For the problems in the operation of farm machinery, such as information lag, poor timeliness, and lack of effective means of scheduling farm machineries etc, a farm machinery monitoring and scheduling system based on GPS, GPRS and GIS is designed and implemented. The system consists of two parts, which are the onboard terminal based on PDA and the farm machinery monitoring and scheduling center. The former integrated with GPS Receiver, sensors and MapX mobile GIS components can realize fast collection and real-time display of farm machinery information, and send such real-time data to the data-processing server via GPRS. Based on MapObjects GIS components and farm machinery scheduling model, the latter realizes the real-time monitoring, scheduling of farm machinery, querying the historical trace of farm machinery and so on. The system provides a doable solution for long-distance and fast information collection and real-time monitoring and effective scheduling of farm machinery.

Equipments in Agricultural products quality and safety traceability systems should maintain accurate time synchronization to ensure the records of agricultural products are valid and reliable. Based on Simple Network Time Protocol (SNTP) and characteristics of traceability system, a low cost, small load and more reliable time synchronous network was designed. The GPS was chosen as clock source and this time synchronization network consist of three layers including central servers, regional time servers and production and sale companies or organizations. The structure of this network can be adjusted flexibly according to the actual situation. The implementation codes of time synchronization server and client were encapsulated as the standalone class library in the form of Dynamic Linking Library, which was combined with available traceability system conveniently. Utilizing this network, the time synchronization precision among equipments in traceability system can reach several tens of millisecond, which meet the requirements of agricultural products quality traceability.

饲料配方软件为合理利用饲料资源、降低饲粮成本发挥了巨大作用.在掌上电脑上设计和开发了通用型饲料配方系统,系统包含配方计算、配方浏览、数据管理、系统维护和系统升级等主要功能模块.开发了嵌入式数据库访问中间件,提高了掌上电脑上数据操作的效率和系统的稳定性:采用两阶段法和直接计算逆矩阵的方式对配方求解的单纯形算法进行了优化,根据参算原料种类的数量,实际计算一次配方时间约为2～4 s;实现了基于存储卡和网络的两种升级方式,保证了系统原料和饲养标准数据的时效性.在北京市4个郊区县31个养殖场户进行了应用,结果表明,系统稳定实用、操作简易,容易被中小养殖户接受,具有较大的推广价值.

Two approaches of integrated programming based on Component Object Model(COM) are introduced. One utilizes the automation server provided by Matlab. The other compiles the Matlab program written in M scripting language to component by using Matlab COM builder, then invoking it in Visual C#. The usual spatial interpolation algorithm in GIS is implemented by these two approaches. The advantages and defects of them are discussed, and the adaptive application range is suggested. The result is that the COM based methods for integration, which make full use of the two platforms, can speed up software development and improve its performance.

Soil electric conductivity (EC) is an integrated indicator for soil physical and chemical properties that are strongly related to crop yield and can be measured quickly, precisely, continuously and cheaply. Study of relationship between crop yield and soil EC can support the application of soil EC in precision farming and reduce the cost of precision farming. Combine CASE 2366 was used to harvest winter wheat and wheat yield map was produced after error sources in yield data were disposed. Veris 3100 EC meter was used to measure soil EC at soil depths of 0 similar to 30.5 cm and 0 similar to 91.5 cm, respectively, and soil EC at 30.5 similar to 91.5 cm was calculated from the soil EC at 0 similar to 30.5 cm and 0 similar to 91.5 cm. The spatial distribution maps of EC of the three different soil depths were produced. The wheat yield map and soil EC maps were interpolated respectively to a grid data with the grid size of 2m x 2m. The relationship between wheat yield and soil EC at the three different soil depths were then analyzed. Statistical analysis showed negative correlation between wheat yield and soil EC at all the three depths. Highest correlation happened between wheat yield and soil EC at 0 similar to 91.5cm, whereas lowest correlation between wheat yield and soil EC at 0 similar to 31.5cm. Regression analysis indicated that the quadratic polynomial model fits the relationship between wheat yield and soil EC very well. There is an optimum soil EC range for wheat growth. Soil EC, a comprehensive index of soil physical and chemical properties, can serve as a proxy for soil productive potentiality at a certain degree, and can be used to analyze spatial variability of crop yield, determine management zones, and calculate variable-rate prescription for precision farming.

Based on Desktop PC, many feed-formula systems have been developed. It is expensive to be widely applied. The regularly users are only some advanced culturists and professional breed technicians. A general purpose PDA-based feed-formula system has been designed and developed. The framework structure and function modules of the system were introduced. The development and operating environment were indicated. An embedded database middleware was designed and implemented in order to promote developing efficiency and decrease its complexity. Two updating ways, storage card updating and network updating, were adopted by this system. To cut down the unnecessary burden of reinstallation and reconFig. of software on users, the automatic installing has been implemented. The system has been compared with those counterparts based on Desktop PC. The result shows that stabile and practical feed-formula system can be developed based on PDA. Characterized by easy to operate, cheap and light to be taken along, this system is very suiTable for the small and medium scale culturists and breed technicians from feed enterprises.