National Agricultural Technology Extension and Service Center

Beijing, China

National Agricultural Technology Extension and Service Center

Beijing, China
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Liu Y.,Nanjing University of Information Science and Technology | Bao Y.X.,Nanjing University of Information Science and Technology | Wei W.,Ningxia Lightning Protection Technique Center | Lu M.H.,National Agricultural Technology Extension and Service Center | Liu W.C.,National Agricultural Technology Extension and Service Center
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

The brown planthopper, Nilaparvata lugens (Stål), is one of the most damaging pests affecting rice production in China. An outbreak of N. lugens can increase the incidence of disease and insect pest damage, both of which seriously affect the growth and the yield of rice. In order to analyze the influence of atmospheric dynamics, temperature, humidity, and other meteorological factors on the migration and density distribution of N. lugens over complex terrain, numerical simulations were performed. These simulations coupled the Flexpart model with the Weather Research and Forecast Model and the spatial analysis functions of GIS. These models and programs were used to simulate the N. lugens immigration and landing event that occurred at 6 plant protection stations, including Qujiang, Zhaoqing, Meixian in the Guangdong Province and Yichang in the Hubei Province, Ji’an in the Jiangxi Province, and Dongzhi in the Anhui Province, from September 30th to October 3rd in 2008 (BST). The simulation was in turn used to investigate the spatio-temporal distribution of the N. lugens’ landing and density patterns as they passed through the complex terrain of China. (1) The simulation of the reverse trajectory of the insects showed that the N. lugens at all three stations all originated from sites in the northwest. As the site of origin was in an area of complex terrain, the migration distances of the N. lugens were much shorter, and the direction was changeable and unpredictable. (2) According to the results of simulations of forward trajectories, if the mountains were low and were with a valley as channel for N. lugens’ migration, N. lugens could migrate along two mountainsides, lengthening their travel distance. If the mountains were high and there were no obvious valleys, migrating N. lugens could would directions and stay in their location of origin, because their route was blocked by the mountains. (3) When the slope of the mountains was steep, the density of the N. lugens was distributed along the mountains, because N. lugens could migrate along the mountain range. If the mountains consisted of multiple hills and peaks, N. lugens could pass through the areas of lower elevation, leading the density of N. lugens to be sporadically distributed. (4) The northeast wind allowed N. lugens to migrate further. Downdrafts coupled with high temperatures in this area, were conducive to N. lugens making landfall in higher densities. (5) To a certain extent, the result of the analysis of temperature distribution showed that N. lugens migrated towards warm areas. Ultimately, this led to the result that a higher density of N. lugens made landfall in warmer areas and along river valleys. In autumn, N. lugens landed in regions where the relative humidity was over 50%. There are some deviations from N. lugens’ immigration trajectories, azimuth angles, and differences between simulated results and actual observations. These results indicate that this simulation can considerably enhance the ability of various operations to forecast of the movements of migratory pests in China. In future, we plan to improve the spatial and temporal resolution of the observational data of N. lugens, which will allow us to achieve more robust simulated results. © 2016, Ecological Society of China. All rights reserved.


PubMed | Huazhong Agricultural University, National Agricultural Technology Extension and Service Center, French National Institute for Agricultural Research and University of Kentucky
Type: | Journal: Scientific reports | Year: 2015

Bactrocera dorsalis is one of the most economically important fruit flies around the world. In this study, 454 pyrosequencing was used to identify the bacteria associated with different developmental stages of B. dorsalis. At 97% nucleotide similarity, total reads could be assigned to 172 Operational Taxonomic Units belonging to six phyla. Proteobacteria dominated in immature stages while Firmicutes dominated in adult stages. The most abundant families were Enterococcaceae and Comamondaceae. The genus Comamonas was most abundant in pupae whereas completely absent in adults. Some identified species had low sequence similarity to reported species indicating the possibility of novel taxa. However, a majority sequence reads were similar to sequences previously identified to be associated with Bactrocera correcta, suggesting a characteristic microbial fauna for this insect genus. The type and abundance of different bacterial groups varied across the life stages of B. dorsalis. Selection pressure exerted by the host insect as a result of its habitat and diet choices could be the reason for the observed shift in the bacteria groups. These findings increase our understanding of the intricate symbiotic relationships between bacteria and B. dorsalis and provide clues to develop potential biocontrol techniques against this fruit fly.


