We noted that ammonia nitrogen was not adsorbed by the cultivated layers of highly permeable paddy fields during the initial fertilization period, but reached the lower layers relatively early. In our study, we considered an exponential equation from an aqua-environmental perspective with the goal of obtaining good growth of rice plants in order to estimate the concentrations and integrated volume of ammonia nitrogen accompanying paddy percolation. Using this exponential equation, we were able to derive a relation between time and concentrations of paddy percolation water, and hypothesized that if percolation rates were less than 10mm/day, percolation would have no effect on rice growth, while simultaneously helping to maintain the good water quality of the extra-paddy environment. We also clarified the differences between the potential ammonia nitrogen adsorption volume derived from the CEC value and the integrated amount of ammonia nitrogen water in soil, and considered the causes from the perspectives of solute movement and water movement.