Feeding quality assessment of fresh maize stover by means of near-infrared spectroscopy with a new sample presentation unit

Stover quality traits are important in breeding programmes of maize cultivars. However, conventional procedures for evaluation of stover quality are expensive and thus limit the full exploitation of the available genetic variability. Our objective was to assess the potential of near‐infrared spectroscopy (NIRS) with a new sample presentation unit to determine feeding quality of maize stover. The plant material comprised maize inbreds and hybrids. The sample presentation unit was equipped with a near‐infrared diode‐array spectrometer. Coefficient of determination in cross‐validation ranged between 0.77 and 0.94 for contents of dry matter, nitrogen, neutral detergent fibre and in vitro fermentability expressed as gas volume after 24h incubation time, but it was lower for ash content. It was concluded that NIRS with the new sample presentation unit was less accurate than laboratory NIRS to predict the standard reference methods. However, the new sample presentation unit might be used as a fast and efficient technique to perform large screenings of maize stover accessions in breeding programmes.     

中国饲料数据库浅析

中国饲料数据库是“七五”国家攻关课题。它包括饲料营养价值评定、饲养标准、饲料标准、饲料配方、饲料工业信息、畜禽渔业信息等子系统。具有输入，数据处理、编辑打印输出，优化饲料配方、更新等功能。它是应用现代化管理技术，使营养、饲料科研成果中的数据条理化、标准化，使各种信息集中贮存，统一管理。中国饲料数据库的研究成功和推广应用，已取得巨大的经济效益和社会效益。     

宽须蚁蝗蝗蝻空间分布型的研究及其应用

应用3种检验分布型的方法分别检验了宽须蚁蝗蝗蝻的分布型。结果表明：宽须蚁蝗蝗蝻在草地上的空间分型呈聚集分布,其聚集强度随种群的密度的升高而增加,应用Iwao模型中的参数估计了田间调查时的最适抽样数。     

水匮乏指数在区域水安全评价中的应用

针对水安全问题,以农垦红兴隆分局为例,采用水匮乏指数和样本均值-标准差分级法对红兴隆分局下属12个农场2006年的水安全状况进行了评价和分级,并根据分级结果提出了相应的对策。结果表明,八五三和红旗岭农场的WPI值处于安全状态,水安全状况最为乐观;饶河农场的WPI值处于较高安全状态,水安全状况较好;友谊、五九七、八五二、二九一和江川农场的WPI值处于中等安全状态,水安全保障体系有待于进一步加强;北兴农场的WPI值处于较低安全状态,水安全状况较差;而双鸭山、曙光和宝山农场的WPI值处于不安全状态,水安全状况最差。     

GIS支持下的永久基本农田建设区域划定

基本农田是耕地的精华,全面划定永久基本农田对土地整治规划和基本农田建设有重要现实意义,也是2016年国家政府工作报告中的重点工作内容。从基本农田质量、基本农田地形条件、基本农田区位条件、基本农田区位设施状态等方面构建评价指标体系,利用线性加权综合评价法,并基于GIS技术,以湖北省当阳市为例,研究如何划定永久基本农田建设区域,以期为县域永久基本农田建设和耕地的持续利用提供参考。     

光谱技术结合水分校正与样本增广的棉田土壤盐分精准反演

棉田土壤盐分的精准反演对于棉花的种植管理具有重要意义。水分和盐分作为主要环境因素,共同影响棉田土壤的波谱特征,两者之间的耦合关系直接影响土壤盐分的检测分析。为了提高基于光谱技术构建的模型对棉田土壤盐分信息解析的准确性与可靠性,该研究联用可见/短波近红外（400～1 000 nm）和长波近红外（960～1 693 nm）技术,采集不同含水率与含盐量的新疆地区土壤样本的光谱;结合外部参数正交法（external parameter orthogonalization,EPO）,校正不同标样集与不同波段光谱中的土壤含水率干扰信息;引入基于不同卷积步幅的深度卷积对抗网络（deep convolutional generative adversarial networks,DCGAN）,进行样本增广与质量评估;参考三层残差神经网络设计一维卷积神经网络RNet,最终构建基于EPO-DCGAN-RNet的优化模型,用于棉田土壤盐分的反演。结果表明,与传统机器学习方法和基于VGG或EfficientNet结构一维卷积神经网络相比,该研究提出的EPO-DCGAN-RNet方法能够有效地滤除水分对盐分反演的影响、提高模型对特征波段的挖掘能力、降低深度学习算法对样本量的依赖性,并能得到更优的模型预测性能。EPO-DCGAN-RNet的建模集R²和均方根误差分别为0.942、115.420 μS/cm,验证集R²和均方根误差分别为0.910和136.472 μS/cm。研究结果可为新疆棉田土壤盐分快速精准检测提供理论指导和技术支持,有助于促进盐碱地区棉花种植的水肥科学管理。     

森林资源清查中植被调查与统计技术研究

文章提出了利用森林资源连续清查固定样地进行植被种类和生物量调查的技术方法。此方法通过选择适当时间，提高调查者相关知识，确定样地数量等措施，可满足植物区系调查的要求，对于植被类型确定，植物蕴藏量统计，经济植物开发利用保护的决策，植被演替规律的观测具有实用价值。     

气相色谱-电子捕获检测器测定电子废弃物处理场地底泥中的四溴双酚-A

通过优化分析仪器的条件设置，建立了使用气相色谱-电子捕获检测器技术分析四溴双酚-A（TBBP—A）的仪器分析方法。样品采用正己烷索氏提取、硅胶柱分离纯化、外标法定量，结果表明，测定方法在测量范围内具有良好的线性关系，测定的平均回收率为86．8％，检出限为5．0ng／ml，相对标准偏差为3．26％～8．77％：     

Larger body size with higher predation rate

Abstract –  Many studies have reported that prey fish increase in body size with an increase in piscivore abundance, and this change may be explained mainly by two processes: release from intraspecific competition because of a reduction in the prey fish population and size-dependent selection by the piscivore. However, the evolutionary mechanism is not yet fully understood. Here, we first show the body-size dynamics of the semelparous gobiid fish Gymnogobius isaza , which is one of the prey fishes of the introduced largemouth bass, Micropterus salmoides . The data show the possibility that the goby body size might have changed in parallel to the number of largemouth bass from 1975 to 2002, which may be one of the best examples of the positive relationship between body size and predation rate. Furthermore, we explored a mathematical model to consider a body-size change of semelparous fish from an evolutionary viewpoint. The model provided the following qualitative predictions: (1) the optimal assimilation rate increases with predation pressure; (2) a rapid large-scale increase in predation pressure may exterminate the prey fish because of delayed evolution of the assimilation rate; and (3) the optimal assimilation rate increases when the prey fish is more likely to die through predation than through natural mortality or when it is difficult to grow larger because of low resource availability or insufficient foraging efficiency. Moreover, we propose a theoretical framework to evaluate the relative effects of ecological and evolutionary processes over the long term.     

永磁同步电动机的全数字式控制系统

提出了一种永磁同步电动机直接转矩控制的全数字化实施方案，电流环采用了滞环控制技术，电流调节频率达到１０ｋＨｚ，为构成永磁同步电动机全数字式交流伺服系统创造了有力条件。