Bao Y.X.,Nanjing University of Information Science and Technology | Sun M.Q.,Nanjing University of Information Science and Technology | Yan M.L.,Nanjing University of Information Science and Technology | Lu M.H.,National Agricultural Technology Extension and Service Center | Liu W.C.,National Agricultural Technology Extension and Service Center
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2016

Exotic prediction is an important content for predicting the occurrence of migratory pests. The simulations and prediction of the migration trajectory of pests is considered an ideal exotic prediction method that can reflect the spatio- temporal dynamics of the pest’s migration. The brown planthopper (BPH), Nilaparvata lugens (Stål), is an important migratory pest that affects rice production in China and the accurate forecasting of its migration trajectory can provide a scientific basis for the early warnings and effective prevention of pest-related catastrophes. In order to select appropriate pest migration trajectory models with good accuracy, high resolution, and easy popularization, we screened a great northward migration event of BPH that occurred in Hongjiang City of Hunan Province at the beginning of July in 2006, as a typical case of BPH migration in China. The Weather Research and Forecast (WRF) Model, a popular mesoscale weather research and forecast model used both at home and abroad, was used to simulate and output the atmospheric background fields in high resolution combined with re-analyzed meteorological data from the National Center of Environment Predicting of the USA (NCEP). The forecasting variable fields output by the WRF model as meteorological inputs to drive the two trajectory models were coupled with the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model and the Flexible Particle (FLEXPART) Dispersion Model to predict the migration trajectories and landfalling areas of BPH populations. According to the backward calculation results, the differences between some trajectory parameters of the two models, such as the pest sources, migration paths, migration heights, migrating speeds and migration distance, were compared. Finally, the observed data for the habitat, feeding conditions, and three-dimensional atmospheric airflow fields of BPH’s migration were used to verify the accuracy and precision of the simulations and calculations. The results suggest several important points. First, the two models show good consistent performance on the calculations of pest sources, migration paths (migration azimuth and flight direction), migration heights, migrating speeds and migration distance. However, the variations in the migration parameters in the FLEXPART model are larger than those in the WRF-HYSPLIT model. Second, as compared to HYSPLIT, the FLEXPART model can better represent the dynamical role of meso-scale weather especially convective processes in the migration processes such as takeoff, flying duration, and landing location, and more realistically simulate land surface processes, atmospheric turbulence structure, and undulating terrain and their impact on the migration of BPH populations. This is because the FLEXPART model has included more realistic parameterization schemes for convection, surface stress, and complex terrain in the trajectory calculations, whereas the HYSPLIT model does not. Third, the two models present reasonable simulations on pest sources, migration paths, and landfalling areas in terms of the selection of BPH populations for habitats and feeding conditions. However, the trajectories simulated by the FLEXPART model showed better agreement with the prevailing winds than the HYSPLIT model’s simulations. The evidence can be seen from the three-dimensional airflow fields in which the emigration, flight, and landfalling of BPH populations occurred. Fourth, both HYSPLIT and FLEXPART models demonstrated strong operational forecasting capabilities of migratory pest occurrence. © 2016, Ecological Society of China. All rights reserved.


Lv X.,China Agricultural University | Lv X.,CAS Institute of Zoology | Guo Y.,National Agricultural Technology Extension and Service Center | Shi D.,China Agricultural University
Reproductive Biology | Year: 2012

