Regulatory functions of soil-plant ecosystems to geochemical element cycling

土壤-植物系统在系统中进行元素循环。元素循环通过元素在土壤圈和大气之间的相互扩散以及从土壤圈向水圈的流出来决定水圈和大气的质量。本研究旨在探讨土壤-植物系统中元素的循环过程，并评价人类活动对土壤-植物系统中元素排放的影响。森林生态系统中碱-阳离子循环的调查结果表明，森林土壤中的碱-阳离子减少，而植物中的碱-阳离子增加。这表明大气输入对于维持土壤-植物系统是不可或缺的。然而，大气中铵的供应导致土壤因硝化作用而酸化。一般来说，氮供应促进植物生长，但更大的生长也需要其他营养物质。因此。土壤酸化效应是由于植物对碱性阳离子的吸收加速，土壤酸化会降低植物的生长。因此，从最小值定律的角度来看，大气输入中的植物营养平衡是重要的。同样，过量施肥引起硝酸盐淋溶和氧化亚氮的排放，导致水层和大气质量的退化。城市土地利用变化和废弃物控制也对区域尺度上的元素循环产生影响。例如，为维持水资源而建设的水坝湖成为甲烷排放的来源，这表明更大的影响不仅仅是减少森林土壤的面积，森林土壤从大气中吸收甲烷。北海道区域氮素循环调查表明，集约化农业经营导致耕地土壤富营养化。许多人类和动物的废物没有得到回收利用，废物中的大量氮被排放到河流中。在这个问题上，受最小值规律限制的森林土壤和富营养化耕地不具备调节这种倾斜的区域养分循环的能力。土壤-植物系统通过植物吸收和有机物分解等生物地球化学元素循环调节地球化学元素循环。然而，土壤-植物系统也受大气输入的影响，容易受到人类活动的影响。因此，维持环境质量的土壤-植物系统和系统本身的调节功能可能是脆弱的。我们应该保存函数和系统。因此，有必要研究生物地球化学循环中营养物质之间的相互关系。少

Soil-plant system develops element cycling in the system. Element cycling determines the quality of aquasphere and atmosphere by inter-diffusion of elements between pedosphere and atmosphere and outflow from pedosphere to aquasphere. This study was conducted to investigate the element cycling and to evaluate the effect of human activity on element discharge from the soil-plant system.Results obtained from the investigation for base-cation cycling in forest-ecosystems showed those base cations in forest soils decreased, while base cations in plants increased. This suggests that atmospheric input is indispensable to sustain the soil-plant system. However, atmospheric supply of ammonium induces soil acidification due to nitrification. Generally, nitrogen supply improves plant growth, but bigger growth also requires other nutrients. Therefore. the induced soil acidification effect is due to the acceleration of base cation uptake by plant Consequently, soil acidification will reduce plant g … More rowth. Thus, plant-nutritional balance in atmospheric inputs is important from the viewpoint of the law of the minimum, In the same manner, excess fertilization induces nitrate leaching and emission of nitrous oxide, resulting in the degradation of the quality of aquasphere and atmosphere.Land use change and waste control in urban area also influenced element cycling in regional scale. For example, dam-lake constructed to maintain water resources became a source of methane emission, indicating that a greater impact occurs more than just decreasing the area of forest soil, which absorbs methane from the atmosphere. Investigation of regional nitrogen cycling in Hokkaido indicated that amble land soil became eutrophic due to intensive agricultural management. Many human and animal wastes were not recycled and a substantial amount of nitrogen from the wastes was discharged to the river. Concerning this problem, a forest soil limited by the law of the minimum and an eutrophic arable land do not have any capacities to regulate such kind of skewed regional nutrient cycling.Soil-plant system regulates geochemical element cycling by means of biogeochemical element cycling including plant uptake and organic matter decomposition. However, soil-plant system is also influenced by atmospheric inputs and is easily changed by human activity. Consequently, the regulatory function of soil-plant system and the system itself may be fragile to maintain environmental quality. We should conserve the function and the system. Therefore, it is required to study the interrelationship between nutrients in biogeochemical cycling. Less