Late Fall Site-Specific Soil Nitrate Upper Limits for Groundwater Protection Purposes

摘要: For temperate regions, such as Germany, a simple management model is developed, with which NO{sub 3} seepage losses during winter can be estimated, when the amount and distribution of soil in late fall are known. The semi-analytical, one-dimensional developed for homogeneous soils. derived steady-state flow conditions at constant water content (field capacity). Essential part solute transport equation based on mixing-cell theory. Sample calculations show that height {Delta}z mixing-cells chosen = 2D/v, where D dispersion coefficient v pore velocity, results compare well from convective-dispersive models. advantage solutions frequently appear mathematical expressions. With sample concerning were carried out variety site conditions. vary considerably, even initial 3}-N same. also if limit set total tolerable winter,more » site-specific upper limits derived. A table values, wide range site-conditions, presented. 25 refs., 4 figs., 6 tabs.« less