The effects of the two sterilants, quinestrol (QE) and levonorgestrel (LNG) on serum prolactin (PRL) level in lactating Mongolian gerbils and reproductive parameters of their offspring were examined in the study. Both sterilants increased the serum PRL level in lactating gerbils. The body weight as well as weights of the ovary, testis, epididymides, and seminal vesicles were lower, whereas that of the uterus was higher in the pups originating from QEtreated mothers in comparison to controls. Histological ovarian sections of the offspring from QE-treated mothers contained only growing follicles, whereas their uterine sections showed a thinner endometrium, thicker myometrium, and greater epithelial-cell height than in controls. The histometrical testis characteristics as well as sperm concentration and motility of male pups from QE-treated mothers were lower compared to those of the control group. The serum gonadotropin levels of female pups from mothers treated with QE were lower, whereas the serum estradiol (E2) and progesterone (P4) levels were higher than in control gerbils. In contrast, serum gonadotropin and testosterone (T) levels of male pups from QE-treated mothers were lower compared to controls. LNG did not affect the examined parameters of the offspring. The offspring from QE-treated mothers was infertile, whereas the offspring from LNG-treated mothers was fertile. In summary, QE and LNG have a stimulatory effect on PRL level in lactating gerbils. It also appears that QE administered via milk to mothers affects reproductive processes of their offspring. © 2012 Society for Biology of Reproduction & the Institute of Animal Reproduction and Food Research of Polish Academy of Sciences in Olsztyn.


Lv X.,China Agricultural University | Guo Y.,National Agricultural Technology Extension and Service Center | Shi D.,China Agricultural University
Theriogenology | Year: 2012

Quinestrol, a synthetic estrogen with marked estrogenic effects and prolonged activity, has potential as a contraceptive for Mongolian gerbils. The objective of this study was to describe the effects of quinestrol on reproductive hormone expression, secretion, and receptor levels in female Mongolian gerbils. Serum and pituitary concentrations of follicle stimulating hormone (FSH) and luteinizing hormone (LH) were decreased, whereas serum concentrations of estradiol (E2) and progesterone (P4) were increased after quinestrol treatment; the effects were both time- and dose-dependent. Furthermore, quinestrol downregulated expression of FSHβ and LHβ mRNA in the pituitary gland, as well as FSH receptor (FSHR) and estrogen receptor (ER) β in the ovary. However, it up-regulated mRNA expression levels of ERα and progesterone receptor (PR) in the pituitary gland and uterus, as well as mRNA for LH receptor (LHR) and PR in the ovary (these effects were time- and dose-dependent). In contrast, quinestrol had no significant effects on the mRNA expression levels of ERα in the ovary, or the gonadotropin α (GtHα) subunit in the pituitary gland. We inferred that quinestrol impaired synthesis and secretion of FSH and LH and that the predominant ER subtype in the pituitary gland of Mongolian gerbils may be ERα. Overall, quinestrol disrupted reproductive hormone receptor expression at the mRNA level in the pituitary-gonadal axis of the Mongolian gerbil. © 2012 Elsevier Inc.


Bao Y.X.,Nanjing University of Information Science and Technology | Cao Y.,Nanjing University of Information Science and Technology | Xie X.J.,Nanjing University of Information Science and Technology | Lu M.H.,National Agricultural Technology Extension and Service Center | And 3 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

Rice leaf roller, Cnaphalocrocis medinalis Guenee, is one of the most important crop pests in China due to its large area of occurrence, high frequency of outbreaks and serious damage to rice yields. In this paper, the lighting trap observational data of rice leaf rollers from 2000 to 2012 were analyzed to assess the impacts of atmospheric conditions on the migration and landfall of rice leaf roller. We have identified the main features of rice leaf roller's migration in the main rice-growing areas of China and presented a detailed analysis on a typical migration event occurred in late July, 2007 and verified the assessment result. By means of the Hybrid Single Particle Lagrangian Integrated Trojectory Model for Version 4.0 (HYSPLIT-4), a software of calculating particle trajectory in the air, the backward migration trajectories of the rice leaf roller landfalled the rice growing regions in the the Yangtze River Valley were calculated and the Weather Research and Forecast model (WRF) 's simulations on the atmospheric backgrounds in this event combined with the reanalysis data of the National Ceter of Environmental Predicting (NCEP) were used to assess the impacts of weather conditions on the catastrophic migrations of rice leaf roller. Several important findings are obtained from this study. First, during the studying period from 2000 to 2012, the migration of rice leaf roller started at the beginning of March in a year, the period during March to August was the period of prevailing migration northward in which the populations immigrate into the south China, the southwest China, the regions between the Nanling Mountain and the Yangtze River and the valley regions between the Yangtze River and the Huaihe River in China successively and emerge a series of immigration peaks. During the period from September to November each year, the southward migration is the reversed processes in the above regions. The rice leaf roller migrated backward to the valley region between the Yangtze River and the Huaihe River, the regions between the Nanling Mountain and the Yangtze River and South China in turn. Second, the backward trajectories calculations of rice leaf roller's migration northward included the beginning and re-emigrating populations in the selected event indicated that the sources of the rice leaf roller's populations were situated at the southwest parts of the landfall regions and the migration altitudes varied from 550 m to 850 m above ground level. As a comparison, the migrating trajectories in the coastal regions were more complicated than the other regions. Third, the horizontal wind is the main driving force for the long-distance migration of rice leaf roller's populations and the prevailing southerly at 925 hPa height is favorable for the migration northward. Three-dimensional windfield, especially the strong vertical airstream plays a dominant role in the up and down of the migration heights. Fourth, the downward flow and rainfall are the two key dynamic factors for the landfall of the rice leaf rollers. Fifth, as a kind of hygrotaxis pest, the suitable atmospheric moisture condition is beneficial to the long-distance migration and landfalling of rice leaf roller's populations. In this event, most of the rice leaf rollers landfalled in the areas of the relative humidity higher than 75%. © 2015, Ecological Society of China. All rights reserved.


