Fundamental Studies on the Spatial Variation of Energy and Material Cycling in Agricultural Ecosystems.

通过详细的土壤调查，明确了微地形条件对土壤性质空间变异的影响，特别是土壤植物系统的能量和水分平衡。为了更好地掌握空间格局，介绍了几种图像处理方法，包括热图像处理方法，并通过田间详细的土壤测试进行了验证。研究结果可概括为以下几个方面。在详细的地形分析之后，在北海道的丘陵地区选择了几个调查区，并在野外以20x20m网格固定的地点进行了系统抽样。编制了大比例尺土壤属性图，特别是137Cs图，并与地形分析结果进行了比较。丘陵地区放射性沉降物(~(137)Cs)的空间分布与土壤固体物质的剥蚀-沉积过程密切相关，而剥蚀-沉积过程主要受坡面形态和场地位置控制。为更好地掌握土壤条件的空间分布，研究了自动定量解译的方法。测量反射红光强度的传感器对于测量普通航空照片的密度是有用的。一台热像仪(INFRA-EYE5000)可有效地获取土壤和植被表面的能量平衡。由于土壤表面温度受地表蒸发冷却的控制，因此可以通过物理模型来评估地表的能量和水流及其空间变化。在此基础上，制定了田间测定的常规程序和研究土壤能量和水分平衡空间变异的分析方法。

Detailed soil surveys were conducted to make clear the influence of micro-topographical condition on the spatial variation of soil properties, especially energy and water balance of soil plant system. To get a good grasp of spatial patterns several methods for image processing, including a thermal image processyr, were introduced and checked by detailed soil examinations in the field. The results can be summarized as follows.1. After the detailed terrain analysis several survey areas were selected in the hilly areas of Hokkaido and systematically sampled at sites fixed by a 20x20m grid in the field. Large scale maps of soil properties, especially of 137Cs, were prepared and compared with the results of terrain analysis. The spatial distribution of radioactive fallouts(137Cs) in the hilly areas was closely dependent upon the denudation-sedimentation processes of the solid soil materials that was controlled mainly by slope morphology and position at which sites were located.2. Methods for automatic quantitative photo-interpretation were studied to make a good grasp of the spatial distribution of soil condition. A sensor which measures the intensity of reflected red light were useful to measure the density of ordinary aerial photographs.3. A thermal image processor(INFRA-EYE5000) was effective for the purpose to grasp the energy balance of the soils and vegetated surfaces. Because of the soil surface temperature was controlled by the cooling due to evapolation from the surface under consideration, the energy and water flow across the surface and their spatial variation could be evaluated by using the physical models. Based on the results described above, routine procedures for the measurement by using the apparatus in the field and analytical methods for studies on the spatial variation of energy and water balance of soils were worked out.