模糊聚类技术在甘蔗种植户信息分析中的应用

利用数据挖掘中的模糊聚类分析方法,获取具有不同种植行为特征的甘蔗种植户群组。这有助于制糖企业对各群组作深入分析及制定相应的关怀策略。     

计及联络线方式的配电网规划方法

在建立配电网规划主模型的基础上，通过求取可行联络线集合建立配电网规划的联络线模型。结合图论中的邻接矩阵，提出路径矩阵和路径子矩阵的概念及形成方法，进而提出求取可行联络线集合的算法。实例证明．所提供的方法可有效提高配电网可靠性。     

农民的分化与农业劳动力转移

现代文明发展的历史表明,工业化过程是从农业向第二、三产业大量转移劳动力开始的,而农业劳动力的转移又是以农民分化为发端的。联产承包家庭经营体制的形成和发展、非农业与城镇的发展、城市的社会经济体制改革和国际产业结构的调整与升级、农村市场经济体制的建立与完善是中国农民分化的主要原因。农业生产结构的调整促进了农民的分化,需要大量转移农业剩余劳动力,而农业大量剩余劳动力的转移,又加剧了农民的进一步分化。     

基于多参数耦合的蓄冷温控箱冷板对流换热参数优化

蓄冷温控箱利用低温相变材料储存冷量,通过缓慢释放调节并保持箱内温度,目前仍存在冷量释放速率无法控制、剩余冷量预测难等问题,而蓄冷板表面对流换热系数直接影响冷量的释放速率。针对以上问题,搭建了蓄冷板表面对流换热系数测量试验平台,研究不同环境及蓄冷板参数对表面对流换热系数的影响。采用二次回归正交试验设计方案,探究了蓄冷区进口空气流速、进口空气温度、蓄冷板传热面积以及蓄冷板间距对表面对流换热系数的影响,并对结果进行分析,建立了表面对流换热系数二阶预测模型,获得影响表面对流换热系数大小较显著的因素及较优的参数组合。试验结果表明：各因素间存在明显交互作用,进口空气温度和蓄冷板传热面积的交互效应最大;通过响应曲面法建立的表面对流换热系数预测模型,得到最优参数组合为：进口空气流速4 m/s,进口空气温度25 ℃,蓄冷板传热面积0.455 m2,蓄冷板间距0.04 m,R2值为0.927 4,变异系数CV为5.78%。回归模型计算结果与试验结果吻合,最大误差为3.58%,平均相对误差为2.69%,表明该模型可以快速、准确地预测不同条件下的蓄冷板表面对流换热系数。试验结果为蓄冷温控箱冷量释放速率精准调控及剩余冷量预测提供参考。     

Transfer of carbon incubation parameters to model the SOC and SON dynamics of a field trial with energy crops applying digestates as organic fertilizers

The fertilization with organic amendments and digestates from biogas plants is increasingly used to increase carbon stock and to improve the soil quality, but little is still known about their long-term effects. A common method to analyse organic amendments and their mineralization is incubation experiments, where amendments get incubated with soil while CO₂ release is measured over time. In a previous study, carbon models have been applied to model the carbon dynamics of incubation experiments. The derived parameters describing the carbon turnover of the CCB model (CANDY Carbon Balance) are used to simulate the SOC and SON dynamics of a long-term field trial. The trial was conducted in Berge (Germany) where organic amendments like slurry, farmyard manure or digestates were systematically applied. To grant a higher model flexibility, the amounts of crop residues were calculated for roots and stubble separately. Furthermore, the mineralization dynamics of roots and stubble are considered by the model parameters for each crop. The model performance is compared when using the dry matter and carbon content received from the field trial and the incubation experiments, to evaluate the transferability. The results show that the incubation parameters are transferable to the field site, with rRMSE < 10% for the modelled SOC and rRMSE between 10% and 15% for the SON dynamics. This approach can help to analyse long-term effects of unexplored and unusual organic fertilizers under field conditions, whereat the model is used to upscale the C dynamics from incubation experiments, considering environmental conditions.     

基于改进DenseNet和迁移学习的荷叶病虫害识别模型

病虫害的发生将会严重影响莲藕品质与产量,开展病害诊断与识别对藕田病虫害及时对症对病诊治、提升莲藕生产质量与经济效益具有重要意义。该研究以荷叶病虫害高效、准确识别为目标,提出了一种基于改进DenseNet和迁移学习的荷叶病虫害识别模型。采用分支结构对模型的浅层特征提取模块进行改进,并在Dense Block与Transition Layer中引入Squeeze and Excitation注意力机制模块和锐化的余弦卷积,最后基于Plantvillage数据集进行迁移学习,实现了91.34%的识别准确率。该研究实现了对荷叶腐败病、病毒病、斜纹夜蛾、叶腐病、叶斑病的识别,并将改进后的模型推广应用于基于无人机图像的藕田病虫害检测,实现了病害分布可视化,可对莲藕病虫害的智能化防治提供有益指导。     

