应用土壤质地预测干旱区葡萄园土壤饱和导水率空间分布

田间表层土壤饱和导水率的空间变异性是影响灌溉水分入渗和土壤水分再分布的主要因素之一,研究土壤饱和导水率的空间变化规律,有助于定量估计土壤水分的空间分布和设计农田的精准灌溉管理制度。为了探究应用其他土壤性质如质地、容重、有机质预测土壤饱和导水率空间分布的可行性,试验在7.6 hm2的葡萄园内,采用均匀网格25 m×25 m与随机取样相结合的方式,测定了表层(0～10 cm)土壤饱和导水率、粘粒、粉粒、砂粒、容重和有机质含量,借助经典统计学和地统计学,分析了表层土壤饱和导水率的空间分布规律、与土壤属性的空间相关性,并对普通克里格法、回归法和回归克里格法预测土壤饱和导水率空间分布的结果进行了对比。结果表明:1)土壤饱和导水率具有较强的变异性,平均值为1.64 cm/d,变异系数为1.17;2)表层土壤饱和导水率60%的空间变化是由随机性或小于取样尺度的空间变异造成;3)土壤饱和导水率与粘粒、粉粒、砂粒和有机质含量具有一定空间相关性,而与土壤容重几乎没有空间相关性;4)在中值区以土壤属性辅助的回归克里格法对土壤饱和导水率的预测精度较好,在低值和高值区其与普通克里格法表现类似。研究结果将为更好地描述土壤饱和导水率空间变异结构及更准确地预测其空间分布提供参考。     

黄土高原刺槐和侧柏根系固坡的有限元数值模拟

为探讨黄土高原主要造林树种刺槐和侧柏根系对土质边坡稳定性的作用,该文以刺槐(Robinia pseudoacacia)和侧柏(Platycladus orientalis)为例,应用有限元数值模拟法构建二维造林边坡稳定性分析模型,研究林木根系的空间异质性对水平阶整地坡和对照自然坡稳定性的影响。研究发现:1)无论是否经过整地处理,造林都可以提高边坡的稳定性,且刺槐根系的固土效果优于侧柏根系(P0.001);2)在不考虑水文过程的前提下,水平阶整地模式的人工林边坡稳定性优于对照自然坡;3)当根系表观附加黏聚力增加到某一阈值后,造林边坡的安全系数进入平稳阶段不再大幅上升,说明边坡稳定性模型对根系附加黏聚力计算法的精度并不敏感,揭示了根系固坡领域的研究重点应从过去的试图提高根系附加黏聚力的计算精度转变为提高评价造林边坡稳定性的准确性;4)根系附加黏聚力随坡位的变化而变化,两树种没有明显的规律,但安全系数均表现出较敏感于坡下位根系,建议在林分经营管理中充分利用坡下位林木的固土效益。该研究成果可为黄土高原地区浅表层滑坡灾害的防治工作提供理论依据。     

农业院校《检测技术》课程教学改革实践

《检测技术》课程是我校农业电气化及相关专业的一门专业基础课。针对该课程传统教学存在的不足,对该课程理论教学改革进行了探讨,提出了课堂理论教学以启发讲授与实例分析为主,重点放在传感器的应用上;多媒体课件与板书相结合,理论讲解、交流讨论交替进行的教学理念。这些改革措施有利于提高学生的专业素质、创新意识和实践能力,收到了良好的教学效果。     

Collecting and Using Autobiographical Memories in Rural Social Research: A Step-by-Step Guide

Human autobiographical memory, containing information on the self and its sociocultural surroundings, is a unique reservoir of knowledge, valuable in rural social research as well as in several other fields of study. However, the use of autobiographical memories as a source of retrospective information in (rural) social research remains largely underappreciated. This article introduces a five-step guide for designing and implementing research based on individuals’ cued autobiographical memories. The article also briefly outlines some major phenomena associated with human autobiographical memory (reminiscence bump, mood-incongruency, overgeneral memory, telescoping effect) and explains how they can affect a study based on participants’ autobiographical memories.     

Factors Influencing Use of Traditional Communication Methods in Information Dissemination Among Farmers in Osun State,Nigeria

Critical factors influencing farmers’ use of traditional communication methods (TCMs) in information dissemination were isolated with a factor analytical technique. The results show that most of the farmers were between 31 and 60 years and the majority (63%) employ use of TCMs such as proverbs, hooting, putting leaves on path, and use of palm fronds to deliver information at a moderate level. The features of TCMs, farmers’ personal characteristics, economic proficiency, and influence of social contact were factors influencing use of TCMs. It was concluded that use of TCMs is influenced by their peculiarities in discerning information and the user's personal and socioeconomic characteristics.     

