Control of mass flow systems for the harmonious balance of intensive utilization and environmental protection of a peatland

本研究的目的是构建一个适当的质量流管理系统，该系统适用于协调用于改良粮食生产的农用地开垦技术和用于维持和保护泥炭地环境和生物资源的技术。以北海道碧柏泥炭地为试验田，对约50hm2的天然沼泽泥炭区和沼泽泥炭区周围农田的质量流态进行了测量和分析，以寻找合适的质量流管理系统。在天然泥炭区，冬季积雪下地表高程最多下降20 cm，并随着积雪的融化而恢复。沼泽的导热系数很小，在沼泽与雪的交界处，雪不容易融化，导致地下水供应短缺。天然沼泽泥炭区Wa…S覆盖较多的植物主要有两种，沼泽本身地下水位较高的地方和地下水位较低的低矮竹林。在两种覆盖植物下，这片沼泽区的透过率几乎相等，定义为从地表向下到给定深度(我们这里选择180厘米)的渗透系数的积分。在过渡泥炭区，发现了渗透系数的显著各向异性和不可逆收缩行为。沼泽地区泥炭与粘性土混合程度不大，渗透系数各向异性不大，土壤进入大气的N_2O气体通量与土壤中气体浓度梯度成正比。据估算，旱地土壤的热通量为8~14 ng/m~2s，临时旱地为2~10 ng/m~2s，沼泽区为0~1 ng/m~2s。碧白泥炭地的热特性主要归因于其热导率对水分的高度依赖性以及与一般土壤相比热导率很小。较少

The purpose of this study was to construct an appropriate mass-flow-managing-system which is suitable to harmonize technologies that is required to reclaim the agricultural lands for the improvements of food productions and technologies that is required to sustain and conserve the environmental and biological resources in peatlands. Bibai peatland, Hokkaido, was selected as a test field, where the mass flow patterns both within the natural bog peat area of about 50 ha and in the cultivated agricultural lands surrounding the bog peat area were measured and analyzed to find the appropriate mass-flow-managing-system.In the natural bog peat area, the elevation of the land surface decreased at most 20cm under the accumulated snow in winter season and restored with the melt of snow. The thermal conductivity of bog was so small that the snow may not melt easily at the interface between the bog and snow, resulting in the shortage of water supply to the groundwater. The natural bog peat area wa … More s covered with mainly two kinds of plants, the bog itself where the ground water level was relatively high and the low bamboo where the ground water level was relatively low. The transmissivities of this bog area, defined by the integration of the hydraulic conductivity from the land surface down to the depth given (we chose 180 cm here), were almost equal under both covering plants. In the transient peat area, we found remarkable anisotropy of hydraulic conductivity and irreversible shrinkage behavior of them. In the fen area, the peat was more or less mixed with clay soils and the anisotropy of hydraulic conductivity was not so large.N_2O gas fluxes from the soils into atmosphere were proportional to the gradient of gas concentrations within the soil. The fluxes were estimated to be 8 to 14 ng/m^2s in the upland fields, 2 to 10 ng/m^2s in the temporary uncultivated rice fields, and 0 to 1 ng/m^2s in the bog area.The thermal feature of Bibai peatland was mainly attributed to the high dependence of their thermal conductivity on water content and to the very small values of them comparing with those of usual soils. Less