Yin W.-D.,Chinese Academy of Agricultural Sciences |
Qiu G.-S.,Chinese Academy of Agricultural Sciences |
Yan W.-T.,Chinese Academy of Agricultural Sciences |
Sun L.-N.,Chinese Academy of Agricultural Sciences |
And 3 more authors.
Journal of Economic Entomology | Year: 2013
To understand the influence of different apple varieties on the development and reproduction of the European red mite, Panonychus ulmi (Koch) (Acari: Tetranychidae), age-stage two-sex life tables of P. ulmi on 'Fuji,' 'Starkrimson Delicious,' 'Golden Delicious,' and 'Granny Smith' varieties were constructed under laboratory conditions at 23 ± 1°C, 75 ± 5% relative humidity, and a photoperiod of 16:8 (L:D) h. Results showed that total development time of immature females was shorter on Fuji than on the other varieties, and this was because of its shorter egg duration. Immature survival of P. ulmi was 74.51-78.00% among four apple varieties, and no significant differences were found. The total fecundity per female was significantly higher on Golden Delicious (34.12 eggs per female) than that on Fuji (27.15 eggs per female), Starkrimson Delicious (25.15 eggs per female), and Granny Smith (20.62 eggs per female). Based on the intrinsic rate of population increase, Fuji and Golden Delicious were more suitable than Starkrimson Delicious and Granny Smith. © 2013 Entomological Society of America.
Xu T.,CAS Institute of Remote Sensing |
Xu T.,University of Chinese Academy of Sciences |
Liao J.-J.,CAS Institute of Remote Sensing |
Shen G.-Z.,CAS Institute of Remote Sensing |
And 5 more authors.
Hongwai Yu Haomibo Xuebao/Journal of Infrared and Millimeter Waves | Year: 2016
Leaf area index (LAI) is an important indicator of wetland ecosystem health. Poyang Lake wetland vegetations grow densely, with LAI of large dynamic range. Considering the complex scattering mechanisms of radar data, a radar vegetation index was defined. To overcome the saturation of the optical vegetation indices, a new integrated vegetation index using GF-1 and Radarsat-2 data was established for estimation of wetland vegetation LAI. The validation of measured data and theoretical model simulation showed that this integrated vegetation index is a good alternative to that using only the optical or radar observation. The best fitting models were built with optical vegetation indices, radar vegetation index, and the integrated vegetation index, respectively. The result indicates that the integrated vegetation index can improve predication accuracy for wetland vegetation LAI. © 2016, Chinese Optical Society. All right reserved.
Zhang Z.-Y.,Hohai University |
Wang S.-F.,North China University of Water Conservancy and Electric Power |
Duan A.-W.,Farmland Irrigation Research Institute |
Wang B.,Hohai University
Shuikexue Jinzhan/Advances in Water Science | Year: 2010
A reference evapotranspiration(ET 0) prediction model is developed based on the least squares support vector machines. Weather forecasts are used for ET 0 predictions. The model can be trained with daily weather parameters including quantified weather types and wind grades, etc. Different combinations of daily weather parameters can be tested in the model training processes. In this study, the daily weather parameters are obtained from the Guangli irrigation district during the period 1997-2007. The 1997-2006 data are used for the model training, and a total of 10 daily ET 0 forecasting schemes are established. Predictions of daily ET 0 using each of the 10 schemes are validated with the observations from 2007. The results show that the scheme using the air temperature and the quantified weather types and wind grades as model predictors is able to give the best model performance; and the corresponding statistics are the root mean square error(E RMS) of 0.5182, the relative error(E R) of 0.1878, the coefficient of determination(R 2) of 0.8648, the I A of 0.9669, and the regression coefficient(R C) of 0.9868. Acceptable daily ET 0 predictions are also obtained with other 6 schemes, among which the simplest scheme using only the air temperature as the model predictor can also produce fair results as revealed by E RMS=0.6576, E 2=0.2332, R 2=0.9866, I A=0.7747 and R C=0.9680. The latter scheme shows a strong potential in practical applications.
Water velocity at water-air interface is not zero: Comment on "Three-dimensional quantification of soil hydraulic properties using X-ray computed tomography and image-based modeling" by Saoirse R. Tracy et al.
Zhang X.X.,Farmland Irrigation Research Institute |
Fan X.Y.,Chinese Academy of Agricultural Sciences |
Li Z.Y.,Chinese Academy of Agricultural Sciences
Water Resources Research | Year: 2016
Tracy et al. (2015, doi: 10.1002/2014WR016020) assumed in their recent paper that water velocity at the water-air interface is zero in their pore-scale simulations of water flow in 3-D soil images acquired using X-ray computed tomography. We comment that such a treatment is physically wrong, and explain that it is the water-velocity gradient in the direction normal to the water-air interface, rather than the water velocity, that should be assumed to be zero at the water-air interface if one needs to decouple the water flow and the air flow. We analyze the potential errors caused by incorrectly taking water velocity at the water-air interface zero based on two simple examples, and conclude that it is not physically sound to make such a presumption because its associated errors are unpredictable. © 2016. American Geophysical Union. All Rights Reserved.
Wang K.,Wuhan University |
Zhang J.,Farmland Irrigation Research Institute
5th International Conference on Bioinformatics and Biomedical Engineering, iCBBE 2011 | Year: 2011
The objective of this study was to investigate chemical contaminants penetrated into groundwater through macropores in the vazone zone. A total of 4 experiments with various ponding depths were conducted. With a combined method, dye and iodine-starch staining were used to visualize soil macropore and soil water flow patterns, respectively. Flow patterns with a low infiltration amount were similar to the macropore patterns and macropores were the main factor to control the flow patterns. As the infiltration amount increased, flow patterns were influenced by both macropores and boundary conditions. Soil water flow patterns became more heterogeneous as the heterogeneity of macropores increased. Stained patterns played a much important role in redistribution of infiltration water than the soil saturation change in the stained region. The contaminants concentration decreased dramatically in the upper depth and then the decreasing trend was slowed down. © 2011 IEEE.