Yang F.,National Agricultural Technology Extension and Service Center | Dong Y.,National Agricultural Technology Extension and Service Center | Xu M.-G.,Chinese Academy of Agricultural Sciences | Bao Y.-X.,Chinese Academy of Agricultural Sciences
Chinese Journal of Applied Ecology | Year: 2012

Based on the data from 94 experiments of straw returning in Anhui, Jiangxi, Hunan, Hubei, Guangxi, Sichuan, and Chongqing, and by using mathematic modeling approach, this paper evaluated the effects of straw returning on the soil fertility and crop yield in southern China. Obvious regional differences were observed in the soil fertility index (SFI) and crop yield response. In study area, the croplands with the SFI of Grade III and Grade IV were predominant, occupying 69.1% and 21.3% of the total, respectively. Averagely, straw returning increased the SFI and crop yield by 6.8% and 4.4%, respectively, as compared with the control (no straw returning). The SFI was significantly linearly correlated with rice yield, and could well reflect the integrated soil fertility in study area. At present, straw returning with decomposing agent added is one of the most important measures to improve the integrated soil fertility in southern China, which should be widely popularized.


Bao Y.X.,Nanjing University of Information Science and Technology | Huang J.Y.,Nanjing University of Information Science and Technology | Xie X.J.,Nanjing University of Information Science and Technology | Lu M.H.,National Agricultural Technology Extension and Service Center
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2013

Based on the daily reanalyzed meteorological dataset of the National Center of Environment Predicting (NCEP) in USA and the pentadly lighting catches of brown planthoppers (BPH) in China, in this paper, the temporal and spatial relationship between the selected monsoon index and the immigrations of BPH was investigated to explore the influence of monsoon advancing, retreating and conversion on the immigrations of BPH in China. The results showed as follows: (1) The middle ten days and the last ten days of March in a year is a conversing period from the north monsoon to southwest monsoon and the first large-scale migration northward of BPH's populations occurs in the first ten days of April after the beginning of the southwest monsoon. The main landing regions of BPH's populations in this large-scale migration northward are the rice-growing regions in the South and the Southwestern China. Then, the BPH's populations migrate to the other northern parts subsequently. (2) From the middle ten days of June to the middle ten days of August in a year, the south monsoon index reach its maximum of the positive values while the migrations northward of BPH occur most frequently, the populations land in the all four main rice-growing regions, the peaks and landing heads of BPH's immigration northward amount to the summit. (3) From the last ten days period of August to the middle ten days of September in a year is a conversing period from the south monsoon to the north monsoon and it is the ending period of BPH's immigration northward and the beginning period of the immigration southward. The first large-scale migration southward of BPH' s populations occurs in this period and the main landing regions are the rice-growing regions between the Yangtze River and the Huaihe River and the rice-growing regions between the Yangtze River and the Nanling Mountain. (4) From the last ten days of September to the middle ten days of October is the strengthening period of the north monsoon and the weakening period of the south monsoon and it is the peak period of BPH's immigration southward of all rice-growing regions. (5) In the last tendays of October, the south monsoon begins the evacuating from the mainland of China and the north monsoon begins controlling the mainland and the ending dates of BPH's immigrations appear in each rice-growing region successively from north to south. (6) In the years of BPH's abnormal occurrence, the sooner or later advancing northward of the southwest monsoon decided on the beginning dates of BPH's immigration and the expanding southward some time or later of the north monsoon determined the ending dates of BPH's immigration coming earlier or later. (7) The beginning date of BPH'simmigration falled behind the change of the southwest monsoon and the ending date of immigration lagged behind the change of the north monsoon and their delaying times were 5 to 15 days.


