence and grazing of cover crops had minor influence on crop production characteristics. Cattle gain from grazing of winter cover crops added a stable component to production. No-tillage management had large positive effects on corn grain (95 vs. 252 g m⁻² under CT and NT, respectively) and stover (305 vs. 385 g m⁻²) production, as well as on soybean grain (147 vs. 219 g m⁻²) and stover (253 vs. 375 g m⁻²) production, but little overall effect on winter wheat grain (292 g m⁻²) and stover (401 g m⁻²) production. Our results suggest that robust, diversified crop–livestock systems can be developed for impoverished soils of the southeastern USA, especially when managed under no tillage to control environmental quality and improve resistance of crops to drought.     

A trait-based characterization of cover plants to assess their potential to provide a set of ecological services in banana cropping systems

Cover plants are one of the means to increase the functional biodiversity of fields and to enhance the ecological functions of the communities. However, the design of cropping systems including cover plants relies largely on expert knowledge. There is a lack of methods to select the best suited cover plants according to their role in the agrosystem. We propose to use functional traits to select cover plants suited to sustain ecological services in the banana agrosystems of the French West Indies. Our objectives were (i) to characterize a collection of cover plants on a trait basis, according to their potential to provide the services expected in a banana agrosystem and (ii) to discuss the potential use of this characterization for the design of innovative multi-species banana cropping systems. In these systems, four main services are targeted, i.e. controlling weeds, controlling plant-parasitic nematodes, improving soil fertility and particularly N availability, and avoiding competition with banana for resource acquisition. Three experiments were conducted, under field and controlled conditions, to evaluate the potential of a collection of 28 tropical cover plants to achieve the functions related to these services. For each cover plant, a functional profile was constructed from a combination of plant traits that are easy to assess experimentally. It described plants’ potential to achieve the functions expected in a banana agrosystem. Functional profiles required for cover plant usages were also identified. The comparison of the plant functional profiles and the functional profiles required for their usages enabled us to select the best suited plants for each usage. However, these functional profiles rarely corresponded, meaning that a cover plant is rarely sufficient to achieve all the functions required for a usage. Functional complementarities obtained by the mixture of different species of cover plants are thus often required. Compared to classical approaches of innovative cropping system design based on the experimental testing of spatial and temporal plant combinations, such a trait-based approach saves time by focusing on a shortlist of cover plants best suited according to their functions in the agrosystem.     

Optimisation of fertiliser rates in crop production against energy use indicators

Optimising mineral nitrogen (N) use in crop production is inevitable target as mineral fertilisers reflect one of the highest inputs both in terms of economy and energy. The aim of the study was to compare the relationship between the rate of N fertiliser application and different measures of energy parameters exemplary data for spring-wheat in boreal climate condition in Estonia in 2006–2010. The effect of mineral N with rates 0, 40, 80, 120 and 160 kg N ha⁻¹ was studied on the background of composted cow manure and without organic fertilisers. Univalent parameters, energy gain (EG) (energy output − energy input) and energy ratio (ER) (energy output/energy input) were calculated. To aggregate parameters with different units (ER and EG) we proposed two standardisation approaches for combined indices. ER maximisation gave both organic fertilisation background optimum N norms significantly lower than EG (p < 0.05) optimisation. Both the new combined indices gave optimum N norms in between the rate of ER an EG. Composted cow manure background did not affect mineral N optimisation significantly. We suggest optimisation of mineral N according to bi-dimensional parameters as they capture important features of production efficiency and are more objective using as advisory tool for sustainable production systems.     

基于GF-1影像面向对象分类方法的水稻种植信息提取研究

应用遥感技术提取水稻种植信息是农业遥感的重要内容。GF-1卫星WFV数据为农业信息提取提供了新的途径,面向对象的分类方法是遥感解译的重要方法。本研究以扬州市为研究区域,基于GF-1影像WFV数据,采用面向对象的分类方法,提取水稻种植信息,并实地调查验证试验结果,试图探讨GF-1数据面向对象分类方法在水稻种植信息提取中的可行性与影响提取精度的因素。结果表明,应用GF-1数据,采用面向对象的分类方法能够很好地完成扬州市水稻种植信息的提取,2016年扬州市有水稻种植面积214 524 hm~2,总体精度达到98.5%,Kappa系数0.95,面积精度达97.5%;实地考察能够提高提取精度,地形破碎程度越低,提取精度越高。     

黄河三角洲河道演变与景观格局分析

以黄河三角洲地区东营市部分为研究区域,研究了黄河三角洲河道演变规律与景观格局分布规律,并着重研究了该地区河道演变与景观格局分布的联系。结果表明:近20年间黄河总取水量呈上升趋势;2002~2010年裸地沼泽面积明显减少,植被面积增多。2010~2019年,建设用地面积明显增加;土地利用景观格局的形式从沿海区域开始向内陆演变呈现一定的规律,最外环为海洋、向内依次为是浅海滩涂、滩涂、水产湿地、盐田、旱地、沼泽湿地、植被、建设用地;受季节影响较大的图可以利用ENVI提取其对应的植被覆盖图来消除影响。在NDVI植被归一化指数的基础之上建立植被覆盖图,通过NDVI指数分析植被的长势和营养状况。