面向现代化的农村住宅集约建设研究

分析了农村住宅集约建设对社会主义新农村建设的意义,剖析了农村住宅集约建设对农村现代化的影响,概括了我国农村住宅管理的现状和问题,在此基础上构建了面向现代化的农村住宅集约开发模式,以此推动新农村建设事业的发展.     

Modeling of Shoot Elongation and Leaf Appearance in Potted Mulberry

Summary

To predict mulberry growth, modeling of shoot elongation and leaf appearance of potted mulberries was attempted. Potted mulberries were grown in temperature-controlled phytotrons. Changes in the rates of mulberry shoot elongation and leaf appearance, and the relationship between the rates and temperature were investigated. The rate of shoot elongation increased until the shoot length reached about 100cm, and became stable thereafter. The rates of both shoot elongation and leaf appearance increased with the increase in temperature from 15°C to 27°C, but not at higher temperatures. However, the rate of leaf appearance increased with the rise in temperature up to 31°C. On the basis of these results, the shoot elongation and leaf appearance of mulberry in phytotron were simulated in non -linear regression models. The relationship between the rate of shoot elongation and temperature, and the rate of leaf appearance and temperature in the model fitted to measured values very well, and that between the rate of shoot elongation and shoot length in the models tended to be in accordance with the measured values. Shoot length and leaf number predicted by the model were in concurrence with the measured values.     

基于小波分解的凡纳滨对虾养殖水体水质的仿真研究

依据凡纳滨对虾养殖水体中测定的水质数据,利用ARMA 模型和神经网络模型两种方法对水质动态进行预测和分 析,提出了一种基于小波分解且针对凡纳滨对虾养殖水体水质预测的ARMA 模型,且ARMA（p,q）模型中的p 值和q 值分别为4和2。预测结果表明,所建立的预测模型精度较高。将ARMA 模型预测的结果与神经网络预测的结果进行了对比后发现,基于小波分解的ARMA 模型对对虾养殖水体水质预测的有效性和准确性优于神经网络预测模型。     

Veröffentliehungen: Von Professor Dr. rer. nat. habil. Werner Selke

Model field experiments were carried out on orthic Luvisols soil in the years 1987, 1988 and 1989, in which winter wheat was fertilized with 15N‐ammonium nitrate in spring. Nitrogen was applied three times at rates of 40 kg N per ha at the beginning of vegetative growth, shooting and heading. The distribution of labelled fertilizer to plants and soil was traced in two successive samplings. The 15N‐uptake by wheat tops reached 45–50% for each rate of application, but in the dry year it was retarded. The residual fertilizer N in the soil was found in the upper layer 0–15 cm as fresh immobilized organic N. The lower soil layer 15–60 cm contents traces only from the labelled nitrate. Leaching of spring‐applied low fertilizer rates for cereals within the growth season is of minor importance, except in springs with early high rainfalls.     

干湿交替过程对黄土高原几种主要土壤钾有效性的影响

室内模拟试验研究不同温度条件下干湿交替对黄土高原区四种土壤有效钾的影响,结果表明:(1)土壤钾有效性受干湿交替过程影响较大,干湿交替次数与有效钾含量间具有y=a+blogx函数关系;(2)温度升高,增强了干湿交替的剧烈程度,提高土壤钾的固定量,显著降低了土壤钾的有效性;(3)建立了反映干湿交替次数、土壤物理性粘粒和粘粒含量比值、以及钾固定量三者之间的关系方程。     

耕地资源管理信息系统下节水灌溉模型建立的初步构想

通过对区域节水规划、水文地质、水利工程、气候、土壤、作物、区域生态、经济及社会发展状况的研究,在耕地资源管理信息系统下建立相对独立完整又密切相关的符合区域水分管理和农业生产实际的节水灌溉专家咨询决策系统和模型,并结合及时必要的数据更新与扩充,从而实现区域农业灌溉的宏观调控、最佳灌溉的预测预报、实现节水知识的技术咨询、耕地资源水肥气热计算机管理、节水灌溉与作物布局、结构调整、现代化管理的同步发展。     

