太原市晋阳湖水质对蚕豆根尖细胞微核的影响

利用蚕豆根尖微核技术综合评价晋阳湖的水质污染情况。采集太原市晋阳湖5个样点的水,直接处理蚕豆根尖,检测各组水样对根尖细胞形成微核的诱导效应,并评价对应水体的污染程度。用晋阳湖5个水样点的湖水处理蚕豆根尖细胞的微核率为0.267%~1.767%,其中,渔场、电厂出水口、游泳处水样的污染较为严重,形成的微核率均高于0.7%,显著高于对照组水样(p0.05)。晋阳湖水质具有一定的遗传毒性效应,晋阳湖水已受到不同程度的污染。     

Formalizing agro-ecological engineering for future-oriented land use studies

Agriculture faces an array of interrelated problems that call for development of new and revision of existing cropping systems towards the multiple needs of the 21st century. Agro-ecological engineering approaches aimed at design and exploration of alternative land use systems at various scales may support the identification of appropriate land use options. Engineering approaches are based on mathematical representations of well-founded agro-ecological principles while taking into account available resources and prevailing land-related objectives. The goal of this paper is to contribute to the development of a formalized approach to engineer cropping systems at the land unit level that can be used as building blocks for systematic explorations of land use options at farm or regional scale. The approach for engineering cropping systems at the land unit level consists of three steps: (i) goal-driven design of cropping systems, (ii) quantification of biophysical production targets and (iii) definition of the optimal mix of inputs required to realize production targets. This paper describes the approach and illustrates it with examples from the Sudano-Sahelian zone of Mali. Explicit attention is paid to the required numerical tools and their application to analyze consequences of uncertainty in the performance of engineered cropping systems. Using numerical tools, uncertainty is made explicit with the aim to better manage or reduce it. Identification of uncertainty at the designer's desk allows taking uncertainty into account before applying engineered land use systems in regional model studies or testing such systems in practice. Problems related to the application of numerical tools are discussed, including the future role of agro-ecological engineering as independent discipline within agricultural science.     

Methods for Rapidly Measuring the Lodging Resistance of Wheat Cultivars

Lodging resistance ratings for winter wheat cultivars are frequently based upon observations of lodging. This is an unreliable method because of the frequent occurrence of years without significant lodging events. It also does not distinguish between stem and root lodging resistance. This paper describes the development and testing of instrumentation and procedures for two field‐based methods to rapidly assess stem and root lodging resistance. Both methods used a specifically designed instrument for measuring the resistance of shoots against rotational displacement. Stem lodging resistance was assessed when the soil was dry and strong, whereas resistance to root lodging was assessed after the soil had been weakened by irrigation. Tests were carried out on 14 winter wheat cultivars grown at two sites in the UK during 2002. Both methods were able to detect statistically significant differences between the cultivars for their resistance to stem and root lodging. A comparison of these results with observations of lodging in the field showed that the methods accounted for about 60 and 50 % of the stem and root lodging respectively.     

内蒙古巴盟小麦根病种类、数量及分布

1997～ 1999年 ,通过巴盟 5个旗 (县 )、2 0个乡、社的调查和 160 1份采集标样的室内病原菌分离、鉴定 ,结果表明 :巴盟地区小麦根病的主要病原菌为全蚀病菌 ,其分离频率最高为59 4 % ;次要病原菌有黄色镰刀菌 ,禾谷镰刀菌 ,麦根腐德氏霉 ,丝核菌 ,交链孢菌等 7种病原菌。全蚀病在 5个旗 (县 )均有不同程度的分布、发生数量约占根病的 80 %～ 90 %。     

统筹城乡背景下农机社会化服务的现状与实践—以成渝经济区为例

农机社会化服务是推动农业机械化发展的有效方式,新时期成渝经济区在统筹城乡社会经济发展背景下农机社会化服务正在进行着多元化的实践。为此,通过实证研究,分析了成渝经济区农机社会化服务的现状及作用,探讨了农机社会化服务与统筹城乡发展二者之间双向互动支撑的发展态势。同时,提出了促进成渝经济区农机社会化服务的针对性建议。     

