Litter Productivity and Nutrient Return Characteristics of Three Typical Forest Stands in Golden Mountain

Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm-2;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm-2 and 2.3 - 5.71 kg·hm-2 respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.

Content Determination of Total Flavonoids in Tetracera asiatica from 10 Different Production Areas in Guangxi

[Objectives] To determine the content of total flavonoids in Tetracera asiatica from different production areas in Guangxi and provide a basis for improving the quality standards of crude drug. [Methods] Using 50% ethanol as extractor,NaNO_2-Al(NO_3)_3-NaOH as chromogenic system and rutin as the reference substance,the content of total flavonoids from the crude drug was determined. [Results] A method for determining the content of total flavonoids was established,the content of total flavonoids was 11.35-21.35 mg·g^(-1),and the average content was 17.64 mg·g^(-1). [Conclusions] The method had high repeatability and stability,and the method was simple,rapid and sensitive and suitable for quantitative analysis.

Change and control of nitrogen in molten steel production process

The change and control of nitrogen content in molten steel was investigated through the production process of "LDBAr-LF-RH-CC". Results show that nitrogen content reduces gradually in converter-steelmaking stage, rises rapidly from the end of converter process to the end of argon station process, continues to increase in ladle furnace process, and decreases slightly in RH refining stage. Since nitrogen is removed mainly by BOF steelmaking and vacuum refining operations, nitrogen in molten steel should be removed as much as possible in these two operations. However, nitrogen uptake should be minimized in other operations of molten steel production process.

Preliminary Study on the Standard of Selenium Content in Agricultural Products

With the improvement of living standards, people pay more attention to the agricultural products with health protection function, and the selenium-rich agricultural products attract more and more consumers. The main biological role of selenium is to resist oxidation and inflammatory response, mainly focusing on resisting aging, preventing cardiovascular disease, protecting eyesight, counteracting or destroying the toxic properties, preventing cancer and thyroid disease. In most areas of China, there is a widespread shortage of selenium, thus producing selenium-rich agricultural products to provide natural selenium-rich health food to the areas in need of selenium, has gradually become a new hot spot of China's health food industry, but high content of selenium in food is detrimental to human body, even leads to selenium intoxication, and artificially adding inorganic selenium is difficult to guarantee that the selenium content of agricultural products is not exceeded. According to human body's daily demand for selenium in dietetics and the content of selenium in agricultural products in the Chinese food composition table, we put forward the recommendations on the standard of selenium in agricultural products, in order to provide the basis for China to formulate the health standard of selenium content in selenium-rich agricultural products.

Effect and Analysis of Mechanized Production on Ratooning Ability of Guitang 47

[Objectives] This study was conducted to explore the effect of machine harvesting on ratooning ability of Guitang 47, and to provide basis for mechanized production of Guitang 47. [Methods] On the basis of mechanized planting and management of newly planted sugarcane Guitang 47, a comparative test of machine harvesting and manual harvesting was conducted, during which the plant generation rate, sugarcane yield, sucrose content and related agronomic traits of ratoon cane were continuously investigated in two years after machine harvesting of the newly planted sugarcane. [Results] There were no significant differences in the plant generation rate, plant height, stalk diameter, millable cane, sugarcane yield and sucrose content from manual harvesting of Guitang 47 in the first and second years after machine harvesting. In the second year after machine harvesting, the yields of ratoon cane and the sugar content reached 101.70 and 15.32 t/hm^2, respectively, which were equivalent to those of manual harvesting. [Conclusions] Guitang 47 has strong ratooning ability and lodging resistance and strong resistance to rolling and crushing, and is adaptive to full mechanized production. It should be promoted and accelerated in sugarcane areas lacking labor to reduce costs and increase benefits.