草地生态系统健康研究述评

阐述了草地生态系统健康的研究进展、存在问题和发展趋势,重点介绍了评价的指标体系和方法,包括结构功能指标体系法、综合指标体系及10多种方法的特点和适用情况.同时对于指标的筛选、权重的确定、标准的划分等难重点问题给出了建议.提出了用多种方法来评价同一研究对象来进行比较和矫正的观点,并强调形成集自然、经济、社会、人类健康为一...     

Modelling population dynamics and response to management options in the poultry red mite Dermanyssus gallinae (Acari: Dermanyssidae)

The poultry red mite Dermanyssus gallinae is a major pest and widespread ectoparasite of laying hens and other domestic and wild birds. Under optimal conditions, D. gallinae can complete its lifecycle in less than 10 days, leading to rapid proliferation of populations in poultry systems. This paper focuses on developing a theoretical model framework to describe the population dynamics of D. gallinae. This model is then used to test the efficacy and residual effect of different control options for managing D. gallinae. As well as allowing comparison between treatment options, the model also allows comparison of treatment efficacies to different D. gallinae life stages. Three different means for controlling D. gallinae populations were subjected to the model using computer simulations: mechanical cleaning (killing once at a given time all accessible population stages), sanitary clearance (starving the mite population for a given duration, e.g. between flocks) and acaricide treatment (killing a proportion of nymphs and adults during the persistence of the treatment). Simulations showed that mechanical cleaning and sanitary clearance alone could not eradicate the model D. gallinae population, although these methods did delay population establishment. In contrast, the complete eradication of the model D. gallinae population was achieved by several successive acaricide treatments in close succession, even when a relatively low treatment level was used.     

葡萄冷藏中电学参数与质地特性变化规律

为了探讨采后葡萄电学参数与质地特性的变化规律,以红地球葡萄为材料,利用HIOKI 3532-50型LCR测量仪和自制平行板铜电极,在0.1～3?980 kHz频率范围内选取24个频率点,对采后冷藏果实进行了电学参数的动态测定,并研究了其与果实质地参数硬度、咀嚼性、黏着性和弹性之间的相关性,筛选出了电学参数较佳测试频率,建立了电抗X与质地参数的二元二次回归方程。结果表明,葡萄果实复阻抗Z、电感Lp、电抗X和电阻Rp随测试频率升高呈指数形式下降;在同一频率下,果实Z、Lp、X和Rp随着贮藏时间的增加呈线性下降趋势。随着果实的衰老,质地参数硬度和咀嚼性逐渐下降,黏着性绝对值和弹性呈上升趋势。在较佳测试频率0.1 kHz下,电学参数与质地参数呈现较高相关性,其中电抗X与硬度、弹性、黏着性呈现显著相关性（P<0.05）,同时与咀嚼性达到较高相关性,并建立了二者之间的关联方程,为实现葡萄无损检测提供了依据。     

品种筛选多环境测试作图分析方法

作图分析是挖掘品种多环境测试信息的有效手段。为充分挖掘测试信息,高效而准确地实现品种评价、筛选与预测这一目标,有必要引进更多可适用众多性状、易于理解和使用的直观作图分析方法。该研究根据近年分析品种多环境测试的经验,提出3种作图分析方法——雷达图、蜡烛图和条件格式,以国家玉米品种区试数据为例,对3种作图方法的使用进行分析。结果表明：3种方法均为适用于品种多环境测试数据的有效作图分析方法,对不同观测性状均可适用,并易于理解和使用;雷达图有助于多指标综合分析,包括品种或环境的认知度、一致性分析,以及品种的筛选和对比;蜡烛图有助于单指标的详细对比和规律挖掘,如试点区辨力、品种稳定性与优异性规律等;条件格式则是数据浏览与直观表达的结合。应用3种作图方法可提高多环境测试的决策效率。     

养鱼池塘机械拖网捕鱼系统的设计与试验

针对目前池塘拖网捕鱼作业完全靠人力,工作效率低的问题。通过在池塘两侧设置网具引导钢丝绳,利用液压绞车及拖引装置实现连续拖网的方法,开发了一套池塘机械拖网捕鱼系统。试验结果为：拖网系统在规格为50 m×100 m池塘进行机械拖网试验,拖网速度为10 m/min,拖网人员由12人减少至5人,拖网捕鱼效率约64.8%。机械拖网大幅减少了作业人数,运行稳定,适用于各类矩形池塘的捕捞作业。