基于多源Sentinel数据的县域冬小麦种植面积提取

冬小麦是我国主要的粮食作物之一,及时准确地获取冬小麦种植面积对农业政策的制定具有重要意义。以河南省扶沟县为研究区域,以多生育期Sentinel-1A和Sentinel-2A/B遥感影像为数据源,构建光谱特征、植被特征和极化特征的多生育期数据集,分析各类地物的特征曲线,采用随机森林算法对单生育期单传感器、单生育期多传感器、多生育期单传感器和多生育期多传感器的遥感影像进行精细分类,实现县域冬小麦制图。结果显示：单生育期的雷达影像无法满足制图要求,拔节期的总体精度最高,仅为62.9%,多生育期雷达影像分类精度达到81.9%,基本满足制图要求;单生育期的光学影像和融合影像在成熟期的精度最高,总体精度分别为93.4%和95.1%,Kappa系数分别为92.4%和94.8%,可以绘制较为精准的冬小麦分布图;多生育期融合影像绘制的扶沟县2019年冬小麦空间分布图,总体精度为96.8%,结果最优。研究结果表明融合的多生育期遥感影像可以为县域冬小麦种植面积的提取提供技术依据。     

非洲猪瘟背景下复养的消毒工作初探

自2018年8月以来蔓延的非洲猪瘟疫情给我国养猪业造成了巨大损失,生猪供应缺口凸显,猪价整体高位运行。安全顺利复产是规模猪场的优先选择,但由于准备不足、匆忙复产而导致失败的案例甚多;在目前没有相关疫苗的情况下,完善生物安全体系、彻底清除猪场内外残余病毒是规模猪场非洲猪瘟背景下复产的先决条件。笔者团队通过制订复养程序,指导某猪场进行非洲猪瘟复养消毒,各区域检测、复检为阴性后引入180头保育猪作为哨兵猪饲养2个多月,病原学和血清学检测结果均为阴性,复养初步成功。     

遥感作物制图辅助核事故农业风险决策

【目的】 将作物时空分布数据应用于核事故农业风险决策支持系统,体现遥感作物制图在核事故农业风险决策中的重要性。【方法】 文章以大亚湾核电基地为研究案例,对其周边地区的作物轮作系统进行遥感制图;作物时空分布数据经后处理,上传至核事故农业风险决策支持系统,实现作物样本任务的自动生成,以及放射性核素浓度的时空分布模拟。【结果】 提出的遥感制图方法可以在耕地破碎、云雨繁密区识别作物轮作系统,快速、准确地提供大范围作物时空分布数据。经过处理的作物时空分布数据,能够方便地应用于决策支持系统,辅助完成特定或优先区作物样本任务点的自动生成,以及放射性核素浓度时空分布的模拟。【结论】 遥感作物制图与核事故农业风险决策支持系统相结合,可进一步提高采样的有效性,提升放射性核素空间和时间分布模拟与预测的准确性。从而帮助决策者制定核污染监测和评估策略、修复计划,科学指导农业生产的恢复。未来,有必要深入研究遥感作物制图在核事故农业风险决策中的应用,充分发挥遥感技术与数据的优势,规避核事故对农业生产带来的风险。     

Biomonitoring using tagged sentinel fish and acoustic telemetry in commercial salmon aquaculture: A feasibility study

We tested if it is technically feasible to monitor fish in real-time in full-scale commercial fish farms using acoustic telemetry. 31 Atlantic salmon were equipped with acoustic transmitter tags containing depth sensors. Tagged fish were monitored for three months in two industrial scale sea-cages containing 180000 and 150000 fish, respectively. Each cage was fitted with two prototype acoustic receiver units designed to collect, interpret and store the information transmitted by the acoustic transmitter tags. Ten in each cage were also equipped with Data Storage Tags (DSTs) containing depth sensors to record individual-based datasets for comparison with the acoustically transmitted datasets. After compensation for sample loss caused by expected acoustic interference between the transmitter tags, the resulting dataset revealed that the receiver units collected 90–95% of the signals in both cages. Acoustic communication conditions in the sea-cages were not strongly impaired by factors such as fish density and local noise. Further, the dataset from the acoustic transmitters had comparable resolution and quality to that produced by the DSTs. However, acoustic tags provide data in real time and enable farmers to respond to the received information with farm management measures, whereas archival tags such as DSTs need to be retrieved and downloaded and hence have no real-time applications. We conclude that acoustic telemetry is feasible as a method to monitor the depth of fish in real-time commercial aquaculture.     

Spatial clustering of swine influenza in Ontario on the basis of herd-level disease status with different misclassification errors

This approach maximizes sensitivity of serology-based monitoring systems by considering spatial clustering of herds classified as false positive by herd testing, allowing outbreaks to be detected in an early phase. The primary objective of this study was to determine whether swine herds infected with influenza viruses cluster in space, and if so, where they cluster. The secondary objective was to investigate the combining of a multivariate spatial scan statistic with herd test results to maximize the sensitivity of the surveillance system for swine influenza. We tested for spatial clustering of swine influenza using the Cuzick–Edwards test as a global test. The location of the most likely spatial clusters of cases for each subtype and strain in a sample of 65 sow and 72 finisher herds in 2001 (Ontario, Canada), and 76 sow herds in 2003 (Ontario, Canada) was determined by a spatial scan statistic in a purely spatial Bernoulli model based on single and multiple datasets.

