Prediction of winter wheat cultivar performance in Germany: At national,regional and location scale

Winter wheat cultivar recommendation is usually based on the cultivar performance observed in post-registration trials. In Germany, official recommendations are based on state cultivar trials, which are conducted individually by the federal states, usually over a period of three years. In each predefined winter wheat cultivation region a subset of registered cultivars is tested. The recommendation in a particular region is mainly based on the yields from trials on several locations in this region. Practically, the farmer's interest is a prediction of the yielding ability of cultivars on his own farm in the following growing season. This prediction can be made based on data from different scales, and with one year or multiple-year data. Here, we evaluated the prediction ability with the data from national, regional and location scales per se, and tried to find the optimal information source (scale and number of years) to predict the relative yield of a specific cultivar for a specific location. For this purpose, data from the country wide value testing trials from 1991 to 2001 carried out by the Federal Office of Plant Varieties (Bundessortenamt) were used. Winter wheat cultivation regions were adopted according to the German convention which gives the chance of further dividing the data into regional subgroups. The results of the analyses indicate that for a given location, the two years regional data have the highest predictive power for superior cultivars. Two years’ data from that specific location give the highest predictive power for intermediate and inferior cultivars. In general, the predictive power of single year data is much lower than of two years data. The results confirm the merit of the definition of different cultivation regions. By proper definition of regions, the multiple year data collected within the region have high predictive power for the cultivar performance for the locations within that region.     

供销合作社在完善农村现代流通体系中的作用

概述了我国农村流通体系的发展现状,指出在加快推进现代化进程中,供销合作社始终是一支重要力量,但流通体系城乡间的差距却存在扩大趋势.分析了供销合作社在农村物流体系中的作用,提出了完善我国农村流通体系的对策建议.新时期,应发挥供销合作社扎根农村、联系农民、点多面广的优势,积极开展综合改革,借助网络布局逐步优化农产品销售方式,发挥组织优势,逐步强化农村流通体系金融服务能力建设,扩大覆盖范围,逐步促进再生资源回收利用产业升级,不断扩大供销合作社在构建农村现代流通体系中的作用,把供销合作社打造成农民生产生活服务的主力军和综合平台.     

基于CDSSM的作物病害处方推荐方法

作物病害诊断积累了大量电子处方数据,对电子处方数据二次利用,实现作物病害处方智能推荐是植保领域重要的研究内容。对此,本文构建基于CDSSM的作物病害处方推荐模型,实现多种类作物病害的诊断和处方推荐。基于病害标准知识库对作物病害处方数据进行筛选,并进行数据扩充,同时结合领域知识构建标准处方库;构建基于CDSSM的作物处方推荐模型,根据文本特征生成语义向量,计算语义向量的余弦距离,结合标准处方库完成融合地区、时间、作物种类、生长期等多个因素的处方精准推荐。从病害诊断、处方推荐、针对番茄病害处方推荐和不同输入对处方推荐的影响4方面展开结果分析,并与基于DSSM、DSSM-LSTM、Cosine、Jaccard、BM25的模型结果进行对比分析;结合实际应用需求设计并构建面向移动终端的作物病害处方推荐应用“处方宝”。结果表明,基于CDSSM的作物病害处方推荐模型病害诊断正确率为71%,处方推荐准确率为82%,优于其他5种作物病害处方推荐模型;针对番茄病害处方推荐准确率更高。本文构建的基于CDSSM的作物处方推荐模型可以满足实际应用需求,还能够进行病害种类的扩充,可以作为作物病害处方推荐的高效辅助...     

Development approach and evaluation of the Nutrient Expert software for nutrient management in cereal crops

Meeting the demand for more food in the next 20–30 years requires intensifying cereal cropping systems and increasing current yields to about 70–80% of the genetic yield potential. A dynamic and robust nutrient management approach such as site-specific nutrient management (SSNM) will be essential to increase yields and optimize profits while maintaining the productivity of these intensive cropping systems. SSNM has increased yield and profit in rice, maize, and wheat in major cropping systems in Asia; but, crop advisors have found it complex and difficult to implement in the field. Nutrient Expert (NE) was developed to provide crop advisors with a simpler and faster way to use SSNM. NE enables crop advisors to develop SSNM recommendations using existing site information. Nutrient Expert for Hybrid Maize (NEHM) increased yield and profit of farmers in Indonesia and the Philippines. In Indonesia, NEHM increased yield by 0.9 t ha⁻¹, which increased profit by US$ 270 ha⁻¹ over farmer’s fertilizer practice (FFP). Compared with FFP, NEHM recommendations reduced fertilizer P (−4 kg ha⁻¹), increased fertilizer K (+11 kg ha⁻¹), and did not significantly change fertilizer N. In the Philippines, NEHM increased yield by 1.6 t ha⁻¹ and profit by US$ 379 ha⁻¹ compared with FFP. Compared with FFP, NEHM gave higher rates of all three nutrients (+25 kg N ha⁻¹, +4 kg P ha⁻¹, and +11 kg K ha⁻¹), which substantially increased fertilizer costs (US$ 64 ha⁻¹) but still increased profit by about six times the additional investment in fertilizer. NE accounts for the important factors affecting site-specific recommendations, which makes it a suitable starting point for developing nutrient management tools to reach more users.     