Plant Response to Copper Toxicity as Affected by Plant Species and Soil Type

ABSTRACT

A greenhouse experiment was conducted to determine the bioavailability of copper (Cu) in clay loam and sandy clay loam soil. Lettuce (Lactuca sativa) and spinach (Spinacia oleracea) were grown in pots for 45 d. When mature, plants were treated for 15 additional days with 0, 100, 250, 500, or 1000 mg Cu kg^?1 as CuSO₄·5H₂O. After harvest, Cu in soils and plant tissues was determined. In soils, applied Cu raised total and EDTA-extractible Cu. Results also revealed that the amounts of Cu extracted from sandy clay loam soil (80%) were higher than those extracted from clay loam soil (70%). In plants, increasing soil Cu concentration increased plant concentration of the metal. Plant species vary in their capacity for Cu accumulation: Lettuce has a relatively higher potential for Cu uptake and translocation than does spinach. Cu accumulation also differs among plant organs. In lettuce, metal accumulation is higher in roots than in shoots, where 60% to 80% of the total Cu of the plant is located in the roots. However, in spinach, there is no significant difference in Cu content between roots and shoots. The transfer of the metal from soil to plant is higher for plants grown on sandy clay loam soil. For a given rate of applied Cu, metal content in plant tissues is higher on sandy clay loam soil due to its higher transfer coefficient (C_T) from soil to plant. Nevertheless, all crops studied showed a positive linear relationship between extractible soil Cu and plant Cu.     

Field assessment of cadmium,lead and zinc contamination of soils and leaf vegetables under urban and peri-urban agriculture in northern Nigeria

Urban and peri-urban agriculture in dry semi-arid northern Nigeria relies on untreated wastewater for all-year irrigation and the production of vegetables for urban markets. Human and animal exposure to potentially toxic metals is attributed to the consumption of vegetables raised in metal-polluted soils. The objective of this study was to determine the bioavailability and soil–plant transfer of Cd, Pb and Zn to amaranthus (Amaranthus caudatus) and lettuce (Latuca sativa) raised in the garden fields and to assess their safety for human consumption. Ten farmers’ fields were selected per location for analysis of Cd, Pb and Zn in soils and vegetables. Whereas total concentrations of Cd and Zn were greater than the safe or permissible limits for agricultural soils, the Pb concentration was less than its maximum allowable concentration. However, the concentration of Pb and Cd in edible portions of amaranthus exceeded the safe limit for human consumption by 7–13 times, while lettuce exceeded the limit by 11–17 times. Cadmium was more rapidly transferred from soil through root to shoot than Zn > Pb. The plant tissue concentrations of the metals were not significantly correlated with the Diethylene triamine pentaacetic acid (DTPA) and dilute CaCl₂-extractable concentrations of the metals in the soils. Furthermore, permissible limit of Pb established as standards for agricultural lands may not be suitable to ensure produce safety in Urban and peri-urban agriculture (UPA) in the city of Kano.     

河岸带土壤溶解性有机质垂直分布特征及其性质研究

河岸带有机质（Soil organic matter,SOM）的迁移转化在有机碳从陆地生态系统向水域生态系统中迁移转化及污染物的迁移转化中起到了重要的作用。以崇明岛典型河岸带为研究对象,分析了不同区域河岸带土壤有机碳（Soil organic carbon,SOC）、土壤溶解性有机碳（Soil dissolved organic carbon,SDOC）垂直分布特征和三维荧光光谱（Excitation—Emission matrix,EEM）特征,探讨了河岸带对土壤溶解性有机质（Soil dissolved organic matter,SDOM）性质及其潜在环境影响。结果表明：表层土壤（0—30cm）SOC储量占采样深度土壤SOC的40％左右,SDOC占SOC的5％左右,从陆上区域到缓冲区域表层土壤SDOC呈累积效应。河岸带有机质主要来自河岸带植物残体及其代谢产物,地下水也可能是河岸带土壤DOM的另一来源,河岸带土壤中大部分类腐殖质被表层矿物质所吸附。在土壤系统中,综合应用荧光指纹指数[荧光指数（Fluorescence index,FI）,生源指数（The index of recent autochthonous contribution,BIX）和腐殖化指数（Humification index,HIX）]可以有效地揭示其来源和特性,但在土壤体系中单独应用指纹指数需审慎。     

烟草对土壤铅的吸收、转运及分配特征

采用室外盆栽试验方法,开展烟草不同生育期铅吸收转运及分配特征的研究。结果表明：土壤铅处理对烟草生长有较明显的抑制作用,且生育前期比生育后期更明显;烟草根系对铅的阻滞作用较强,以限制铅由根系向地上部运输。烟草各生育期根、茎和叶中铅含量均随土壤铅浓度的增加而升高,其中根部的上升幅度最大,随着生育期的推进,烟草各器官铅含量从团棵期至现蕾期呈现先降低后升高的趋势,根部铅含量从现蕾期至成熟期呈现下降趋势。土壤添加外源铅后,烟草生育期内茎和叶的铅转运系数分别介于0．35—1．00和0．25～0．91之间,茎和叶的转运系数随着铅浓度的增加和生育期的推进呈下降趋势。烟草各器官中铅含量介于13．8～180．74mg·kg^-1之间,各器官铅含量的分布规律为根〉茎〉叶,各器官铅积累量总体为叶〉根〉茎,但成熟期在T2和T3处理下表现为根〉叶〉茎。在土壤铅浓度较低时,烟草体内铅较易向地上部分转运,旺长期至现蕾期阶段是烟草体内铅向地上部分转运的关键时期。