A case herd was defined by true herd-disease status for sow or finisher herds tested for H1N1, and by apparent herd-disease status for sow herds tested for two H3N2 strains (A/Swine/Colorado/1/77 (Sw/Col/77) and A/Swine/Texas/4199-2/98 (Sw/Tex/98)). In sow herds, there was no statistically significant clustering of H1N1 influenza after adjustment for pig-farm density. Similarly, spatial clustering was not found in finisher herds. In contrast, clustering of H3N2 Sw/Col/77 (prevalence ratio = 12.5) and H3N2 Sw/Tex/98 (prevalence ratio = 15) was identified in an area close to a region with documented isolation of avian influenza isolates from pigs.

For the H1N1 subtype tested by ELISA, we used an approach that minimized overall misclassification at the herd level. This could be more applicable for detecting clusters of positive farms when herd prevalence is moderate to high than when herd prevalence is low. For the H3N2 strains we used an approach that maximized herd-level sensitivity by minimizing the herd cut-off. This is useful in situations where prevalence of the pathogen is low. The results of applying a multivariate spatial scan statistic approach, led us to generate the hypothesis that an unknown variant of influenza of avian origin was circulating in swine herds close to an area where avian strains had previously been isolated from swine. Maximizing herd sensitivity and linking it with the spatial information can be of use for monitoring of pathogens that exhibit the potential for rapid antigenic change, which, consequently, might then lead to diminished cross-reactivity of routinely used assays and lower test sensitivity for the newly emerged variants. Veterinary authorities might incorporate this approach into animal disease surveillance programs that either substantiate freedom from disease, or are aimed at detecting early incursion of a pathogen, such as influenza virus, or both.     

A study of measurement of noninvasive blood pressure with the oscillometric device,Sentinel, in isoflurane‐anaesthetized horses

ObjectiveTo assess accuracy of noninvasive blood pressure (NIBP) measured by oscillometric device Sentinel compared to invasive blood pressure (IBP) in anaesthetized horses undergoing surgery. To assess if differences between the NIBP measured by the Sentinel and IBP are associated with recumbency, cuff placement, weight of the horse or acepromazine premedication and to describe usefulness of the Sentinel.Study designProspective study examining replicates of simultaneous NIBP and IBP measurements.AnimalsTwenty-nine horses.MethodsInvasive blood pressure was measured via a catheter in the facial artery, transverse facial artery or metatarsal artery. NIBP was measured using appropriate size cuffs placed on one of two metacarpal or metatarsal bones or the tail in random order. With both techniques systolic (SAP), mean (MAP), and diastolic (DAP) arterial blood pressures and heart rates (HR) were recorded. A mixed effects model compared the IBP to the NIBP values and assessed potential effects of catheter placement, localisation of the cuffs in combination with recumbency, weight of the horse or acepromazine premedication.ResultsNoninvasive blood pressure yielded higher measurements than IBP. Agreement varied with recumbency and cuff position. Estimated mean differences between the two methods decreased from SAP (lateral recumbency: range -5.3 to -56.0 mmHg; dorsal recumbency: range 0.8 to -20.7 mmHg), to MAP (lateral recumbency: range -1.8 to -19.0 mmHg; dorsal recumbency: range 13.9 to -16.4 mmHg) to DAP (lateral recumbency: range 0.5 to -6.6 mmHg; dorsal recumbency: range 21.0 to -15.5 mmHg). NIBP measurement was approximately two times more variable than IBP measurement. No significant difference between IBP and NIBP due to horse's weight or acepromazine premedication was found. In 227 of 1047 (21.7%) measurements the Sentinel did not deliver a result.Conclusion and clinical relevanceAccording to the high variability of NIBP compared to IBP, NIBP measurements as measured by the Sentinel in the manner described here are not considered as an appropriate alternative to IBP to measure blood pressure in anaesthetized horses.     

鄂西北(十堰)麦区小麦条锈病定点接种监测研究初报

[目的]探索湖北十堰麦区小麦条锈病冬繁区发展流行规律,使国家小麦主产区免受条锈病危害,保障全国夏粮增产丰收。[方法]采用高感小麦品种铭贤169结合人工接种的方法,在湖北十堰选取4个县市开展小麦条锈病定点接种和自然诱发监测试验。[结果]4个监测点接种后均发病扩展,未接种的自然诱发圃也显症发病;条锈病病菌冬季在十堰市辖区范围可以缓慢冬繁,潜育期随着海拔的升高潜伏期相应延长;早春阶段条锈病病菌在十堰市各县市可进行再侵染,但因气温低扩展缓慢,显症不明显。[结论]十堰市小麦条锈病春季菌源大部分为甘、陕及西南地区和本地冬繁的菌源。     

基于主被动遥感数据和面向对象的大蒜识别

针对开封市大蒜种植破碎化程度高,光学数据难以高精度、快速提取问题.该研究基于谷歌地球引擎(Google EarthEngine,GEE)云平台、随机森林算法(Random Forest,RF)和面向对象方法,选择融合Sentinel-1卫星的后向散射系数与Sentinel-2卫星的光谱、光谱指数及纹理特征,分别应用10...