浅议高校多媒体教学中存在的问题及建议

多媒体教学以其形象生动的表现方式,被广大教师作为一种提高课堂教学效果的有效途径而广泛的运用,但是随着这种教学手段在课堂教学中的推广,也产生一些问题。在探讨目前应用多媒体教学中存在的普遍问题的基础上,提出了一些相应的建议,以提高多媒体教学的质量。     

江汉平原腹地中稻氮磷钾肥效及其适宜用量

通过在江汉平原腹地江北农场5个分场布置中稻的"3414"肥料效应试验,研究了氮、磷、钾肥对中稻产量和经济效应的影响。结果表明,施肥对中稻的增产效果明显,中稻施用氮肥的效果最好,磷肥次之,钾肥最小。稻谷最高增产695.1～2 414.7kg.hm-2,相应增产率为8.6%～37.8%,纯增收1 011.2～3 563.5元.hm-2。通过配置三元二次和一元二次肥效模型,结合田间试验实际情况,确定中稻的最佳施肥量为纯N180～200kg.hm-2,P2O555～60kg.hm-2,K2O 50～60kg.hm-2。     

基于Web的小麦品种布局优化决策支持系统

借鉴模糊评分法,根据用户对品种特性要求,计算小麦品种特征值的置信度,并建立小麦品种综合评价模型和基于置信度的品种选择模型;依据系统设计原理和组件化程序设计思想,通过藕合数据库技术、Web开发技术和模型技术,用可视化网页开发软件Tomcat 5.5、java语言及MySQL 5.0数据库,设计开发基于Web的小麦种质资源环境配置决策支持系统。该系统具有信息查询、综合评价、良种推荐和系统优化等功能,可为农业高效种植提供辅助决策服务。     

交城县测土配方施肥中的主要矛盾及建议

介绍了交城县测土配方施肥中存在的农业生产者的高度分散与配方肥料的规模生产,测土配方施肥工作量大与县级土肥技术力量严重不足,现有从事农业生产者的素质与测土配方施肥技术大面积应用,科学施肥指标体系建立滞后与当前大面积指导科学施肥之间的矛盾,并对矛盾产生的原因进行了分析,即认识不到位、专业技术人员少;在此基础上提出了加强统一领导、积极宣传培训、推广配方肥应用等建议。     

高校图书馆网上图书荐购系统的比较与分析

分析了64所重点大学图书馆的网上图书荐购情况,从功能模块的设计等方面对几种具有代表意义的网上图书荐购方式进行了比较,为图书荐购系统的设计提供参考。     

不同磷肥用量对高羊茅生长及养分吸收的影响

在武汉地区研究了不同磷肥用量对冷季型草坪草高羊茅Festuca arundinaces生长状况、草屑积累量、氮(N)磷(P)钾(K)养分含量及积累量的影响.结果表明:在施用N、K肥(N 15g/m2,K2O 12g/m2)基础上,P肥能明显促进草坪草分蘖并提高成坪后叶绿素含量,施P(P2O5)2.5～20.0g/m2处理的分蘖数是不施P对照的2.81～4.32倍,叶片SPAD值比对照高15.8～18.2.草屑积累量和高羊茅总干物量随P肥用量的增加而增加;施P 10.0g/m2范围内,地下部干物质量也随施P增加而增加,继续提高P用量有下降的趋势.高羊茅舍N量因施P而明显下降,地上部P、K含量随P肥用量增加而显著提高,而地下部P、K含量各处理差异不显著.P肥用量10.0g/m2时高羊茅N积累量达到最高值(7.51g/m2),是对熙的2.71倍;随着P用量的增加P、K养分积累量持续上升,且P积累量与P用量呈显著正相关.综合考虑草坪生长质量及肥料利用效率,认为在试验地力条件下新植高羊茅的P肥(P2O5)用量以5～10g/m2范围为宜.