Bao Y.-X.,Nanjing University of Information Science and Technology | Ding W.-W.,Nanjing University of Information Science and Technology | Xie X.-J.,Nanjing University of Information Science and Technology | Lan P.,Nanjing University of Information Science and Technology | Lu M.-H.,National Agricultural Technology Extension and Service Center
Journal of Tropical Meteorology | Year: 2014

In order to clarify the statistical pattern by which landfalling strong tropical cyclones (LSTCs) influenced the catastrophic migrations of rice brown planthopper (BPH), Nilaparvata lugens (stål) in China, the data of the LSTCs in China and the lighting catches of BPH that covered the main Chinese rice-growing regions from 1979 to 2008 were collected and analyzed in this work with the assistance of ArcGIS9.3, a software of geographic information system. The results were as follows: (1) In China, there were 220 strong tropical cyclones that passed the main rice-growing regions and 466 great events of BPH's immigration in the 30 years from 1979 to 2008. 73 of them resulted in the occurrence of BPH's catastrphic migration (CM) events directly and 147 of them produced indirect effect on the migrations. (2) The number of the LSTCs was variable in different years during 1979 to 2008 and their influence was not the same in the BPH's northward and southward migrations in the years. In the 30 years, the LSTCs brought more obvious influence on the migrations in 1980, 1981, 2005, 2006 and 2007. The influence was the most obvious in 2007 and all of the 7 LSTCs produced remarkable impact on the CMs of BPH's populations. The effect of the LSTCs on the northward immigration of BPH's populations was the most serious in 2006 and the influence on the southward immigration was the most remarkable in 2005. (3) In these years, the most of LSTCs occurred in July, August and September and great events of BPH's immigration occurred most frequently in the same months. The LSTCs played a more important role on the CM of BPH's populations in the three months than in other months. (4) The analysis on the spatial distribution of the LSTCs and BPH's immigration events for the different provinces showed that the BPH's migrations in the main rice-growing regions of the Southeastern China were influenced by the LSTCs and the impact was different with the change of their spatial probability distribution during their passages. The most serious influence of the LSTCs on the BPH's migrations occurred in Guangdong and Fujian provinces. (5)The statistical results indicated that a suitable insect source is an indispensable condition of the CMs of BPH when a LSTC influenced a rice-growing region.


PubMed | National Agricultural Technology Extension and Service Center
Type: Journal Article | Journal: Ying yong sheng tai xue bao = The journal of applied ecology | Year: 2013

Based on the data from 94 experiments of straw returning in Anhui, Jiangxi, Hunan, Hubei, Guangxi, Sichuan, and Chongqing, and by using mathematic modeling approach, this paper evaluated the effects of straw returning on the soil fertility and crop yield in southern China. Obvious regional differences were observed in the soil fertility index (SFI) and crop yield response. In study area, the croplands with the SFI of Grade III and Grade IV were predominant, occupying 69.1% and 21.3% of the total, respectively. Averagely, straw returning increased the SFI and crop yield by 6.8% and 4.4%, respectively, as compared with the control (no straw returning). The SFI was significantly linearly correlated with rice yield, and could well reflect the integrated soil fertility in study area. At present, straw returning with decomposing agent added is one of the most important measures to improve the integrated soil fertility in southern China, which should be widely popularized.

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