Effect of Seedling Raising Methods on Leaf Photosynthesis and Grain Yield of Mechanically-transplanted Japonica Rice

This study was conducted to investigate the effects of seedling raising modes on photosynthetic charactedsticsand grain yield under wheat straw returning. Four representative cultivars in Huaibei area were selected as test materials. By setting potted seedlings and carpet seedlings, the effects of different nursery meth- ods on the photosynthesis of rice at different growth stages in Huaibei area were investigated. Compared with carpet seedlings, the leaf area index of potted seedlings decreased at the maturation stage, but the dry weight of leaf shewed no significant difference.The SPAD of potted seedlings had an increasing trend after transplanting, but the SPAD increased differently according to cultivars. The net photosynthetic rate, stomatal conductance and transpiration rate of the leaves of pot seeding rice were significantly higher than those of carpet seedling rice on the 85^th d after transplanting. However, theintracellular CO2 concentration and water use efficiency of leaves had no significant differences between different ＇treatments. The results indicate that the photosynthetic capacity of flag leaves of pot seedling rice is stronger in early and middle stages, but the decay rate of photosynthetic function is slightly faster than carpet seedling rice, which might be the main reason for the rice yield of potted seedlings having no remarkable difference from carpet seedlings.

A method for raising brown planthopper (BPH), Nila-parvata lugens (Stl)

To get mass ppoulation of the BPH, agood method for rasing BPH isneeded. In this paper, a convenientmethod was recommended.BPH population used in the ex-periment was provided by Jiangsu A-cad of Agri Sci. Six raising BPHmethods, i. e, with rice buds (RB),rice seedling (RS), seedling soillesscultured (SSC), mature rice (MR),and rice stem cultured in nutrient

Effective stress analysis method of seismic response for high tailings dam

Based on the analysis method for tailings dam in upstream raising method presently used in metallurgy and nonferrous metals tailings depository in the world, an effective stress analysis method of seismic response for high tailings dam was developed according to the results of engineering geological exploration, static and dynamic test and stability analysis on Baizhishan tailing dam 113.5 m high. The law of generation, diffusion and dissipation of seismic pore water pressure during and after earthquake was investigated, and the results of tailings dam’s acceleration, seismic dynamic stress and pore water pressure were obtained. The results show that the seismic stability and liquefaction resistance of high tailings dam are strengthened remarkably, and the scope and depth of liquefaction area at the top of dam are reduced greatly. The interior stress is compressive stress, the stress level of every element is less than 1.0 and the safety coefficient of every element is greater than 1.0. The safety coefficient against liquefaction of every element of tailing dam is greater than 1.5 according to the effective stress analysis of seismic response by finite element method. The calculated results prove that liquefaction is the main reason of seismic failure of high tailing dams, and the effect of seismic inertia forces on high tailing dams’ stability during earthquake is secondary reason.

The Comparison of the Control Effect on the Varroa Mite with Different Ways of Raising Management

[Objective] The aim was to o research the control effect to Varroa destructor and Tropilaeplaps clareae whit new raising management methods, and reduce the pollution caused by drug treatment of bee. [ Metkod] We took the method that was replace the hive and comb on test col- onies with the comb Formalin soaking liquid used three days after the dry and sterilization in advance with the hive. The test groups were 10 colonies randomly selected from the disinfected comb in the breeding. This was the first kind of method. The control groups were 10 colonies randomly se- lected by the conventional breeding management methods. From January 20th, statistic analysis on parasitic situation of bees once every month be- tween the two methods, and take corresponding measures to prevent and control the varroa mite according to the varroa mite parasitic number in time, then the control effect of mite between the two methods were compared with. [ Result] The results showed that the first method was better than the second one in V. destructor, the control time of T. clareae delayed about one month [ Conclusion] Good breeding method could restrain I V. destructor and T. clareae parasitism, speeded up the colony development, and reduced the pollution of chemical drugs on bee products, regar- dod as a kind good method of controlling bee mites to make use of the feeding and management technology.

A new technique of combining accretion by cyclone separator and scattertube for tailings dams

A new technique of combining accretion by cyclone separator and scattertube for tailings dams was developed according to laboratory experiment, model experiment and spot experiment technology. Three tailings dams were successfully constructed by the new technique. The results of engineering geological exploration, static and dynamic test and stability analysis on Baizhishan tailings dams prove that the new technique improves structure and stability of the dams and working conditions compared with the traditional technique. The thin layers of fine-grained soils are greatly reduced, fine tailings sand is solid to make the dam stable and seepage conditions are well improved; the immersing line of the dam descends. In addition, the stability and liquefaction resistance of tailings dams are strengthened remarkably. The interior stress is compressive stress, stress level of every element is less than 1.0 and safety coefficient of every element is greater than 1.0. The safety coefficient against liquefaction of every element of tailings dams is greater than 1.5 according to the analysis of seismic response by finite element method.

Effects of soilless substrates on seedling quality and the growth of transplanted super japonica rice

This study was conducted to investigate the effects of soilless substrates of hydroponically grown long-mat seedlings （HLMS） on seedling quality and field growth characteristics of transplanted super japonica rice. A widely grown conventional super japonica rice cultivar （Wuyunjing 23） was selected as the test material. The effect of HLMS on seedling quality, mechanical transplantation quality, field growth characteristics, yield, and benefit-cost ratio were compared with seedlings grown in organic substrates and traditional nutritive soil, whJch was selected as the control. Root number, root twJstJng power and root activity of seedlings cultivated by HLMS were decreased compared to that of the organic substrates andcontrol. However, seedling root length as well as aboveground growth were increased compared to the organic substrates and control seed- lings. In the HLMS, the content of gibberellin acid （GA3） decreased while abscisic acid （ABA） content increased compared to that of the organic substrates and control seedlings. During the early stages after transplanting, the re-greening of HLMS was delayed compared to that of the organic substrates and control seedlings. Nevertheless, there were no significant differences in tiller dynamics and crop yield among the HLMS, organic substrates and control treatments. The effects of HLMS on seedling production were similar to those of the organic substrates and traditional nutritive soil in the present study, suggesting that HLMS have the potential to replace traditional nutritive soil in seedling production without decreasing crop yield. Finally, it is important to reduce organic substrates and topsoil dependence during rice seedling production and worthwhile to consider HLMS popularization and its application on a larger scale.

A RAISED PANEL METHOD BASED ON NURBS FOR FREE-SURFACE POTENTIAL FLOWS WITH FORWARD SPEED

A raised panel method based on NURBS (Non-Uniform Rational B-Splines) forfree-surface flows with forward speed is presented. In this generalized panel method, NURBS areemployed to represent the body geometry, disturbed free surface, and to express the unknown sourcestrength distribution, on the body surface and above the free surface. Compared with commonhigher-order panel methods, it has no need of adopting local coordinates. NURBS make the geometryrepresentation of the body shape and the wave pattern more precise. Raised panels above the freesurface produce less numerical dispersion error, need less CPU consumption and are helpful andcombined with collocation-point shifting up-stream, can satisfy the radiation condition numerically.By using continuous and discrete Fourier analysis, numerical errors of this method are discussedand a general expression for the errors of numerical damping and dispersion, including the effectsof the vertical distance of singularities to the free surface, the order of singularity distributionrepresented by B-splines in panels, and collocation-point shifting is derived.