不同喷灌定额下垄作沟播油葵根系生长及分布特征

垄作沟播喷灌技术是集垄作沟播与喷灌技术为一体的节水栽培技术.以不同灌水定额各设4个处理(灌水定额分别为24 mm、30 mm、36 mm、42 mm,灌水5次),以常规覆膜喷灌为对照(灌水定额42 mm,灌水5次).通过测定不同灌水处理下垄作沟播油葵根系生长及分布特征等指标,分析了不同灌水处理对油葵根系纵向、横向生长及...     

滴灌紫花苜蓿根层水分稳定同位素特征分析

为了明确滴灌紫花苜蓿根层水分运移,进一步阐明滴灌节水机理,采用液态水稳定氢氧同位素技术,分析了滴灌紫花苜蓿根层水分稳定氢氧同位素分布特征。结果表明,紫花苜蓿根层水分稳定氢氧同位素在下层富集,且随土壤剖面深度的增加同位素富集量有增加的趋势。滴灌条件下,紫花苜蓿根层发育有较多细根,可迅速而高效地利用灌溉水,灌溉后紫花苜蓿对灌溉水的利用不明确偏向于某一深度土层,根层内各土层土壤水均有利用。灌溉前土壤干旱时,滴灌紫花苜蓿以30 cm上下土层土壤水作为主要水分来源的概率较高。     

苹果采后加工碰撞损伤影响因素研究

针对苹果在清洗、分级和包装等采后加工过程中损伤率较高的问题,以红富士苹果为试验材料,利用自制的苹果跌落试验台,研究跌落高度、果实质量、碰撞材料对苹果碰撞损伤的影响.通过3因素3水平正交试验,分析试验因素对苹果碰撞损伤体积影响显著性;并通过试验确定苹果在2种碰撞材料下的碰撞损伤临界跌落高度.试验结果表明:影响苹果碰撞损伤...     

植保无人飞机作业参数对田外除草靶标区内外雾滴沉积规律的影响

雾滴大小、气象条件和施药装备的作业参数对雾滴的覆盖范围、靶标的吸附性能有影响.无人飞机(UAV)是目前有助于高效喷雾的现代施药技术装备.然而作业参数对靶标区和脱靶区的影响依然尚待确定.开展了田间试验并运用沉积扫描软件测定了在田外除草中不同飞行高度(2 m和3 m)和飞行速度(2 m/s和3 m/s)下雾滴的沉积量、覆盖...     

基于改进YOLO v4的生猪耳根温度热红外视频检测方法

基于热红外视频的生猪体温检测过程中,视频中保育期生猪头部姿态变化大,且耳根区域小,导致头部和耳根区域定位精度低,影响生猪耳根温度的精准检测。针对以上问题,本文提出了一种基于改进YOLO v4(Mish Dense YOLO v4,MD-YOLO v4)的生猪耳根温度检测方法,构建了生猪关键部位检测模型。首先,在CSPDarknet-53主干网络中,添加密集连接块,以优化特征转移和重用,并将空间金字塔池化(Spatial pyramid pooling, SPP)模块集成到主干网络,进一步增加主干网络感受野;其次,在颈部引入改进的路径聚合网络(Path aggregation network, PANet),缩短多尺度特征金字塔图的高、低融合路径;最后,网络的主干和颈部使用Mish激活函数,进一步提升该方法的检测精度。试验结果表明,该模型对生猪关键部位检测的mAP为95.71%,分别比YOLO v5和YOLO v4高5.39个百分点和6.43个百分点,检测速度为60.21 f/s,可满足实时检测的需求;本文方法对热红外视频中生猪左、右耳根温度提取的平均绝对误差分别为0.26℃和0.21℃...