Abstract
In order to simulate the behavior of NO3 in the agricultural land, it is necessary to obtain the information of the relationship between solute concentrations of pore water and adsorbed solute amount, which are described as the adsorption isotherm (AI) lines at six depths. However, the parameters list of the AIs, which depend on soil type, has not yet been provided with all as inventory data. There-fore, it is necessary to provide with all parameter list as in-ventory data immediately. For the purpose of collection in substantial inventory data of AIs of NH+4 and NO−3, as the first step, the authors conducted the adsorption experiment of Andosol and Gray lowland soil at the arbitrary depth. As a result, the AI lines in all soil type except for Andosol (30 cm depth of upland field) could be expressed as Langmuir type AI. In the Andosol (upland field), maximum adsorp-tion NH+4 tended to decrease with depth except for z = 50 cm, while adsorbed NO−3 was strongly dependent on depth and its maximum adsorption tended to increase with depth.