基于模型和GIS的江苏省农田土壤有机碳变化研究

 以土壤基本性状、气候条件、作物产量和耕作措施等为基本输入数据 ,将土壤有机碳分解模型与GIS技术耦合 ,模拟江苏省农田土壤有机碳含量分布的现状及未来变化趋势。对典型农区土壤有机碳测定数据的验证表明 ,所采用的模型能较好地描述土壤有机碳的动态变化。模拟结果指出 ,自第二次土壤普查以来 ,全省 77%的农田土壤有机碳含量有所增加。至 2 0 0 0年 ,苏北和沿海地区土壤有机碳含量增加量为 1.0～ 3.0g·kg-1,苏南太湖地区增加量为 3.5～ 5 .0g·kg-1。但苏中的江淮平原和宁镇丘陵区略有下降 ,仅增加约 0 .5～ 1.5g·kg-1。预测 2 0 10年在不同秸秆还田量条件下 ,江苏省农田土壤有机碳含量将继续增加 ,且有较大的接纳外源有机碳的能力     

Comparative study of flow field and drag coefficient of model and small natural trees in a wind tunnel

The influence of trees in urban areas is typically assessed using urban microclimate models. These models rely on wind tunnel experiments using small-scale tree models to verify and validate their predictions of the flow field. However, it is not known sufficiently to which extent small model trees used in wind tunnel studies can recreate the behavior of large trees found in cities. In the present study, the drag coefficient and the turbulent flow downstream of model trees are compared with the ones of natural trees of a similar size to determine whether both types of tree provide similar aerodynamic characteristics. Therefore, measurements of the drag force and the flow field, using particle image velocimetry, are performed. The aerodynamic characteristics of the small trees are compared with the ones measured on larger mature trees from previous studies. The present study shows that the drag coefficients of model and natural trees are similar only if both types have a similar aerodynamic porosity and if the model tree can undergo an aerodynamic reconfiguration similar to that of a natural tree. Such reconfiguration implies the reorientation of the branches and leaves due to wind. A study on the influence of seasonal foliar density variation shows that the foliage configuration plays a critical role on the drag coefficient and the flow field. A defoliated tree, such as a deciduous tree in winter, is shown to have a substantially lower drag coefficient and a negligible influence on the flow.     

2008年安徽雪深全国之最的成因探讨

基于大气探测资料和雪灾评估报告,分析2008年雪情分布状况,得出安徽雪深为全国最大的事实,并从天气学、数值模式模拟方面探讨安徽雪深之最的原因。结果表明:①2008年安徽雪深较大的区域集中在大别山和江淮之间,该区域为全国积雪深度之最。②西南暖湿气流北上,北方阻塞系统稳定存在,冷暖空气在长江中下游不断交汇,水汽凝结易形成雨雪天气。水汽输送和相对湿度很大,非常有利于在安徽形成较大降雪天气。③雪、冻雨的天气学分析说明,长江以北地区易形成降雪,江南地区则易形成冻雨。④短波槽长期稳定维持在安徽附近地区,成为安徽省积雪深度最大的理由之一。⑤MM5模式模拟结果验证淮河以南地区降水较大,江南地区的降水表现为冻雨,江北地区则表现为降雪。     

Capability of the ‘Ball-Berry’ model for predicting stomatal conductance and water use efficiency of potato leaves under different irrigation regimes

The capability of the ‘Ball-Berry’ model (BB-model) in predicting stomatal conductance (g_s) and water use efficiency (WUE) of potato (Solanum tuberosum L.) leaves under different irrigation regimes was tested using data from two independent pot experiments in 2004 and 2007. Data obtained from 2004 was used for model parameterization, where measurements of midday leaf gas exchange of potted potatoes were done during progressive soil drying for 2 weeks at tuber initiation and earlier bulking stages. The measured photosynthetic rate (A_n) was used as an input for the model. To account for the effects of soil water deficits on g_s, a simple equation modifying the slope (m) based on the mean soil water potential (Ψ_s) in the soil columns was incorporated into the original BB-model. Compared with the original BB-model, the modified BB-model showed better predictability for both g_s and WUE of potato leaves on the parameterization data set. The models were then tested using the data from 2007 where plants were subjected to four irrigation regimes: non-irrigation (NI), full irrigation (FI), partial root-zone drying (PRD), and deficit irrigation (DI) for 3 weeks during tuber initiation and earlier bulking stages. The simulation results showed that the modified BB-model better simulated g_s for the NI and DI treatments than the original BB-model, whilst the two models performed equally well for predicting g_s of the FI and PRD treatments. Although both models had poor predictability for WUE (0.47 < r² < 0.71) of potato leaves, the modified BB-model was able to distinguish the effects of the irrigation regimes on WUE being that the WUE was generally greater for PRD than for FI and DI plants. Conclusively, the modified BB-model is capable of predicting g_s and of accounting for the differential effects of irrigation regimes on WUE of potato leaves. This information is valuable for further simulating potato water use thereby optimizing WUE under field conditions.