Cultivation Systems Using Vegetation Cover Improves Sustainable Production and Nutritional Quality of New Rice for Africa in the Tropics

Little is known about the impact of direct sowing under vegetation cover on the production and quality of New Rice for Africa （NERICA） on poor oxisol. In this study, two NERICA varieties （NERICA 3 and NERICA 8） were grown under tropical oxisol soil with very low nutrient contents. Four cultivation systems were used in completely randomized block design, including plowing （control）, unplowed soil with dead vegetation cover （DVC）, unplowed soil with live vegetation cover （LVC） and unplowed soil with mixed vegetation cover （MVC）. DVC significantly improved the exponential growth of NERICAs. NERICA 3 was the more productive （2.16–3.05 t/hm2） compared with NERICA 8 （0.71–1.21 t/hm2）. Cultivation systems improved the nutritional quality of NERICAs. The total protein content of NERICA 3 under DVC and MVC was 84.8% and 75.0% higher than control, respectively. The total soluble carbohydrate contents of NERICA 8 under LVC and MVC was 73.2% and 57.3% higher than control, respectively. These results suggested that conservative approach like direct sowing on unplowed soil with vegetation cover systems can improve the nutritional quality of rainfed NERICAs and their sustainable production under poor oxisol soil in sub-Saharan Africa.

Chemical Analysis Method for Carbon Bearing Refractory Products——Determination of Magnesium Oxide Content by CyDTA Volumetric Method

This standard specifies the method summary, reagents, apparatus, sampling, procedure, test results calculation and permissible tolerance of the determination of magnesium oxide by CyDTA volumetric method.

Methods of Maintaining Steady oil Production In Late High－Water－Cut Stagein Daqing Oilfields

By the end of 1990,Daqing,Oilfields had been produ-cing for 30 years with water flooding.The composite water cut was as high as 79%.In the general regularity of developing large scale sandstone reservoirs,the oilfields had been in their later stage of production,char-acterized by rapid decline of oil.output.It is very difficult to keep a steady oil production without any breakthrough in oilfield development techno-logies.

对水利新质生产力的理解及发展思考

水利新质生产力是新质生产力的重要组成部分,也是新质生产力的重要基础,要把水利新质生产力落实到水利工作的全过程、各方面。基于水利新质生产力的内涵、构成要件,及其与新质生产力、水利高质量发展的关系,从不同角度深入认识水利新质生产力,阐述发展水利新质生产力的重要意义。提出发展水利新质生产力的框架,包括根本宗旨、战略指导、工作理念、目标任务以及关键内容,介绍了水利新质生产力的发展思路以及需要把控的关键内容。

上海市奉贤区农田土壤-农产品中的重金属含量特征和污染评价

为分析奉贤区农田土壤和农产品的重金属污染状况,采集粮田、菜田和果园3种作物的农田土壤及其对应农产品,分别测定土壤8种重金属元素(Hg、As、Cd、Cr、Pb、Cu、Zn和Ni)和农产品5种重金属元素(Pb、Cd、Cr、As和Hg)的含量特征,采用单项污染指数法、综合污染指数法、积累指数法和富集因子等方法对土壤-农产品中重金属元素进行污染风险评价,并将地统计学与因子分析相结合分析农田土壤重金属的空间分布特征。结果表明:与上海市土壤背景值相比,奉贤区农田土壤Hg、Cd、Cr、Zn和Ni的平均含量较高,分别是背景值的1.40、1.36、1.06、1.15倍和1.44倍。单项及综合污染指数值显示土壤重金属处于无污染水平;但Cd、Ni、Hg元素的积累指数值显示无-中度污染水平,其中有4.92%农田土壤处于Hg元素的中度污染。在空间分布上,Hg呈连片分布;As、Cd整体含量低,南北区域分布;Cr、Zn呈条带状分布,自南往北递增状态;Pb呈散点状分布;Cu元素整体含量高,呈东西梯度分布;Ni元素呈岛状分布。因子分析中,因子1包括Cu和Zn,因子2是Pb,因子3包括Cd、Cr,因子4是Ni,因子5是As和因子6是Hg。奉贤地区土壤重金属含量主要受到工业源、农业源、交通源和自然源影响较大,应加强污染源控制,降低风险水平。农产品样中的5种重金属均未超出标准限量值,单项及综合污染指数值显示农产品重金属属于清洁水平。经土样和农产品样中的重金属含量相关性分析,两者无相关,农产品对土壤重金属的富集因子较小。不同土地利用方式对土壤和农产品中重金属含量影响较大,菜地土壤和农产品对Cd较为敏感,吸收能力较强,而果园土壤和农产品对各重金属吸收总体较弱。在农业生产中可以根据作物吸收重金属特性来调整种植结构,以减轻重金属污染。综合来看,奉贤区土壤-农产品系统中重金属累积程度低,但局部农田土壤中重金属含量存在轻微污染,需引起重视。

