日光温室中油桃的整形修剪

温室内栽植早红2号油桃,在温室中后部宜选用树体较高的小冠自由纺锤形,前部宜选用三主枝(或二主枝)小冠无侧枝开心形,群体呈南低北高、一面坡式排列。冬剪后枝端距以10～15cm为宜,新梢适宜摘心长度为30cm,采果后重缩剪控冠更新效果好。     

Bayesian spatiotemporal modelling analysis of hemorrhagic fever with renal syndrome outbreaks in China using R-INLA

Hemorrhagic fever with renal syndrome (HFRS) is a category B infectious disease caused by Hantavirus infection, which can cause acute kidney injury and has a high mortality rate. At present, China is the country most severely afflicted by HFRS in the world, and it is critical to carry out efficient HFRS prevention and management in a scientific and accurate manner. The study used data on the incidence of HFRS in mainland China from 2015 to 2018, built a Bayesian hierarchical spatiotemporal distribution model, and applied the Integrated Nested Laplace Approximation algorithm to analyse the factors influencing the development of HFRS, the spatial and temporal distribution characteristics, and the threshold exceedance locations. The results revealed that the woodland and grassland area (RR = 1.357, 95% CI: 1.005–1.791), economic level (RR = 1.299, 95% CI: 1.007–1.649), and traffic level (RR = 2.442, 95% CI: 1.825–3.199) were all significantly and positively associated with the development of HFRS, with traffic level having the strongest promoting effect. The seasonal cycle was obvious in time, with peaks in May–June and October–December each year, most notably in November. Spatially, there was a south-heavy north-light trend, with a high risk of incidence largely in places rich in mountain and forest vegetation, of which Guizhou, Guangxi, Guangdong, and Jiangxi provinces continuing to have a high incidence in recent years, and the evolution of the epidemic in Hubei and Hunan was becoming more serious. When the early warning threshold was set at 0.2, the detection impact was best, and Guizhou, Guangxi, Guangdong, Jiangxi, Hainan, and Tianjin were positioned near the critical point of the exceedance threshold with the highest risk of incidence. It is recommended that the relevant managers call for active vaccination of outdoor workers, such as those working in agriculture and construction sites, implement rat prevention and extermination before winter arrives, and warn high-risk and medium-high-risk areas to conduct early outbreak surveillance. Move the prevention and control gates forward based on the exceedance threshold for doing preventive and control detection and epidemic research and judgement work.     

呼伦贝尔草甸草原不同显热通量观测方法比较

显热通量（sensible heat flux，H）是反映地表湍流运动的重要参数，准确获取该参数对于区域内热量交换规律的认识和农业生产及水资源的有效管理具有重要意义。涡动相关仪（eddy covariance system，EC）和大孔径闪烁仪（large aperture scintillometer，LAS）是目前生态系统水热通量的主要测量手段，但两者观测范围的空间尺度存在差异。该研究以呼伦贝尔草甸草原生态系统为对象，通过对比分析两种方法观测的显热通量（H_LAS和H_EC）变化特征，对两者之间的差异（ΔH）及产生原因进行探究，并且定量研究了不同因子对ΔH的影响程度。结果表明，在不同时间尺度内，H_LAS和H_EC的变化趋势基本一致，显热通量主要受到净辐射的驱动作用，同时ΔH与净辐射存在正相关性；对应时刻H_LAS和H_EC之间线性回归方程斜率为1.13，拟合优度R²为0.81，说明大孔径闪烁仪在草甸草原区有着很好的适用性；EC能量平衡闭合程度会影响H_LAS和H_EC之间差异，剔除能量平衡闭合率（energy balance ratio，EBR）小于0.8的数据后，H_LAS和H_EC之间线性回归方程斜率减小至1.05，说明能量平衡闭合程度越高ΔH越小；净辐射（net radiation，R_n）、风速（wind speed，WS）、波文比（Bowen ratio，Bowen）和饱和水汽压差（saturated water vapor pressure difference，VPD）与ΔH之间相关性显著，是ΔH的主要气象环境因子；ΔH单个影响因子的解释能力从高到低依次为净辐射、风速、EC能量平衡闭合率、饱和水汽压差、波文比，任意两个不同影响因子之间均呈现双因子增强作用，解释能力较高的交互影响因子为净辐射/风速和风速/波文比。研究结果有利于准确理解LAS与EC显热通量观测过程中的空间尺度效应，同时可为区域尺度扩展和遥感地面验证过程中通量数据的质量控制提供科学参考依据。