杨梅根瘤内生菌的回接侵染特性

采用不同的接种方法对1株杨梅根瘤内生菌进行了回接侵染试验。结果表明：这株根瘤内生菌对杨梅幼根具有很强的感染能力，而且不同的接种方式对弗兰克氏菌回接侵染效果会产生一定的影响。菌体分批接种、菌龄6—8周、苗龄4周、接种量20mg／株(湿菌体)，能够产生高效的共生效果。     

夏玉米测土配方专用肥的施用效果

[目的]明确夏玉米种植前土壤养分状况,评价基于土壤养分供应状况生产的测土配方专用肥的应用效果。[方法]2006~2007年在河北省清苑县、河北农业大学实验农场开展小麦-玉米测土配方施肥的试验示范工作。[结果]针对土壤养分含量状况,提出"稳氮增磷控钾"的施肥方针。因测土配方施肥,增效达1 116元/hm2,使用配方肥平均节约肥料成本300元/hm2。[结论]测土配方专用肥可以明显提高夏玉米产量,降低肥料投入成本,增加农民收益。     

融合粗糙集和证据理论的温室环境控制推理决策方法

针对温室环境控制专家决策的需求,该文提出了一种融合粗糙集和证据理论的推理方法,建立基于粗糙集和证据理论的决策模型,模型推理流程包括连续属性离散化、专家决策表形成、属性约简、证据组合推理。首先采用模糊C均值聚类方法离散连续的环境指标数据,利用基于信息熵的属性约简算法对决策表进行优化,剔除专家知识中的冗余成分,然后引入证据理论组合优化后的指标,最后依据基于基本可信度分配的决策,判定温室应采取的控制方法。实例研究表明该方法能有效提高控制决策可信度,减小决策的不确定性,将其应用于温室环境控制决策具有可行性。     

深化改革提高"两课"教学的实效性

高等院校开设的“两课”是对大学生进行系统的马克思主义理论教育和思想政治教育的主渠道和主阵地,在培养大学生成为中国特色社会主义事业的建设者和接班人方面起着十分重要的作用。结合贯彻落实中共中央“十六号”文件精神,从统一思想认识、提高教师自身素质、更新教学内容、创新教学形式和手段等方面对提高“两课”教学的实效性进行了探讨。     

农业生产资料价格对橘农收入的影响

采用1989~2006年的时序数据,通过建立向量自回归模型考量我国农资价格上涨与橘农收入之间的动态影响关系,并在对VAR模型进行残差检验和稳定性检验的基础上,运用脉冲响应函数和预测方差方法进行经济计量分析。研究结果表明,橘农每亩纯收入对农资价格上涨有负向响应并趋向稳定;农资价格上涨对橘农每亩纯收入增长有正向响应并趋向稳定。为有效防止我国农资价格大幅度上涨对橘农增收产生负面影响,政府应健全农资调控机制,取消农资生产和流通环节的补贴政策,对橘农实行直接补贴;建立中央和地方两级农资储备制度,平抑农资市场价格季节性波动;完善农资连锁经营体系,降低农资流通成本。     

水果型番木瓜外植体灭菌方法研究

以水果型番木瓜成龄株顶芽和侧芽为外植体,研究不同灭菌剂组合和灭菌时间、抗生素组合对外植体的灭菌效果。结果表明,3种灭菌剂组合对外植体的灭菌效果优于两种灭菌剂组合;3种灭菌剂组合中以采用0．1％KMnO4浸泡10min→5％NaClO浸泡10min→0．1％HgCl2浸泡8min的灭菌效果最好,外植体成活率最高,为47．27％。经不同抗生素组合灭菌,外植体平均污染率和成活率分别为28．57％～45．16％、54．84％～71．43％,灭菌效果明显优于对照,说明抗生素组合可以有效降低水果型番木瓜外植体的内源菌污染,提高其成活率,其中以MS＋6-BA1．5rag／L＋庆大霉素80mg／L＋头孢噻肟钠500mg／L的效果最好,利于获得番木瓜无性系。此外,以幼苗顶芽作为外植体进行灭菌培养的效果优于侧芽,利于促进外植体的萌动生长和形成丛生芽。     

Functional mechanisms of drought tolerance in maize through phenotyping and genotyping under well watered and water stressed conditions