生成式人工智能赋能数字内容产业新质生产力发展:理论逻辑、动力机制及实现路径

随着数字信息科技的飞速发展,生成式人工智能成为引领生产力跃迁和产业变革的重要力量,以数字内容产业新质生产力为对象,分析生成式人工智能影响数字内容产业新质生产力发展的理论逻辑,检验生成式人工智能赋能数字内容产业新质生产力发展的动力机制,并提出实现路径。在理论逻辑方面,数字内容产业新质生产力生成的内在逻辑体现在劳动者素质、劳动资料工具、劳动对象结构的变化对数字内容创新能力、数字内容生产效率、数字内容产业质量的积极影响中,生成式人工智能赋能数字内容产业新质生产力发展的外在逻辑主要体现在能力赋能、工具赋能、内容赋能三方面。在动力机制方面,生成式人工智能以技术创新突破、要素配置优化、产业升级发展实现对数字内容产业新质生产力发展的驱动作用,系统动力学模型检验结果进一步验证了数字基础设施建设、人才要素工作效率、数字内容产业升级在生成式人工智能驱动数字内容产业新质生产力发展过程中的促进效应。在实现路径方面,从宏观数字基础设施建设、中观产业协同融合、微观人才培育及全局产业生态构建多维度层面,提出生成式人工智能驱动数字内容产业新质生产力发展的实现路径。研究结论对于推动数字内容产业高质量发展,提升产业竞争力具有较强现实意义。

生成式人工智能在期刊出版内容生产过程中的侵权责任研究

在人工智能技术快速普及的浪潮中,生成式人工智能越来越深入地参与到期刊出版内容的生产过程中。生成式人工智能通过学习和生成大量数据,具备了类似于人类创造力的能力。然而,生成式人工智能的多样性、隐蔽性、智能性导致对其不当使用会在期刊出版内容的生产过程中对著作权、名誉权等造成侵害。一方面,应对此种侵权行为的责任予以明确;另一方面,应从技术层面与法律层面加以应对。

新质生产力战略下AIGC赋能的知识和情报

[目的/意义]以人工智能生成内容为代表的AI技术赋能新质生产力涌现多维价值意蕴,可以更好地助力我国数字经济实现高质量发展,更好地助推我国知识和情报服务创新。分析AIGC赋能知识和情报创新服务的新机制、新风险和新路径,对于推动信息资源管理学科在新质生产力重大国家战略下的蓬勃发展具有重要的理论和现实意义。[方法/过程]本文依据新质生产力的理论内涵,从劳动对象、劳动者和劳动资料3个角度剖析AIGC赋能知识和情报服务创新的内在机制,依据信息传递三要素从信息源、信道和信息受体3个维度识别AIGC赋能知识和情报服务创新的风险并提出治理策略,从新质生产力构成阐释AIGC赋能知识和情报创新服务的实践路径。[结果/结论]研究表明,新质生产力战略下,AIGC以数据要素为基础,以基础模型为支撑,以人智协作为核心,形成知识和情报服务创新的内在机制;数据隐私安全风险、网络空间安全风险和科技伦理安全风险需要更好地发挥产学研协同优势进行治理;提出通过构建以数据要素驱动的新模式,组建人智协作的新团队和开发可靠可信的智能化模型促进AIGC赋能知识和情报服务创新的实践路径。

