FEASIBILITY OF PRECISION FARMING FOR GRASSLAND AGRICULTURE

本研究探讨了草地精准农业的可行性。（草地田间信息系统）在附属农场的草地中提供了四个地方的0.5公顷的试验田。供试草地在第1次和第2次刈割之间的产量图具有相似的趋势。土壤硝态氮浓度在地表至5cm深度处较高（平均210 mg/l），pH值与地表相当低。在这两个方面，与草产量的相关性很低。以半方差分析为基础，对数据采集间隔进行了检验，以估计合适的产量制图系统。利用124个料堆的产量，估计了试验草地产量的最佳数据采集间隔不超过10 m。（草地管理用导航系统的研制）利用DGPS接收机导航系统的工作运行精度为0.4m。利用GPS的三维位置信息进行测量后，可以制作出与常规测量相当的等高线图。利用导航系统的导航功能，进行了施肥制图，并与第1茬草的产量制图进行了比较，结果表明，施肥点对牧草产量的影响不大。基于传感器融合的拖拉机自主行驶系统的研制开发了一种由DGPS接收机、雷达测速仪和陀螺仪组成的拖拉机自主行驶系统。经过草原运行检验，直线运行部分可以在0.3m的偏差范围内运行（采样周期0.5s，速度0.3m/s）。农场上的一系列提议促使工作人员的意识发生变化，通过可视化拖拉机的运行轨迹和草产量来提高工作精度。此外，通过一个试验性的生产系统，可以预期以精确农业为目标的新型农场管理的可行性。

This study investigated feasibility of the Precision Farming for grassland.(Field information system for grassland)Test field of 0.5 ha in amount in four places was provided into the grass field at the attachment farm. The yield map of the tested grassland between 1st and 2nd grass cutting had the similar tendency. The nitrate nitrogen concentration at the ground surface to 5 cm depth was high (210 mg/ 1in average), but pH was as low as the surface. In both, correlation with grass yield was low. Data acquisition interval was examined to estimate the appropriate yield mapping system based on Semi-variance analysis. Optimum data acquisition interval on yields of the tested grassland was estimated less than 10 m using the yield of 124 windrows.(Development of navigation system for the grassland management)The work running precision when using navigation system by the DGPS receiver was 0.4 m. After measuring using the position information of the 3 dimension of GPS, the contour map that is equal to conventional survey could be made. Using the function of navigation system, manure-spraying mapping was made, After comparing manure spraying mapping and yield mapping in the 1st grass, an influence of spraying speckles on grass yield was hardly seen.(Development of tractor autonomous running system by the sensor fusion)Tractor autonomous running system, which combined DGPS receiver, a radar speedometer and a gyro, was developed. After examining in the running by the grassland, the straight line running part could be run within the 0.3 m deviation (sampling period 0.5s, speed 0.3m/s).A series of overtures on the farm prompted for the improvement of the work precision by the visualization of a tractor's running trace and grass yield as the consciousness of the work member changed. Moreover, by using an experimental production system, feasibility of new farm management, which aimed at the Precision Farming, could be expected.