Developing tolerant genotypes is crucial for stabilizing maize productivity under drought stress conditions as it is one of the most important abiotic stresses affecting crop yields. Twenty seven genotypes of maize (Zea mays L.) were evaluated for drought tolerance for three seasons under well watered and water stressed conditions to identify interactions amongst various tolerance traits and grain yield as well as their association with SSR markers. The study revealed considerable genetic diversity and significant variations for genotypes, environment and genotype × environment interactions for all the traits. The ranking of genotypes based on drought susceptibility index for morpho-physiological traits was similar to that based on grain yield and principal component analysis. Analysis of trait – trait and trait – yield associations indicated significant positive correlations amongst the water relations traits of relative water content (RWC), leaf water potential and osmotic potential as well as of RWC with grain yield under water stressed condition. Molecular analysis using 40 SSRs revealed 32 as polymorphic and 62 unique alleles were detected across 27 genotypes. Cluster analysis resulted in categorization of the genotypes into five distinct groups which was similar to that using principal component analysis. Based on overall performance across seasons tolerant and susceptible genotypes were identified for eventual utilization in breeding programs as well as for QTL identification. The marker-trait association analysis revealed significant associations between few SSR markers with water relations as well as yield contributing traits under water stressed conditions. These associations highlight the importance of functional mechanisms of intrinsic tolerance and cumulative traits for drought tolerance in maize.     

崇明种植业农用化学品投入动态分析与控制对策

调查分析了2000-2005年崇明县种植业农用化学品使用情况;并结合崇明岛的气候、农业生产及地域等特点,探讨了农用化学品使用对崇明生态环境建设的影响;为把崇明建设成生态岛,提出了农用化学品控制对策。     

基于加速度传感器的本交笼种鸡个体行为监测与识别

为了监测种鸡行为、了解鸡群的健康状况,实现本交笼养下种鸡个体行为的自动识别,设计了一种基于九轴加速度传感器和蓝牙无线传输的本交笼种鸡个体行为实时监测系统。采用小波sym降噪对原始数据预处理,根据不同行为的加速度曲线波动性提取加速度数据特征值,利用K-means聚类算法对行为特征进行识别,得到稳定的聚类中心;进行了加速度传感器读写距离测试和以充电宝、锂电池作为供电设备的供电情况对比;同时利用视频监控验证种鸡的5种行为。结果表明,该系统能够快速且连续不间断地采集本交笼种鸡个体行为信息,准确识别种鸡个体的多种行为,采食行为平均识别精度为94.31%,饮水行为平均识别精度为92.53%,打斗行为平均识别精度为84.03%,交配行为平均识别精度为72.00%,振翅行为平均识别精度为9231%。本研究有助于无损、快速识别种鸡个体行为,为本交笼养模式配套设施设备优化设计和高效管理提供科学依据。     

Identifying soil management zones in a sugarcane field using proximal sensed electromagnetic induction and gamma‐ray spectrometry data

Spatial variation in soils is required to supply ameliorants and fertilisers in the Australian sugarcane industry. However, traditional approaches are cost‐prohibitive. We investigated how a digital soil mapping (DSM) approach could be used to identify management zones. First, ancillary data including electromagnetic induction and gamma‐ray spectrometry data were collected. Using fuzzy k‐means (FKM) clustering, two to six management zones were identified. A similar approach was used to cluster percentage yield variations (2014, 2015 and 2016). Using restricted maximum likelihood analysis of topsoil (0–0.3 m) and subsoil (0.6–0.9 m) physical (e.g. clay) and chemical (e.g. exchangeable sodium percentage [ESP], and exchangeable calcium and magnesium) properties, three zones were found to minimise the mean squared prediction error (). By comparison, the three zones obtained using the percentage yield variation only minimised for subsoil ESP, which suggested it had some influence on sugarcane yield and productivity. Different rates of gypsum were required to manage the moderately sodic topsoil ESP for each zone. This was similarly the case with lime to overcome deficiencies in exchangeable calcium and magnesium. The results were consistent with yield variance, suggesting the smaller yield in some zones was due to topsoil sodicity and strongly sodic subsoil with a greater clay content. We concluded that the DSM approach was successful in identifying soil management zones and can be used to improve soil structural stability and fertility. The zones also had ramifications for strip trials to determine yield increases by comparing variable rate applications of gypsum and lime.