黄河流域植被总初级生产力对持续性干旱水分亏缺的响应

利用植被总初级生产力和高精度分层土壤含水量数据分析了2001—2020年黄河流域生长季总初级生产力时空分布和变化特征,量化了流域不同深度土壤湿度之间的相关关系,探究了不同植被类型在生长季的总初级生产力对土壤连续水分亏缺事件的响应关系。结果表明:黄河流域总初级生产力空间上呈东高西低、南高北低的分布特征,生长季耕地累积总初级生产力最大、林地次之、草地最小,研究期内流域总初级生产力整体呈上升趋势,耕地相对增速最大、草地次之、林地最小;流域土壤湿度在空间和时间上均有显著差异,表层土壤含水量波动对深层土壤含水量的影响随深度增加而减小,林地和耕地表层与深层土壤含水量的相关性远高于草地;流域草地和耕地总初级生产力对土壤水分的深度敏感区间为0~40 cm,林地的深度敏感区间为0~100 cm,在深度敏感区间内,随着土壤连续水分亏缺天数的增加,草地和耕地总初级生产力依次经历短暂平稳、加速下降、降速趋缓的变化过程,而林地总初级生产力则表现出短暂下挫、长时间平稳、加速下降的变化特征。

福建富硒红壤区土壤硒含量特征及作物对硒的吸收

在调查我国南方红壤区土壤及农产品中硒含量状况的基础上,分析了富硒红壤中硒的分布特征及其所产农产品中硒含量的变化规律。结果表明:我国南方富硒红壤面积较大,但在地理空间分布上具有一定破碎度;土壤中的硒虽伴生一定量的重金属和稀土等元素,但与重金属或稀土元素的相关性不大;在富硒土壤上生产的农作物总体表现为可食部位的硒含量低于非可食部位的,并且农作物中的硒含量与土壤有效态硒含量相关性显著。依据我国南方富硒红壤区土壤自身特性,可以通过调控富硒红壤区农田土壤的酸碱度、水分含量、施肥种类、施用调理剂等来提高土壤硒的有效性,达到农产品中硒含量增加的目的;同时,对外源补硒的技术和相应农产品硒的健康效应,需进一步研究与规范。

产品类型差异化影响下企业生成内容对用户参与行为的实证研究

社交媒体已成为企业营销和推广品牌、产品等不可或缺的重要渠道,企业生成内容(FGC)在其中传递信息和情感交流。基于ELM理论从聚合与独立层面审视不同产品类型企业生成内容的作用。对某企业两个官方微博的12580条微博进行文本分析,发现主流产品信息性特征内容对转发行为具有负向影响,说服性特征内容对用户参与行为具有正向影响;利基产品的信息性与说服性内容特征对转发行为具有正向影响。研究结论为企业在制定FGC发布策略以及管理FGC内容方面提供参考。

农田水利新质生产力关键内容及研究展望

水利新质生产力是符合新发展理念的先进水利生产力质态,是实现水利高质量发展的关键环节。要以水利新质生产力助力农田发展,推动农田水利新质生产力发展。农田水利新质生产力是水利新质生产力在农田领域的具体实践,是推进实现农业现代化建设和高质量发展的有力路径。为加速落实水利新质生产力在农田领域的部署要求,本文在深入探析农田水利新质生产力和水利新质生产力之间关系的基础上,构建了农田水利新质生产力的研究框架,包括关键问题、战略目标、体系布局和关键内容,并针对农田水利新质生产力的关键内容展开重点研究,最后从理论研究、技术创新和农田改造3个方面提出未来研究展望,为农田水利新质生产力的形成和发展提供参考。

2种豆科牧草生产性能与营养价值比较研究

为丰富云南草田轮作中优质豆科牧草种质资源,试验对黄花鸡足豆(Ornithopus compressus L.)开展了生产性能和营养价值评价研究。结果得出,黄花鸡足豆在云南温带地区具有良好的适应性,鲜草产量为15 525kg/hm^(2),干草产量为7 091.53kg/hm^(2),两者均高于光叶紫花苕,尤其是干鲜比较后者提高了27.8%。营养成分方面,光叶紫花苕的粗蛋白含量为17.43%,比黄花鸡足豆高出了3.09%(P<0.05),而黄花鸡足豆的P含量为0.25%,显著高于光叶紫花苕(P<0.05)。黄花鸡足豆的粗纤维含量为38.39%,高于光叶紫花苕,但是差异性不显著。综合营养成分分析,黄花鸡足豆与目前大面积利用的光叶紫花苕相比,营养价值较为一致。